[House Hearing, 114 Congress]
[From the U.S. Government Publishing Office]
UNLOCKING THE SECRETS OF THE UNIVERSE:
GRAVITATIONAL WAVES
=======================================================================
HEARING
BEFORE THE
COMMITTEE ON SCIENCE, SPACE, AND TECHNOLOGY
HOUSE OF REPRESENTATIVES
ONE HUNDRED FOURTEENTH CONGRESS
FIRST SESSION
__________
February 24, 2016
__________
Serial No. 114-61
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Printed for the use of the Committee on Science, Space, and Technology
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COMMITTEE ON SCIENCE, SPACE, AND TECHNOLOGY
HON. LAMAR S. SMITH, Texas, Chair
FRANK D. LUCAS, Oklahoma EDDIE BERNICE JOHNSON, Texas
F. JAMES SENSENBRENNER, JR., ZOE LOFGREN, California
Wisconsin DANIEL LIPINSKI, Illinois
DANA ROHRABACHER, California DONNA F. EDWARDS, Maryland
RANDY NEUGEBAUER, Texas SUZANNE BONAMICI, Oregon
MICHAEL T. McCAUL, Texas ERIC SWALWELL, California
MO BROOKS, Alabama ALAN GRAYSON, Florida
RANDY HULTGREN, Illinois AMI BERA, California
BILL POSEY, Florida ELIZABETH H. ESTY, Connecticut
THOMAS MASSIE, Kentucky MARC A. VEASEY, Texas
JIM BRIDENSTINE, Oklahoma KATHERINE M. CLARK, Massachusetts
RANDY K. WEBER, Texas DONALD S. BEYER, JR., Virginia
BILL JOHNSON, Ohio ED PERLMUTTER, Colorado
JOHN R. MOOLENAAR, Michigan PAUL TONKO, New York
STEPHEN KNIGHT, California MARK TAKANO, California
BRIAN BABIN, Texas BILL FOSTER, Illinois
BRUCE WESTERMAN, Arkansas
BARBARA COMSTOCK, Virginia
GARY PALMER, Alabama
BARRY LOUDERMILK, Georgia
RALPH LEE ABRAHAM, Louisiana
DARIN LAHOOD, Illinois
C O N T E N T S
February 24, 2016
Page
Witness List..................................................... 2
Hearing Charter.................................................. 3
Opening Statements
Statement by Representative Lamar S. Smith, Chairman, Committee
on Science, Space, and Technology, U.S. House of
Representatives................................................ 7
Written Statement............................................ 9
Statement by Representative Eddie Bernice Johnson, Ranking
Member, Committee on Science, Space, and Technology, U.S. House
of Representatives............................................. 11
Written Statement............................................ 13
Statement by Representative Bill Foster, Committee on Science,
Space, and Technology, U.S. House of Representatives........... 15
Written Statement............................................ 13
Witnesses:
Dr. Fleming Crim, Assistant Director, Directorate of Mathematical
and Physical Sciences, National Science Foundation
Oral Statement............................................... 18
Written Statement............................................ 20
Dr. David Reitze, Executive Director of LIGO, California
Institute of Technology
Oral Statement............................................... 27
Written Statement............................................ 29
Dr. Gabriela Gonzalez, Professor of Physics and Astronomy,
Louisiana State University
Oral Statement............................................... 36
Written Statement............................................ 38
Dr. David Shoemaker, Director, LIGO Laboratory, Massachusetts
Institute of Technology
Oral Statement............................................... 45
Written Statement............................................ 48
Discussion....................................................... 54
Appendix I: Answers to Post-Hearing Questions
Dr. Fleming Crim, Assistant Director, Directorate of Mathematical
and Physical Sciences, National Science Foundation............. 82
Dr. David Reitze, Executive Director of LIGO, California
Institute of Technology........................................ 83
Dr. Gonzalez, Professor of Physics and Astronomy, Louisiana State
University..................................................... 85
Dr. David Shoemaker, Director, LIGO Laboratory, Massachusetts
Institute of Technology........................................ 87
UNLOCKING THE SECRETS OF THE UNIVERSE:
GRAVITATIONAL WAVES
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WEDNESDAY, FEBRUARY 24, 2016
House of Representatives,
Committee on Science, Space, and Technology,
Washington, D.C.
The Committee met, pursuant to call, at 10:07 a.m., in Room
2318 of the Rayburn House Office Building, Hon. Lamar Smith
[Chairman of the Committee] presiding.
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Chairman Smith. The Committee on Science, Space, and
Technology will come to order,
Without objection, the Chair is authorized to declare
recesses of the Committee at any time.
Welcome to today's hearing titled ``Unlocking the Secrets
of the Universe: Gravitational Waves.'' I'll recognize myself
for five minutes for an opening statement and then the Ranking
Member.
Last September, American scientists in Louisiana and
Washington State detected a signal from an event so powerful
that it sent a detectable ripple 1.3 billion light years ago
through time and space to Earth. Albert Einstein was right:
gravitational waves do exist. A century ago, Einstein developed
his theory of general relativity. He then predicted that
intense energy events, like the collision of black holes, could
cause such disruption to the universe that they would emit
waves that distort time and space much like the ripples on a
pond caused by a thrown rock.
After decades of effort, scientists have now observed
Einstein's theory in practice. They witnessed the effect of two
black holes colliding, which released 50 times the energy of
all the stars in the universe put together that emitted a
gravitational wave across the universe that was, for the first
time, detected on Earth. The discovery was the work of hundreds
of scientists, decades of ingenuity and innovation, and the
commitment of the United States through the National Science
Foundation.
Forty years ago, a group of scientists began to design an
experimental system to detect gravitational waves on Earth.
Then they submitted a proposal for funding to the National
Science Foundation. In 1990, the National Science Board
approved funding for the project. Since that time, NSF has
supported development of the Laser Interferometer
Gravitational-Wave Observatory, or LIGO. This included
construction and upgrades, operations, and research awards to
scientists who study LIGO data. Today we will learn more about
the value to America of that investment. We will also hear
about the monumental success that has resulted from advances in
physics, astronomy, engineering, and computer science. The
NSF'' support for the LIGO project is a great example of what
we can achieve when we pursue breakthrough science that is in
the national interest.
We have the privilege today of hearing from a panel of
witnesses who helped make the discovery. They are leaders of
the 1,000 scientists and 80 scientific institutions that make
up the global LIGO Scientific Collaboration. We look forward to
hearing more about the discovery, what it means for American
science and innovation, and what new research and applications
may be generated by this breakthrough. With this discovery, we
embark on a new and exciting time for American physics and
astronomy, and we move closer to a better understanding of the
universe.
This is a quote by Dr. Kip Thorne, a renowned American
physicist and one of the founders of LIGO: ``With this
discovery, we humans are embarking on a marvelous new quest:
the quest to explore the warped side of the universe, objects
and phenomena that are made from warped space-time. Colliding
black holes and gravitational waves are our first beautiful
examples.''
Congratulations to the scientists on their great discovery.
[The prepared statement of Chairman Smith follows:]
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Chairman Smith. That concludes my opening statement, and
the gentlewoman from Texas, Eddie Bernice Johnson, is
recognized for hers.
Ms. Johnson. Thank you very much, Mr. Chairman. I'm
delighted that you're having this hearing today. It is
gratifying to be hearing about a very exciting scientific
breakthrough.
I want to congratulate each of the panelists, and welcome
you, for your role in anything that you participated when it
comes to LIGO. Thank you for being here this morning to talk
about what this achievement means for science, and for our
Nation, and about the long-term commitment to high-risk, basic
research that made it all possible.
The story of the Laser Interferometer Gravitational-Wave
Observatory is a story about the talent, creativity, and
perseverance of U.S. scientists and engineers. It is a story
about the 65-year commitment of the National Science Foundation
to high-risk, basic research. I truly believe that a Nobel
Prize will be coming. And it is a story about what we stand to
lose as a Nation if we fail to maintain faith in our
scientists, and in the scientific process exemplified by the
National Science Foundation that is the envy of nations around
the world.
When LIGO was first proposed by a small group of physicists
from MIT and Cal Tech, many scientists responded, ``You're
crazy. It is not possible to build a gravitational-wave
detector.'' Many of the scientists at the National Science
Foundation and the National Science Board also quietly wondered
if it was possible. But the project leaders presented a
compelling plan, and the Foundation, then under the
Administration of George H.W. Bush, decided to take the gamble.
Because that is what the National Science Foundation does. It
supports high-risk, but potentially high-reward, basic science
that nobody else will do.
Today, we celebrate the scientific and technological
achievement that LIGO represents. However, the path to this
point was not smooth. When the National Science Foundation
first proposed to build LIGO, debates raged in the scientific
community and in Congress. Many scientists were concerned about
protecting funding for competing physics and astronomy projects
that were also important. They were also concerned about
squeezing resources for research grants. Those concerns were
understandable, and eventually led to the creation of a
separate facilities construction account at the Foundation.
Members of Congress, including Members of this Committee,
were also skeptical. This was a very expensive project, and
some scientists doubted that it was technologically feasible.
Members also wondered, what exactly are gravitational waves and
why should we care? Throughout these debates and despite the
elimination of funding by Congress in the first year that LIGO
was proposed and the attempt to do so again in the second year,
the National Science Foundation kept faith in the scientists
and in its own mission.
Notwithstanding some of the debates we have had here in
recent weeks, the primary purpose of the National Science
Foundation is not to strengthen national security, or improve
public health, or even to grow our economy. To be sure, those
are all critically important outcomes of National Science
Foundation investments in basic research across all fields of
science and engineering, and some NSF-funded research has
intended applications even at the proposal stage. However, the
essential, core purpose of the National Science Foundation is
to promote the progress of science, whether or not there is a
foreseeable or intended application, and to train the next
generation of U.S. scientists and engineers. And it is clear
that the Foundation's bold investments in LIGO, driven by that
core purpose, have led to a major scientific breakthrough.
Today's hearing serves as a reminder not just of how
talented U.S. scientists and engineers are, but of why we must
work hard to maintain our status as the best country in the
world to do science by continuing to fund NSF and encourage
high-risk taking. This is a lesson that we should apply to the
entire agency, and not just to certain fields of our choosing.
Twenty-five years ago, many Members of Congress did not
want to fund the search for gravitational waves. After all, how
was that in the national interest? But enough Members did dare
to imagine, and here we are today.
Again, I want to thank you and congratulate the witnesses,
and now I will yield the remainder of my time.
[The prepared statement of Ms. Johnson follows:]
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Chairman Smith. Thank you, Mrs. Johnson. I might point out
that 25 years ago in 1994, we had a Republican-controlled
Congress who took the lead in funding LIGO, and I know it was a
bipartisan effort, but it's nice to see that reach over the
span of 25 years.
Ms. Johnson. Could I yield to Mr. Foster?
Chairman Smith. Sure. We will recognize the gentleman from
Illinois, Mr. Foster, for one minute.
Mr. Foster. Thank you, Mr. Chairman, and thank you to the
witnesses for coming here today to talk about this very
exciting discovery. As the only Ph.D. scientist in Congress,
I'm probably more excited about this than most others who've
come to hear this today.
A century after Einstein theorized the existence of
gravitational waves, 50 years after Rai Weiss began thinking of
an interferometric gravitational-wave detector as part of a
class exercise at MIT, 40 years after the spin-down of orbiting
neutron stars starting giving the first hints that
gravitational waves were being emitted from astrophysical
sources, and 25 years after the National Science Foundation
began courageous and sustained funding for an international
collaboration of hundreds of scientists to begin constructing
this large and technically risky project, physicists have
spectacularly confirmed Einstein's theory. This is a discovery
that will live on in the science textbooks forever.
And with this discovery, we have opened a new window onto
the universe and we have verified that our new telescope is
working and now the fun begins.
Thank you, and I yield back.
[The prepared statement of Mr. Foster follows:]
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Chairman Smith. Thank you, Mr. Foster.
I keep telling Dr. Foster that my going off to college
thinking I was going to be a physics major counts almost as
much as his Ph.D. but not quite.
Our first witness today is Dr. Fleming Crim, Assistant
Director, Directorate of Mathematical and Physical Sciences at
the National Science Foundation. Dr. Crim joined NSF in 2013.
Prior to his time at NSF, he was the John E. Willard and
Hilldale Professor in the Department of Chemistry at the
University of Wisconsin-Madison, where his research group used
lasers to understand chemical reaction dynamics that occur in
gases and liquids. Dr. Crim has lectured around the world and
published more than 150 papers. He received his bachelor's
degree from Southwestern University and his Ph.D. from Cornell
University.
Our second witness today is Dr. David Reitze, Executive
Director of the Laser Interferometer Gravitational-Wave
Observatory at the California Institute of Technology. Dr.
Reitze's extensive work in the area of experimental
gravitation-wave detection dates back to the mid-1990s. He has
authored or co-authored over 250 peer-reviewed publications.
Dr. Reitze is currently a Fellow of the American Physical
Society and the Optical Society, and has served on numerous
scientific advisory and program committees within the physics
and optics communities. Dr. Reitze received his Ph.D. in
physics from the University of Texas at Austin.
Our third witness today is Dr. Gabriela Gonzalez, Professor
of Physics and Astronomy at Louisiana State University, where
her research involves the detection of gravitational waves with
interferomic detectors. Dr. Gonzalez was a founding member of
the LIGO scientific collaboration and has participated in the
commissioning of the LIGO detector at the Livingston
Observatory. Dr. Gonzalez received her master's degree from the
University of Cordoba in Argentina and her Ph.D. from Syracuse
University.
Our final witness is Dr. David Shoemaker, Director of the
LIGO Laboratory at the Massachusetts Institute of Technology,
where his research focuses on instrumentation to enable the
observation of gravitational radiation by precision measurement
techniques. Dr. Shoemaker's work in the field of gravitational-
wave detection began in 1980. He spent several years at Max
Planck in Garching, Germany, and the CNRS in Paris, France,
where he helped to develop specific technologies for
gravitational-wave detection. Dr. Shoemaker has served on
numerous scientific advisory and program committees for the
NSF, NASA, and for the European Gravitational Wave Observatory.
He received his master's degree in physics from MIT and his
Ph.D. in physics from the University of Paris.
We welcome you all. We really appreciate your efforts in
being here. You all are the experts. You led the way in one of
the greatest scientific discoveries that we will ever hear
about. What really caught my attention was the energy release
being far beyond the energy of all the stars of the universe.
That tends to rivet one's not only attention but imagination,
so we appreciate you all being here, appreciate your expert,
and Dr. Crim, we'll begin with you.
TESTIMONY OF DR. FLEMING CRIM,
ASSISTANT DIRECTOR,
DIRECTORATE OF MATHEMATICAL
AND PHYSICAL SCIENCES,
NATIONAL SCIENCE FOUNDATION
Dr. Crim. Thank you, Mr. Chairman.
Before I begin my remarks, I would like to show a short
video clip, just over one minute, on LIGO and its detection of
gravitational waves.
[Video shown]
Chairman Smith. Thank you. We won't count that against your
five minutes.
Dr. Crim. Thank you very much. Mr. Chairman, Ranking Member
Johnson and members of the Committee, I appreciate your
interest in the historic observation of gravitational waves by
the Interferometer Gravitational Wave Observatory.
My colleagues will describe the exciting science but I will
spend a few minutes describing the role of the National Science
Foundation and the rewards of fundamental research.
Although Albert Einstein predicted gravitational waves in
1916, their direct observation was a daunting, seemingly
impossible task. Nonetheless, the possibility of opening a new
window on the universe was so tantalizing that NSF began
funding research on prototype laser interferometers in the
1970s.
In the 1980s, the NSF committed almost $300 million to a
group led by Kip Thorne and Ron Drever of Cal Tech and Rainer
Weiss of MIT to transform these prototypes into a full-blown
gravitational-wave observatory. This effort driven by
brilliance, vision, enthusiasm, experimental prowess and deep
theoretical insights persuaded the NSF, the National Science
Board, and Congress to take a risk.
Even though NSF had never funded anything on such a scale,
the potential for transformative science was worth it. LIGO was
the first of our Major Research Equipment projects, now known
as MREFC projects. It illustrated the importance of distinct
funding for instruments of this scale and prompted fruitful
discussions with Congress. NSF embraced a new role in funding
large, high-risk, high-reward research platforms serving the
Nation by betting boldly on the future.
The National Science Board approved construction of LIGO in
1990, and following Congressional approval, work began in 1994.
LIGO started operations in 2002, allowing researchers to gather
data and develop innovative technologies.
One of the primary motivators for this arduous research was
the question of whether it was possible to build an instrument
of the requisite sensitivity. Indeed, the answer turned out to
be yes. Thus, in 2008, NSF and Congress understood the
compelling case and approved the $200 million of funding for
constructing the next generation Advanced LIGO, the instrument
that detected a gravitational wave last fall.
That gravitational wave arose in the collision and merger
of two black holes approximately 1.3 billion years ago. The
wave propagated to the detectors in Livingston, Louisiana, and
Hanford, Washington, and produced a chirp that opened a new
window on the universe.
This discovery is a beginning, not an end. It marks the
birth of gravitational-wave astronomy, a new tool for
understanding the cosmos.
The really good news is that Advanced LIGO was designed to
be three times still more sensitive and should begin
observations with even greater reach this summer.
The United States has led this international collaboration.
However, continued close cooperation with our international
partners is key to taking the science to the next level. New
observational capabilities that our partners in Europe, Japan
and India are either building or planning promise an exciting
future.
LIGO is a national and international collaboration in which
cooperation drives the science and leverages precious
resources. The LIGO scientific collaboration is a group of more
than 1,000 scientists at universities around the United States
and in 16 countries. I'm pleased to add, Mr. Chairman and
Ranking Member Johnson, that 30 members of that collaboration
come from Texas.
Mr. Chairman, this historic measurement illustrates the
importance of NSF and exemplifies its role in advancing
discovery. The majesty of exploring our universe motivates this
ambitious experiment, but as with all fundamental science, LIGO
offers other important benefits. The science will advance
education, inspiring students in developing the workforce our
society requires. It has and will continue to spawn
collaborations in engineering, computer science, and other
fields to make the Nation more competitive. The fruits of NSF-
sponsored research drive our economy, enhance our security, and
ensure our global leadership.
Basic research is uncertain and risky but it is also
revolutionary. LIGO is a striking example but not the only one.
Fundamental science has transformed our world and will continue
to change it in ways we have not yet imagined. All the
contributors to LIGO--scientists, the National Science
Foundation, the National Science Board, and Members of
Congress--deserve to take enormous prid in our collective
accomplishments.
These comments conclude my testimony. I'll be pleased to
answer questions.
[The prepared statement of Dr. Crim follows:]
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Chairman Smith. Thank you, Dr. Crim.
And Dr. Reitze.
TESTIMONY OF DR. DAVID REITZE,
EXECUTIVE DIRECTOR OF LIGO,
CALIFORNIA INSTITUTE OF TECHNOLOGY
Dr. Reitze. Chairman Smith, Ranking Member Johnson, Members
of the Committee, thank you for holding this very important
hearing. I'm delighted and honored to be testifying before you
today. My name is Dr. David Reitze. I'm the Executive Director
of LIGO. I'm based at the California Institute of Technology.
On February 11th, my colleagues and I announced to the
world the first detection of gravitational waves from two
colliding black holes. This is truly a stunning discovery. It
comes 100 years after Einstein first published his general
theory which predicted gravitational waves, and it was made
possible only after a 40-year dedicated effort of experiment
and theory funded by the National Science Foundation with your
support, with Congressional support.
This discovery is in and of itself an incredible scientific
and engineering feet and it proves that Einstein was right once
again. However, the detection is really much, much more than
that. Up until this point, humanity had never observed two
colliding black holes merging to form one. This is a stunning
discovery. It's what my colleague Kip Thorne calls ``a storm in
space-time.'' For the first time, we're probing the universe in
a completely new way. Indeed, before this discovery, we hadn't
even known that black holes existed in pairs.
LIGO is a new kind of astronomical receiver similar to a
radio telescope and can directly hear vibrations in space-time.
The gravitational window opened by LIGO dramatically differs
from all other windows. LIGO should be able to detect things
that no other type of astronomical telescope will detect.
Einstein tells us that space-time is warped, that gravity
is geometric, and that black holes exist. It also predicts the
existence of gravitational wave. As you pointed out, Chairman
Smith, they are ripples in the fabric of space-time.
The effect of gravitational waves is mind-bogglingly tiny
so it takes massive objects, 30 stellar-mass black holes
colliding with each to produce detectable waves, and the
changes that we measure to detect them are one one-billionth of
one one-billionth of a meter, incredibly tiny. That's a tiny
fraction of a proton's diameter.
First slide, please, Jose.
[Slide]
To detect gravitational waves, LIGO uses two
interferometers. You see the one from Livingston, Louisiana,
here, each having 4-kilometer arms, and the signal that we
record is actually in the audio band. In other words, we can
hear the signal when we play it through a speaker, and Jose,
could you play the first? That is the sound of two black holes
colliding. Play the next slide, please.
[Slide]
This makes it a little bit easier to hear. We just
frequency-shifted it. Thank you.
Like many scientific discoveries, LIGO had very humble
beginnings. Experiments were carried out in the 1960s and 1970s
by Rainer Weiss of MIT and groups at the University of Glasgow
in Scotland and by Ron Drever in the Max Planck Institute in
Germany along with theoretical efforts in gravitational-wave
physics by Kip Thorne of Cal Tech as well as others.
When LIGO was first proposed as a large-scale project in
the mid-1980s, some deemed the project too risky and too
expensive. NSF, however, recognized both the huge scientific
potential and the cutting-edge technology that could result
from designing and building LIGO.
I believe this discovery is truly a scientific triumph but
I want to set aside that for a moment and focus on some broader
impacts.
LIGO in the United States leads the world in this new form
of astronomy. Large-scale interferometers are currently under
construction in Italy and Japan, and India just last week
announced that it will partner with the LIGO Laboratory to
construct a third identical LIGO interferometer in India. The
world is following the United States into this new scientific
frontier.
In addition, to make LIGO work, we had to develop the
world's most stable lasers, the world's best mirrors and
optics, some of the world's largest vacuum systems as well as
push the frontiers of quantum-measurement science and high-
performance computing. We use a lot of technology, and all the
technology we use, we advance.
In addition, LIGO is a big data generator. We produce
almost one petabyte--that's one million gigabytes--of data per
year. LIGO scientists develop and employ sophisticated computer
algorithms to sift through the data searching for these
gravitational waves, and we use numerical modeling to model the
signals that we expect to see, and that requires high-
performance computers, supercomputers, supplied by NSF XSEDE
and Blue Waters program.
All of this said, I believe that the largest impact from
LIGO in the past and in the future will continue to be the
scientific workforce, the education of scientists and engineers
that we've done over the past 40 years and that we'll do going
forward. Many scientists when they come to LIGO, they fall in
love with it and they choose to stay. However, others go on to
distinguished careers in both high-tech industry and
international laboratories. And in addition, LIGO invites about
20,000 students every year to come and visit our observatory
education and outreach program.
I'll close with the following statement. LIGO is a
testament to the vision and tenacity of scientists like Rainer
Weiss, Kip Thorne, Ron Drever, and others who began these
research programs, but it's also a testament to the National
Science Foundation, whose bold vision and steadfast support and
stewardship enabled this discovery. It's with great
appreciation that I also thank the U.S. Congress for
recognizing the importance of this research and supporting it.
Thank you.
[The prepared statement of Dr. Reitze follows:]
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Chairman Smith. Thank you, Dr. Reitze.
And Dr. Gonzalez.
TESTIMONY OF DR. GABRIELA GONZALEZ,
PROFESSOR OF PHYSICS AND ASTRONOMY,
LOUISIANA STATE UNIVERSITY
Dr. Gonzalez. Chairman Smith, Mr. Beyer and Members of this
Committee----
Chairman Smith. Is your mic totally on, or close enough?
There we go. Thank you.
Dr. Gonzalez. It is an honor to testify here on behalf of
my collaborators. We thank you for your interest and support of
gravitational-wave science.
I'm Dr. Gabriela Gonzalez, a Professor of Physics and
Astronomy at Louisiana State University and the current elected
Spokesperson of the LIGO Scientific Collaboration, or LSC.
Ours is an international collaboration that succeeded
recently in detecting gravitational waves from black holes and
will keep opening a new window to the universe. Can I have the
first slide, please?
[Slide]
As shown in the slide, the LSC, which includes the LIGO
Laboratory, has more than a thousand members in 15 countries
with more than half of those in the United States. The
collaboration was formed almost 20 years ago and is the entity
that carries out the LIGO scientific research program. The LIGO
Laboratory and the U.S. scientists have played a key, very
important role in the LSC scientific and leadership activities.
Also, LIGO has fostered the very effective relationship with
other collaborations with the European Virgo Collaboration and
with the Japanese KAGRA collaboration. The LIGO India project
just approved by the Indian government is part of the LSC
effort. We really lead the world.
[Slide]
As shown in the next slide--can I have the next slide,
please--the LSC has a great diversity of colleges and
universities in 22 different U.S. states. They are top-tiered
private universities, large state universities, undergraduate
and liberal art colleges, as well as institutions with many
underrepresented groups in science. The collaboration effort is
very broad, includes research in many different areas, and this
investigation, all these activities, are geographically very
distributed but the benefits of our research like the recent
detection are common to all. That is one of the strengths of
collaborative work.
We do not receive funding as a collaboration. Each LSC
group seeks funding from agencies for their research based on
their own individual merits. In the United States, the NSF
funds the LIGO Laboratory with cooperative agreement but also
funds the basic research in the many other U.S. groups through
the very competitive research award system, and that guarantees
the quality of the funded activities. Can I have the next
slide, please?
[Slide]
In this chart, and in these pictures, you can see that more
half the LSC members are graduate students, postdoctoral
scholars or undergraduate students. These are young, busy and
happy investigators in training in a very interdisciplinary and
international scientific environment. Undergraduates contribute
to the LSC research program not only in the LSC groups but also
in research experience for undergraduate programs in the United
States funded by the National Science Foundation.
The training in LIGO of all these young scientists is done
at the forefront of science and technology. It's
multidisciplinary. It involves precision measurement
technology, Big Data analysis, a constant need for diagnosis
and problem-solving, as well as basic physics and astrophysics.
There are many career options available to LSC trainees in
academia, national laboratories, and high school science
education as well as cutting-edge industry.
We compiled an incomplete list of companies employing LSC
graduates and they are now working in the human genomics
industry, the U.S. healthcare industry, biomedical information,
oil industry, Microsoft, Google, Boeing, SpaceX, Northrop
Grumman, Synaptics, Celestron, Luminit, Cytec Engineered
Materials, GE Global Research, Geneva Trading, Seagate. We are
training the workforce in the United States.
Many members of the collaboration dedicate a significant
fraction of their time to K-12 education and outreach. The
public's curiosity about our discovery has been intense. Only
last Saturday, almost 1,300 people, some driving for hours to
get there, visited the LIGO Science Education Center at the
LIGO Livingston Observatory in Louisiana. The Science Education
Center is also funded by NSF. And they went there to see where
the science is done and meet some of the scientists who do it.
The national as well as the local coverage of our detection
showed the broad spectrum of scientists working on this field
everywhere. There are many local heroes to celebrate.
In conclusion, the LSC will continue working hard on its
mission to understand the universe better through the newly
opened gravitational-wave window. We are very proud about the
result of our work not just being amazing astrophysical results
but also pushing the technology and contributing to the
progress of society.
We thank NSF and the U.S. Congress for the support of our
activities.
[The prepared statement of Dr. Gonzalez follows:]
[GRAPHICS NOT AVAILABLE IN TIFF FORMAT]
Chairman Smith. Thank you, Dr. Gonzalez.
Dr. Shoemaker.
TESTIMONY OF DR. DAVID SHOEMAKER,
DIRECTOR, LIGO LABORATORY,
MASSACHUSETTS INSTITUTE OF TECHNOLOGY
Dr. Shoemaker. Chairman Smith, Ranking Member Johnson, and
Members of the Committee, thank you for holding this hearing
and inviting me to participate today. I too would like to thank
the Committee for its interest in gravitational waves and LIGO,
and I hope our testimony helps the Committee in its work.
I'm Dr. David Shoemaker. I'm with MIT in Cambridge,
Massachusetts. My role was to have the pleasure and honor to
lead the Advanced LIGO Project. Let's take a look at the first
slide, please.
[Slide]
This was a major project, MREFC, and it came in on time and
on budget. Could we look at the next slide, please?
[Slide]
To round out our testimony, I want to paint a broad picture
of our field and its future. Let's look at the next slide,
please.
[Slide]
What you see here are various images of people at work in
the process of putting Advanced LIGO together.
So our first goal is accomplished, as you heard. We made a
detection, a remarkable thing, but it's just the start of the
new astronomy.
There are more kinds of sources that LIGO can expect to
see. Let's look at the next slide. That's great. Thank you.
[Slide]
One of the ones that I want to talk about are neutron
stars. These are stars which have collapsed from their original
size, not all the way back down to a black hole but to material
so dense that a single teaspoon would weigh 10 million tons, if
you imagine such a thing. They tend to be magnetized and
spinning, and they've got some strange things going on in their
interior that we don't understand. They also can form binaries
like the black holes that we saw, and if we can observe them
both with our gravitational-wave detector as well as with
satellites in space that NASA puts up to look at X-rays and
regular telescopes on the ground that the NSF supplies for our
observatory, we can put together all this information into a
complete package and know more than we could have ever known
without gravitational waves or without this combination, this
synergy of information. So it's a wonderful new way to reuse
tools that have been used for astronomy in the past and also to
learn new things about space and nature that we couldn't have
learned otherwise.
We have other ideas of things we'll see. Supernovas are
rare but they will be wonderful to see. The modelers still
don't know how to make them explode, and we might be able to
answer that question. There are collapsing stars. There are
cosmic stringers. There are defects in space-time. There will
certainly be surprises. There are a lot of things. Every time
we open up a new window to the universe, we see new things and
we're surprised every time. I think this is going to be another
one of those surprises.
Just as we need radio telescopes and optical instruments in
the electromagnetic spectrum to see the full range of
possibilities, we'll also want different kinds of
gravitational-wave detectors in the future. Already underway is
using isolated neutron stars, these funny, magnetized, spinning
stars, looking at their radio signals from neutron stars
throughout the universe, bringing them back down to the Earth
and forming a complete picture of what we see and resolving
that there're ripples in space-time between the Earth and these
neutron stars that may soon yield the result that gives us our
first ideas of what it's like for universe galaxies to be
spiraling together. But really, the ultimate way of doing that
kind of thing sometime in the future would be to have a space-
based antenna. Instead of having two-and-a-half-mile-long arms,
in space you could make two-and-a-half-million-mile-long arms.
Our sensitivity grows with the length of those arms. You could
do phenomenal science that way, and at some point that will be
something I think the scientific community will feel we must
do.
Coming back to Earth, let me say a little bit about LIGO.
Next slide, please.
[Slide]
The first events were only seen with one-third of the full
sensitivity that we believe this instrument currently can do.
Right now, we're tuning it. We're increasing its sensitivity,
and we think that we'll be able to run again sometime in the
fall, making more observations. We're hoping that when we next
run we'll be running with the French-Italian detector, Virgo,
which will be coming on just about that time, and with three
detectors, you can do a great deal more science. You can see
where the source is in the sky and you can get an idea of what
the polarization nature is. It will really add to what we can
learn, and it leverages our investigation to have, as people
were saying, these other projects that are coming along behind
us but will add to, supplement the science we can do and
complement the science we get from our own detectors.
We are the leaders, but with these other observatories, we
will have a worldwide global cooperation that will bring us all
forward in science. Once tuned, Advanced LIGO can go even
further with modest technology changes. We're learning how to
squeeze light, how to get more uncertainty out of our
measurement and improve our resolution by using squeeze states
of light. We also are looking into making better optics, in
particular, ones that have new and better coatings on them that
can reduce noise in certain areas. And it could be at some
point in the future if this field comes alive the way we think
it will, that we'll need a new observatory. It's not there yet,
but that'll happen.
So the window to this new world of gravitational waves has
just been cracked open. As we open it wider, more people look
out on the landscape, we'll be rewarded with discoveries that
will time and time again give us all, scientists, students,
leaders and laypersons, a thrill of understanding things much
better than ourselves.
Thank you for your time. Thank you for your interest in our
science and your continuing support for the spectrum of
innovations in science and technology that we see in the United
States. We hope this glimpse of our field has allowed you to
share in the sense of accomplishment you have enabled.
[The prepared statement of Dr. Shoemaker follows:]
[GRAPHICS NOT AVAILABLE IN TIFF FORMAT]
Chairman Smith. Thank you, Dr. Shoemaker. Thank you all.
Let me recognize myself for questions, and I'd like to ask
quick questions and ask you all to give brief responses if you
could just to get though all these kinds of comments.
But first of all, what are the practical application of
gravitational waves? Dr. Crim, any thoughts on that?
Dr. Crim. Detecting gravitational waves is this
fundamentally inspiring scientific problem, and the point that
Dave was just making about a new window on the universe,
instead of just looking in the electromagnetic region or just
looking at parts from space, we can now look in a completely
different way and see new things, but the practical
consequences of doing this are really what Gabby was talking
about. They have to do with workforce and they have to do with
technology. There are miracles of vibration isolation, and none
of us really believe they're miracles but they are remarkable
efforts at vibration isolation, laser stabilization. All of
those are spinning forward into technologies that are extremely
important to the county.
In addition, the students--and I was very impressed with
your list, Gabby--the students that come out of this are
finding--are not just doing gravitational-wave physics, they
are going on and transforming the semiconductor industry in
SpaceX and many, many others.
Chairman Smith. Thank you, Doctor. You gave several
examples.
Any other examples that anyone wants to mention? Dr.
Reitze?
Dr. Reitze. So I'll follow up a little bit. I actually
believe what Dr. Crim said, that fundamentally, LIGO is about
opening a new window on the universe. Just to give you an
example, after we announced our discovery, the amount of
reaction to it worldwide was awe-inspiring. I learned yesterday
that--I'm not a social-media person but younger people are.
There was 70 million tweets about this discovery which is, to
me, mind-boggling.
I can focus a little bit on the technology to focus on some
of the vibration isolation system. We can't talk about it, but
we've been approached by companies that manufacture, you know,
computer chips that do lithography, and the vibration isolation
that we do, all right, because we have such good low-frequency
vibration isolation, we keep things still for a long time.
That's actually something that could be very, very beneficial
for companies that make semiconductor chips. There are other
examples too that I could talk about but maybe----
Chairman Smith. Okay. Dr. Gonzalez, anything to add?
Dr. Shoemaker then?
Dr. Shoemaker. I have one thing I can add to that.
Timekeeping is really important for a broad range of
activities. I think GPS is one of the things that we most
frequently use now and take for granted. It requires general
relatively to work but it also requires very precise
timekeeping, and some of the innovations that we've made both
in laser stabilization as well as these mirror coatings that
are low loss and low noise, they help us do a better job of
timekeeping, and that really makes a lot of the economy turn,
being able to get things to a place in time.
Chairman Smith. Dr. Reitze, let me follow up real quickly,
and it is this: What can we learn from the LIGO detector--you
mentioned this briefly in your opening statement. What can we
learn from the LIGO detector that we can't learn from
traditional telescopes?
Dr. Reitze. Well, gravitational waves are dark. They're
invisible to the electromagnetic spectrum. So everything we
know about the universe comes from X-rays or gamma rays or
light or an infrared radiation. This is a completely new
sector, so in some sense it's the complete complement of
astronomy, and the event we saw, black holes,we believe that
you can't see them using conventional astronomy, so that's one
example. As David mentioned, cosmic strings. There are a whole
host of things that you cannot learn from any other type of
astronomy that you can only learn from gravitational waves.
Chairman Smith. I probably only have time for one more
question, and let me address it to Dr. Shoemaker, Dr. Gonzalez,
and Dr. Crim as well, and that is, for instance, Dr. Shoemaker,
you mentioned coming surprises. Dr. Gonzalez and Dr. Crim both
mentioned the future. So my two-word question is, what's next?
Dr. Shoemaker. I'll make a guess, and it's a bit of a hope
as well, that it will be a pair of neutron stars spiraling into
each other, which we may actually see also with our ground
instruments. That would be very exciting.
Chairman Smith. Great. Thank you.
Dr. Gonzalez?
Dr. Gonzalez. Let me mention that this discovery of black
holes was a surprise. We didn't know that these objects were in
abundance, and we will now know a lot more about those. So this
was the first surprise. We expect other surprises.
Chairman Smith. You might discover something you're not
even expecting.
Dr. Gonzalez. That's right.
Chairman Smith. Dr. Crim?
Dr. Crim. Your last comment is exactly the point. At the
budget presentation, the Director of the National Science
Foundation, Dr. Cordova, said she wanted to tell us what the
next discovery was but she didn't know because we had to
discover it, and I think that is a very important point. Now we
have a completely new way to look. I mean, to get out of the
electromagnetic spectrum and have the complement of
gravitational-wave astronomy is remarkable.
Chairman Smith. Great. Thank you all for your responses.
The NSF is well represented here today so I'm glad for them to
hear your comments as well.
I'll now recognize the gentleman from Virginia, Mr. Beyer,
for his comments.
Mr. Beyer. Thank you, Mr. Chair.
I'd like to begin by thanking the Chairman and the Ranking
Member for having this hearing. This is great fun. I love this
job just for what we get to learn, and I'd like to welcome the
students from Oakton High School from northern Virginia.
Welcome. It's great to have you guys here.
I feel like I'm in Bern, Switzerland, in 1905 or the United
States in July 1969. This is just so exciting. And I have
some---forgive me--nerd questions for you guys, and I'm not
quite sure who to send them to.
So we have the strong nuclear force with the glue on and
you have electromagnetic force with the photon and the
gravitation force is supposed to have the graviton,
gravitational waves and graviton wave particle, so tell us
about the graviton.
Dr. Gonzalez. The graviton is actually the particle nature
of gravity. What we detect with our detectors is the wave
nature of gravity. Those are the gravitational waves. So it's a
classical version. Each of these gravitational waves we
detected and the ones that----
Mr. Beyer. Will you be able to find something like the
photoelectric effect with the gravitons?
Dr. Gonzalez. Probably not with LIGO detectors, no.
Mr. Beyer. Okay.
Dr. Gonzalez. We do not do quantum gravity. That is
actually a very hot area of research but we do classical
relatively, which is interesting enough.
Mr. Beyer. Okay.
Dr. Reitze. To follow up on that, so we actually calculated
how many gravitons we saw or how many gravitons were released
in this experiment or in this black-hole collision, numbers 10
with 80 zeros after it, so there's a huge number of gravitons
here. We may discover something. I might--we may discover
something interesting about quantum gravity that we didn't know
before. That's one of the excitements of this business.
Mr. Beyer. Does the gravitational waves go at the speed of
light?
Dr. Reitze. Yes. That's what we've learned in this
experiment, that we've put a limit on it, that it can only--it
can't go slower than .992 or 993, the speed of light. We
believe it goes at the speed of light.
Mr. Beyer. So we didn't know that these black holes existed
or were about to collide until we saw the gravitational waves
from then, and imputed that backwards?
Dr. Gonzalez. Yes.
Mr. Beyer. Very cool. So Einstein spent most of his life
hating quantum mechanics and trying to reconcile quantum
mechanics with general relativity, reconciling gravitation
force with the electromagnetic and the strong force. Does this
help?
Dr. Reitze. Actually it's interesting. Einstein, first of
all, he goofed when he calculated the first gravitational-wave
phenomenon. He actually got the term of the radiation wrong. He
corrected that and fixed it, but later he actually believed
that the--first of all, the effect was so tiny that it would
never be discovered, so he never worried about it, and then
later he actually believed that it didn't really exist and he
had to be convinced by one of his postdoctoral associates that
it exists. So Einstein himself doubted his own discovery.
Mr. Beyer. But will--Dr. Crim, will the reconciliation
between quantum mechanics and general relativity come about?
Dr. Crim. Well, we're certainly funding researchers who are
working hard on pushing the theory and pushing that
understanding. That's a great, outstanding question in physics
and in science today. But it's interesting to think, if we
think about--you mentioned the photoelectric effect. The things
that gave us hints about quantum phenomena were people looking
for often electromagnetic radiation to behave classically. So
as we now have the ability to look at gravitational radiation,
just as my colleague said, there may be a surprise lurking in
there as we go and with this tool start to poke on that
behavior.
Mr. Beyer. The cosmologists try to look as far in time in
possible and, you know, we have that initial thousandths or
millionths of a second that we can't see. Does gravitational
waves help us to get back to there?
Dr. Shoemaker. We can say that it's unlikely that LIGO with
a ground-based observatory will have a chance to see the
primordial gravitational-wave background. At least our
predictions right now insofar as we understand it would put
them at a level which is too low to be seen, but it could be
that either a space-based antenna could be seen--could see
these sorts of effects or these ground-based antennas, which
have been looking from Antarctica to try and understand the
polarization of the Big Bang background, I think those
experiments will also give a positive result shortly. I hope
they will. That will be a very exciting result.
Dr. Gonzalez. And let me say that one of the questions that
people are drawing--one of the conclusions they're drawing from
our observation is how early or how late the black holes
formed. That is not well known at this point, and our
observations are the ones giving clues about the origin of the
small black holes.
Mr. Beyer. Dr. Reitze, one last question. String theory,
yes or no?
Dr. Reitze. Maybe.
Chairman Smith. Thank you, Mr. Beyer.
The gentleman from California, Mr. Rohrabacher, is
recognized for his questions.
Mr. Rohrabacher. Thank you very much, Mr. Chairman. I've
got a wild question at the end to ask you, but in the meantime,
let me do some business here.
We started off this program with a $300 million grant in
1980. Is that correct? Okay.
Dr. Crim. Ninety-four was actually when that was made.
Mr. Rohrabacher. Okay. So--okay. I thought that you said it
was 1980. In 1994, was the first major expenditure of $300
million?
Dr. Crim. That was when we went to the phase of actually
constructing LIGO but these earlier dates where we're talking
about funding research starting in 1979 had to do with a lot of
demonstrations of both technology and science. For example,
people built tabletop laser interferometers to start to show
that they could reach the kinds of sensitivities--there was a
chance to get there. My colleagues here can tell that story in
some detail but this is a pattern that we often follow. We
start out funding folks who lay the groundwork and then the
community gets together, again as my colleagues said, and makes
a compelling argument based on that early theory and
experiment.
Mr. Rohrabacher. Okay. So from those early experiments
until now, how much are we talking about that's been spent on
the project?
Dr. Crim. We have spent a total of over a billion dollars,
$1.1 billion. About $450 million of that went into actually
constructing initial Advanced LIGO. The rest has supported
operations and maintenance of the observatories as well as
individual investigators that were doing that early kind of
work and the laboratory work I'm talking about.
Mr. Rohrabacher. We talked about everybody's working
together and many different countries have contributed. How
much have they contributed to this effort?
Dr. Crim. David, why don't you comment?
Dr. Reitze. So Japan got started with a detector in the
1990s, and they're building a big one. I think their number,
don't quote me on this, but I think it's on the order of 250
million, but they're well behind us.
Mr. Rohrabacher. The Japanese, you say?
Dr. Reitze. That's the Japanese detector. The Italian Virgo
detector, I think they're in--the way they do their accounting
is a little bit different because they don't cost their people
in it so it's not really an apples-to-apples comparison but
probably they have spent about $200 million not including the
people that they've put into it.
Dr. Crim. It's foreign countries----
Dr. Reitze. Oh, I'm sorry. Maybe I misunderstood the
question. Foreign contributions to Advanced LIGO--David
Shoemaker might be able to answer that question.
Dr. Shoemaker. Let me speak to that. NSF did fund us for a
program to build Advanced LIGO detectors at $205 million, but
then of their own free will, the German Max Planck Society, the
STFC in the U.K., and also ARC in Australia all made
contributions with a total value of some $17 million just
because they wanted to be part of the experiment. They would've
had access to the data. They would have enjoyed the profits of
it. They wanted to be part of this activity.
Mr. Rohrabacher. So would it be fair to say we've spent
about half the money that was necessary for the project to be
successful as you are today, and the rest of the world spent
half of that, and----
Dr. Shoemaker. No, our fractional contribution is much
larger than that, but as far as getting to the point of this
observation, it is sort of 20 million versus 450 million of
construction costs but Dr. Reitze was making an important
point. Other nations are mounting large gravitational-way
detection elements and we are working in concert with those. So
if you wanted to add up all of that, the money going into
KAGRA, the money that's going into Virgo, that becomes a much
bigger number, but as far as the U.S. investment in these
instruments, it's about what I said.
Mr. Rohrabacher. I've always supported basically research
when we're looking out because I've been told that if we're
looking out into outer space that we actually can determine
what's going on in the molecular structures that can have
impact, major impacts here, and sometimes it's easier to see it
out there than it is to see it through your little microscopes.
Telescopes and microscopes are very related from when I was
first educated when I first came here, so I've tried to be
supportive of both efforts.
Now let me ask a little--I know this--Mr. Chairman, just
one--first of all, we're talking about waves, and I'm a surfer,
of course, and I want to find out about riding waves, but will
this discovery that you are talking about today make time
travel any more--I mean, this is one thing I've been hearing
about. Will it make it any more likely?
Mr. Loudermilk. Beam him up, Scotty.
Dr. Gonzalez. We wish. This actually does show distortions
of space-time so we measure it as distortions of distance but
it is distortion of time. We can see time traveling faster and
slower but it cannot make us travel in time.
Mr. Rohrabacher. Well, thank you very much.
Chairman Smith. Thank you, Mr. Rohrabacher.
The gentlewoman from Connecticut, Ms. Esty, is recognized.
Ms. Esty. Thank you, Mr. Chairman, and to the Ranking
Member, and most of all, thank you to the four of you and these
huge, exciting team of international researchers. So there are
two topics I wanted to quickly touch on. First was the
importance--and you've all mentioned it a little bit but the
importance of robust, long-term funding for basic research. You
know, if we're going to break those boundaries, reach beyond
what we know, it does take that kind of serious long-term
committed investment, even in the face of if not failure, not
the sort of data you would have wanted. So a couple of you can
comment on that because we're under constant budget strains,
and it's really easy for people to say, you know, I have
bridges and roads and schools in my district that need fixing
but I also believe that we will be better not just as a country
but as a species if we continue the sort of cutting-edge
research. So that's one topic.
And the other was to talk a little bit--and Dr. Gonzalez,
you particularly touched on this--about the diverse STEM
workforce and the need to inspire a new generation, the
collaboration that comes up, and what efforts are being taken
in this project to make sure we're seeing diversity because I
know, you know, a suburban white boy may be thinking about
using those STEM skills differently than a woman of color in
the inner city, so hoping that we're really making an effort as
part of this collaborative endeavor. Thank you very much.
Dr. Shoemaker. Let me say one or two things about
discussion of the sustained support for the research. I'm a
professional scientist, I'm not a faculty member, and it's been
really invaluable for me and for other colleagues in the LIGO
Laboratory supported by the National Science Foundation to be
able to turn our careers to this and choose to, without
striving every 6 months to look for another funding source, to
be able to make plans, to be able to make small-scale
experiments that take years to give results, to work with
industries in a cooperative way through the manufacturing
cycle. It's that kind of continuity and intellectual input that
allows something of this nature to take place. So that's been a
very, very important thing to us. Clearly, also, when students
come to us and say they want to do a project with us, and we
can tell them you're going to be able to start and finish on
this topic. It's something that really gets people engaged,
keeps their mind on the science and away from what's happening
next, so it's been very valuable to us. Thank you.
Dr. Gonzalez. I have to say that it's not only us as
members of this collaboration that are inspired to work on this
because of black holes and gravity and Einstein, we inspire
people too, and we have made a very big effort, we have a big
effort in outreach and diversity. We actually try very hard in
the United States to increase diversity, not just of our
collaboration but of the scientific workforce in general. We
work with the National Hispanic Society of Physics, with
National Black Society of Physics. We have fellowships that we
work out with them. So we do have a very diverse effort.
But it's been rewarding with this discovery, especially to
receive questions and visits, visits from schoolchildren, from
parents wanting their children to learn about the science. We
receive emails all the--all day from many schoolchildren asking
about gravity and Einstein and how do you do this and where is
this done and how can I visit. It's inspiration that we provide
that I think it is--it's going to help the diversity of our
workforce.
Ms. Esty. And to that point, if you have not already, I
would hope that you are developing materials, links to websites
that you can disseminate us to, we can to our districts and to
our colleagues to allow that citizen exploration and
inspiration because we find obviously the ability to use the
internet really does bring this home, and I can tell you we had
the astronauts here in a live link in this room, and I was able
to have a live link with an astronaut from my district, and the
inspiration for 3,000 school students who could watch a
graduate from their high school speaking to them while he's
spinning upside down was extraordinary, and I would hope--this
has really captured the Nation's imagination so I urge you to
develop good materials of a variety of ages and then we'd love
to--I know I would, and I know all of us would love to be able
to make that available to the students and----
Dr. Gonzalez. We are working very hard on that. We already
have a K-12 material about this discovery, and we also have
translations on our website and our papers in different
languages including Spanish.
Ms. Esty. Terrific. Thank you very much. I really
appreciate your hard work, and another 40 years for this
project. Thank you.
Dr. Crim. If I could----
Ms. Esty. Dr. Crim, yes.
Dr. Crim. --briefly comment to two of your points. Our
Directorate for Education and Human Resources has been
collaborating with us and generating the kinds of materials
that you're talking about. We began thinking about that prior
to the announcement and conversations with the leader of that
directorate, Joan Ferrini-Mundy.
Your comment about long-term sustained funding and what
David had to say about it is really important. We see ourselves
trying to find ways to support these long-term risky bets to
really get out on the edge and do something transformative, and
I think we all recognize the challenges that--with the budgets
the way they are but we see that as a constrained, a boundary
condition within which we work, and we try what we can to
accomplish what David was talking about to let these projects
have the stability. It's not easy. It's a constant dynamic
tension.
Ms. Esty. Thank you all very much.
Chairman Smith. Thank you, Ms. Esty.
The gentleman from Florida, Mr. Posey, is recognized for
his questions.
Mr. Posey. Thank you, Mr. Chairman. Thank you for holding
this hearing, and I want to thank all the witnesses for their
participation on this exciting subject.
For Dr. Reitze and Dr. Shoemaker, because the expansion of
the universe is accelerating, I'm told that the science
theorized a mysterious dark force is pulling us apart and that
only five percent of the universe is visible to us. They say
dark matter is 27 percent and dark energy is 68 percent of the
universe. That's just what I read. Can the gravitational waves
help us understand the missing dark matter and the dark energy
better?
Dr. Reitze. So let me start, and David can comment. It may
be possible--first of all, gravitational waves themselves
exist. They're ubiquitous just like dark energy and dark matter
but they're a very, very tiny fraction. I mean, you can sort of
add up how much energy density is in from gravitational waves
and it turns out to be very tiny. But it may be that
gravitational waves interact with dark matter in a way that we
haven't theorized yet or calculated so it may very well be that
somebody will come up with an idea to use LIGO or maybe LISA,
the space-based detector, to detect them. So it is--you know,
it's one of those things where now that we've detected
gravitational waves, people are going to start thinking about
how can we use to understand other more fundamental things.
Dark energy is trickier. I once heard somebody say that
dark energy overstates our knowledge of this phenomenon by two
words: dark and energy. We really don't even know what--it's
getting--there's getting better understanding of it but it's
still--you can measure it but to understand it is kind of hard.
Dr. Shoemaker. Let me add that we're already one step along
the way by having seen just how well our discovery, our first
discovery, matches general relativity. It is astonishing how
well Einstein's theory from 1916 matches what we saw, and that
already excludes some possibilities for some things going
haywire in our understanding of the universe. So that's already
a set of constraints, and we think as we see each new source,
we'll probably reach new limits. Maybe we'll discover something
which is different than we expect, and that would really be a
key, or maybe we'll find that our theories are better and
better confirmed, but either way, this new window on the
universe gives us a possibility to close some opportunities
that would otherwise not be there to zero in on what the real
answer is.
Mr. Posey. You know, if it took 100 years to go from
Einstein's equations to discovering they're actually correct,
just wildly thinking, what do you foresee in the next 100
years? And all of you just comment on that if you don't mind.
Dr. Reitze. So my favorite philosopher is a gentleman named
Yogi Berra, and he said predictions are difficult, especially
about the future. You know, you can look back 100 years ago
when general relativity was first postulated, when quantum
mechanics were first postulated, and it was--at least it would
have been impossible for me to project forward where we might
be. That's the thing about science that's so great, that you
never know where your big breakthrough is going to come from.
So for example, you know, everybody probably or some people
have been through MRI, you know, getting diagnostic imaging
from MRI. That comes from an obscure phenomena that was
investigated in the 1940s and 1950s by nuclear physicists and
condensed-matter scientists so I wish I could answer. If I
could, I would probably make a lot of money in the stock market
but I just don't know.
Mr. Posey. We love wild speculation in this Committee, and
that's just what Einstein was 100 years ago actually.
Dr. Gonzalez. Let me say that I also don't have an
imagination big enough to think what will happen in 50, 100
years from now, but I think there are surprises that are a lot
closer. We are looking at the dark side of the universe. You
talk about dark matter, dark energy. We are looking at the dark
side, black holes of which we know very, very little. These
surprises are just around the corner. That's what I imagine the
best side of this story is.
Dr. Crim. I want to emphasize how well chosen your time
scale is in that it can take 20, 50 or 100 years for these
discoveries to come out of ideas that start to emerge now and
the consequences can play out over those time scales.
Dr. Shoemaker. I don't have too much to add. I'm an
instrument builder. I love the technologies. I know we'll be
doing wonderful things with the technologies that we're
developing 5 or ten years from now. What will happen 100 years
from now, I have absolutely no idea, but it will be neat.
Mr. Posey. And finally, Dr. Crim, I was wondering as the
field of gravitational-wave astronomy moves forward, how are
the NSF and NASA corroborating on supporting the field?
Dr. Crim. We have a very effective and close collaboration
with NASA. The simple way to describe it is, we do ground-based
astronomy; they do space-based astronomy. But that means that
oftentimes experiments we fund are very complementary to ones
they fund. For example, we have a collaboration on their
exoplanet program making ground-based radial velocity
measurements to understand the mass of planets around other
stars. So we have joint committees where we talk constantly,
and the physics and astronomy that unites this effort is common
to us both, and we're in really good contact.
Mr. Posey. Thank you.
Thank you, Mr. Chairman.
Chairman Smith. Thank you, Mr. Posey.
The gentleman from Illinois, Mr. Foster, is recognized.
Mr. Foster. Thank you all again.
And just in terms of technology, I bet you have some fun
facts about your mirror specifications and how that compares to
the sort of mirror that you look at every day in the bathroom.
Dr. Shoemaker. Well, I've actually never done any metrology
on my bathroom mirror and so I can't quote you the
specifications for it. The optics which are hanging freely in
space to respond to the passing gravitational waves are right
circular cylinders. They're chunks of beautiful, clear fused
silica, or glass. They're about 100 pounds each. They're
about--they're 34 centimeters, about a third of a meter, about
a foot and a half in diameter. Their surfaces are polished to
the radius of curvature that matches our two-and-a-half-mile-
long arms so they're actually a very, very shallow curve and
figured to within a ten to the minus 9 of a meter across or ten
to the minus 10 of a meter across the full surface. This is
work done by Zygo et al and they developed these techniques I
think for some satellites that are looking down on us at the
very moment. But they were able to figure these mirrors to an
absolutely superb precision and then on that we put down layer
after layer of alternating indices of refraction to get mirrors
which reflect the light back extremely effectively with very
little absorption but then also a curious additional
requirement that the mechanical losses in the coating be low.
This is part of the thermal noise. It's like the Brownian
motion. Everything is jiggling around because it's at room
temperature. Our coatings are the things that jiggle the most
in our entire interferometer, and it's there where we have to
put the most work in the near future in making our technology
advances, and those are tough ones to do.
Dr. Reitze. And let me just follow up on that. This is
where LIGO is so cool in so many ways for me. This is--the
problem that David just alluded to is a material-science
problem. You know, we have to solve fundamental material-
science problems to be able to discover black holes so there's
just a natural connection across lots of different disciplines.
Mr. Foster. Thank you. So cooling the mirror is not going
to get around the coating problem?
Dr. Shoemaker. It would work. In fact, the Japanese
detector, KAGRA, which is in the process of now going together,
uses this technique of cooling mirrors. The noise goes down as
the square root of the temperature and so it's a pretty hard
row to hoe. You have to bring down the temperature of a lot of
big equipment in the presence of a very intense laser beam, so
it's a big challenge. It's going to be somewhere in our future
but I think we can do a lot on the Earth with the LIGO
infrastructure without getting into cooling, and I hope we can
hold off on the cooling until we really know that it's the best
path to take. It's complicated.
Dr. Gonzalez. But let me say that like Dave said, this will
take fundamental research in coating technology that it's not
in hand yet. Advancing our detectors, improving--we can improve
the detectors. We have technology already to improve the
detectors a bit but to improve them ten times better, we have
to make them 10 times longer or get technology for these
coatings 10 times better.
Mr. Foster. And what do you think are the ultimate
capabilities of ground-based versus space-based and what are
the sort of sources that you can hope to see with each? And in
particular, what would it take to get to the sensitivity where
you could have seen SN1987A, the supernova that was detected in
my--the detector built for my Ph.D. thesis?
Dr. Shoemaker. Let me say a little bit about the technical
limits on the ground. What we'll probably find ourselves
limited by is the lowest frequency we can observe which also
corresponds to the biggest system of masses that we can
measure, and it's finally the fact that the Earth is not just
moving but also compressing and getting less dense as seismic
waves pass that causes our mirrors to move because the amount
of Newtonian attraction of the mirror is changing as a function
of time, and that's a wall that's about one hertz and that will
limit us to, I don't know, something like a thousand solar
masses as the biggest objects that we can really measure on the
Earth, and at that point it will really be the time to go into
space and see what's going on there. The others, if you want to
respond to the other questions?
Dr. Reitze. Yes. If the supernova 1987A went off today and
LIGO was on line, we'd have a good chance of actually seeing
it. We would have actually seen it. Or if we didn't see it, it
would've said something about the dynamics of the core collapse
in that supernova process. So there's a star Beetlejuice that's
a red giant and it's probably going to explode sometime in the
next 10,000 years. We're hoping it explodes in the next--we're
hoping it's already exploded and the signal's on its way----
Mr. Foster. Do you have any graduate students where that's
going to be their Ph.D. thesis?
Dr. Reitze. They're lining up in 2028.
Dr. Gonzalez. But let me say that the sensitivity to
supernova is on the high-frequency end as opposed to the low-
frequency end, and the coolest technologies that we will be
applying is quantum manipulation of the light that will improve
our sensitivity to supernova.
Mr. Foster. And so do you have an easy way to explain to
this Committee what squeezed light is?
Dr. Reitze. Sure. So--I'm sorry. These are questions we
love, okay, and shut me up if I'm getting--I'll be quick.
So electromagnetic waves are not very precisely defined.
They have uncertainties in amplitude and in phase, all right,
and that comes from the natural quantum nature of light, and
the way that you distribute those uncertainties, somebody named
Heisenberg told us that there was sort of a little fuzz ball.
You can think about an electromagnetic wave as a vector with a
fuzz ball at the end. You can actually squeeze the amplitude at
the expense of phase or vice versa. So this is something that's
existed since the 1980s and it's actually a technology that
hasn't found much of an application until LIGO, and now we're
using it, so----
Mr. Foster. Thank you. I yield back.
Chairman Smith. Thank you, Mr. Foster.
The gentleman from Kentucky, Mr. Massie, is recognized.
Mr. Massie. Thank you, Mr. Chairman.
My first question is, how frequently do these observable
events happen? You know, like when we talk about storms and
floods, 50-year storm or a 50-year flood, 100-year-flood, this
event that you observed from probability, how soon can we
expect to see one of that magnitude or larger again?
Dr. Gonzalez. Very soon. We----
Mr. Massie. Like five minutes or five decades or----
Dr. Gonzalez. Well, let me tell you, the analysis that we
presented was the analysis of one month of data taken with the
two detectors that only had 16 days of effective time when the
two detectors were working together and we need the two
detectors to confirm the signal, and we saw one event in one
month. Of course, you could say you can----
Mr. Massie. Well, that either means you got really lucky or
your instruments aren't working, or it could mean a lot of
things so----
Dr. Gonzalez. That's right. That's right. So we can only
predict from that one month of data. We can only say we saw one
event in one month. But we have taken three months more of data
that we are still analyzing, and everything we see is
consistent with what we saw there, and we are going to take
more data in the future, and from the theories that we derive
even from this just one observation, we have a predicated rate
that will mean at least a few a year.
Mr. Massie. Dr. Shoemaker, you're from the university I
graduated from so----
Dr. Shoemaker. Oh.
Mr. Massie. --go ahead.
Dr. Shoemaker. So one other thing to point out, though, I
mentioned that we're at one-third of the sensitivity we believe
our instruments can achieve with just doing tuning. A really
neat thing about gravitational waves, it's an amplitude
phenomenon. It falls off as one over R and not over one over R
squared, the distance from the source to us. If we can increase
our sensitivity by a factor of two, the number of sources
within reach goes up as two cubed.
Mr. Massie. So I was going to ask you about that. You said
it's going to increase by a factor--or it's going to increase
by three. Did you mention 3X or three orders of magnitude?
Dr. Shoemaker. I mean 3X.
Mr. Massie. Okay.
Dr. Shoemaker. That's to say we'll reach----
Mr. Masie. Darn.
Dr. Shoemaker. --three times further out, but that means
that the effective--sorry. That means the effective rate will
go up by 27 if you cube three, and if we saw one event in 30
days of observing, that says we might get to the point where
we're seeing an event every day if this one event we saw is
representative of the rate. So I think we can see that there's
a lot of progress in the future----
Mr. Massie. Right.
Dr. Shoemaker. --that can go to increasing the rate.
Dr. Reitze. And that's just for binary black holes. We
still haven't seen neutron stars, and we expect to see quite a
few of them per year when we're at design sensitivity.
We talked about supernovas before. They are the ones that
are going to be hard to see. We're going to have to get really
lucky to see a supernova because they're just not that strong
of an emitter.
Mr. Massie. One of the questions I did want to ask, and Dr.
Gonzalez, you touched on it. Did you remember to leave it on
when you came to the hearing? Like what is the duty cycle? How
frequently is this collecting data, and maybe we've already
observed things we don't even know yet and people just need to
sort through that data. Maybe we've already observed
simultaneously something that we saw in the electromagnetic
spectrum but we just don't know it yet. Is this thing turned on
now?
Dr. Gonzalez. It is intermittently, but for diagnostic
purposes, we have not taken data in coincidence but we have
plans to take more, what we call engineering runs,
opportunistic engineering runs. We have another run with the
two LIGO detectors starting in this late summer, early fall,
perhaps July, and that's how we will know what the rate of
these binary black holes and perhaps other events will be.
But let me say, you asked me if I remembered to leave it
on. It's not me, and that's the strength of having a thousand
people working on these. We have 200 people in the LIGO
Laboratory and they are the ones who not only keep the
detectors on but they improve them every day.
Mr. Massie. I have a question I want to make sure I get to
ask. What are the sources of noise that you have to contend
with? You know, like I imagine our sun is doing something.
There may be nuclear tests where on Earth that are causing
seismic. Maybe talk radio is interfering. It's a big source of
noise. But what are some of the noises you'd have to filter
out?
Dr. Shoemaker. Let me say what the basic noise sources are.
One of them has to do with the sort of quantum effects that
Dave Reitze was talking about. We use lasers, and the lasers
emit photons in a statistical way so there's a fluctuation of
the number of photons so there's a fluctuation in what we use
as our measure of where the masses are.
Mr. Massie. Can you get smaller photons?
Dr. Shoemaker. The thing to do is get more photons, turn up
the laser power. The next thing to do is address these
questions of thermal noise that I mentioned earlier on, that
everything is jiggling around due to Brownian motion, and the
way we address that is to choose materials that have very, very
low internal losses and squeeze all of that jiggling into a
very narrow frequency band.
Lastly, you were talking about seismic motion. We built--
and that's one of the really big improvements of Advanced LIGO
over Initial LIGO, a system of seismic isolation which makes it
so that we're effectively independent of the environment around
us during normal weather conditions. We still can get knocked
out of lock when there's a lot of wind. There was a tornado
down in Louisiana just yesterday. So there's----
Mr. Massie. One last quick question before I yield back.
When you get this third detector, does that just improve the
reliability of your data or does having a third point on Earth
give you an ability to triangulate? Dr. Crim, you were shaking
your head. Maybe you could----
Dr. Gonzalez. All of the above.
Dr. Crim. All of us are shaking our head yes. That's----
Dr. Gonzalez. To both.
Mr. Massie. But will it give you a bigger picture of what's
going on? Can it do that?
Dr. Gonzalez. It gives you better localization so you will
better pinpoint what the source comes from, but also if you
have three detectors, you need two to see a signal. If you have
three, you can have one on and the other two and then you will
still see the signal. With only two LIGO detectors, if one is
down, we are in the dark.
Mr. Massie. Thank you, and I yield back. I could ask a
hundred more questions. This is very fascinating. Thank you.
Chairman Smith. Thank you, Mr. Massie.
The gentleman from New York, Mr. Tonko, is recognized.
Mr. Tonko. Thank you, Mr. Chair, and welcome to our panel.
What a fascinating panel. Let me congratulate you and all the
people and institutions who have inspired this tremendous
moment. It's truly a phenomenal success, and certainly I'm
grateful to the people who had the vision and pursued based
upon the seed that they planted to be determined to come to the
success that we've met. So I anxiously look forward to what
else is out there, and you know, and can't wait to see what is
yet to come. And if this doesn't serve, if this doesn't
illustrate the value added of high-risk, high-reward basic
research, I don't know what does. So hopefully we get the
message, we invest deeply and soundly in research and move
forward.
My question would be to all of you, any of you, what role
did partners in industry play in the design and development of
the--of this new technology? Certainly you've got
infrastructure that we've seen in your slide presentations.
There was a lot of talent you had to draw upon, so can you
describe that, please?
Dr. Reitze. Just a couple of examples. I'll start actually
with the first LIGO, Initial LIGO, which was built in the late
1990s and 2000s. We partnered closely with a firm called
Chicago Bridge and Iron Works that developed our vacuum system,
and this was a--this vacuum system at the time was the world's,
I think, largest although maybe that's not true from a defense
standpoint, highest vacuum system, and some of the work that
they did for us went on to later inform what they did for the
National Ignition Facility.
We worked closely with a company in Silicon Valley that
developed layers, Light Wave Electronics. They developed the
first laser for Initial LIGO that was actually used in some
other applications such as newspaper printing.
As David mentioned, we worked closely with industry for
developing optics and coatings so that's both in the United
States and in with international partners. We worked a lot with
companies in Colorado, in Boulder, Colorado, to develop some of
the first LIGO mirrors and some of the first coatings, a
company called Research Electro-optics, also advanced in films.
We work a lot with companies like Invidia, all right, because
we use graphic--we use GPUs in some of our analyses. We're
actually not using them right now but we will be using them so
we'll working closely with them. So there're a number of touch
points where we've actually worked--partnered closely with
industry, and that's just a partial list.
Mr. Tonko. Right. Anyone else that----
Dr. Shoemaker. That covers a broad spectrum of the things
that we used.
Mr. Tonko. Was there anything unique in the collaborations
that you developed as a LIGO industry? Was there anything in
particular that was a different approach?
Dr. Reitze. We developed--actually, this is one of the
things that I worked on. We had to develop some novel electro-
optic technologies for--it's sort of a technical thing about
how we lock--how we keep our interferometer in an operational
point. We had to develop something called electro-optic
modulator that was actually new and it's patented. It hasn't
been licensed--it hasn't been licensed yet. But there are
things like that. Some of the work that we did with the silica
fibers, I think, with the Glasgow group has been spun off to
some other applications.
Dr. Shoemaker. Then coming back to the mirrors once again,
we knew what we needed for mirrors and so we found the very few
bidders, one in Australia and one in France, by the way, who
could deal with our basic requirements but they couldn't
actually even measure what needed to be measured, and so we
gave them instruction on how to proceed. We worked with them in
a collaborative way to develop the technologies that were
necessary and then we brought the optics back to Cal Tech where
the very finest metrology in the world could be done and give
them feedback about what they need--you know, what kinds of
changes they needed to make in their technology. So in that way
we were able to trade things back and forth between the
academic side and the commercial sector and work in a
collaborative way to get something to push the state-of-the-art
forward.
Dr. Gonzalez. I should mention also that information
technology has been used. Many of the algorithms or some of the
algorithms that we developed to search for gravitational waves
in the data have been--have found applications in the genomics
industry and in some other Big Data analysis, and that's why
some of our graduates actually are sought by these industries.
Dr. Shoemaker. In particular, the kinds of challenges that
we have of looking for small, intermittent signals against a
complicated noise background are things that the defense
industry finds interesting, so a number of people have gone off
into that sector and discovered the skills that they developed
with us were very useful. We don't hear much back from them,
though.
Mr. Tonko. Well, it just shows the emphasis that we have on
science and engineering, scientists and engineers to make it
all happen.
And just quickly, Dr. Reitze, you made mention of the
commitment of NSF to fund the development of LIGO as a
scientific moon shot. Can you elaborate upon that?
Dr. Reitze. Yeah. Look, I think Chairman Smith said it, or
somebody said it quite well, that the first time people,
rational scientists hear about LIGO, they think it's crazy
because they think how do you possibly make a device that can
measure to the billionth of, one- one-billionth of a diameter
of a proton, and you scratch your head, and then you start
thinking about it and you realize that yes, it is possible. So
in some sense, this was even bigger than the moon shot in the
sense that I think most physicists--and it ran into resistance
early on. Most physicists didn't believe it could be done. So I
think it was due to a few key people including some key NSF
Directors early on, Rich Isaacson and Marcel Berdon, that
recognized that yeah, you could do this. It was just amazing.
Dr. Crim. Just to briefly follow up on that, this is not a
discontinuous process as people scratch their heads, they do
calculations, they do experiments, and you persuade people.
It's a very critical community competing for precious
resources, and people have to make their case forcefully,
persuasively, and part of what we try to do at NSF is to
balance off all of those really good ideas, and it's a
marketplace where people have to really meet a very high
standard, and this wasn't some longshot, it was a series of
considered bets, and they were risky but it's paid off
beautifully.
Mr. Tonko. Well, thank you, and again, congratulations, and
with that, Mr. Chair, I yield back.
Chairman Smith. Thank you, Mr. Tonko.
The gentleman from Georgia, Mr. Loudermilk, is recognized.
Mr. Loudermilk. Well, thank you, Mr. Chairman, and this is
very exciting. It's a very exciting discovery, and I'm very
proud that we discovered this here in America. This is the type
of thing that we have been known for in the past, and I think
it's large in part not just to investment but to the freedom
that we have to investigate and explore.
And again, I see it much like the Apollo program that some
of the spinoff technologies that we're going to have not just
from the discovery itself but the tools and the technology that
goes into the discovery I think is going to benefit future
generations.
I've also been impressed with the large audience we've had
here today, Mr. Chairman. I think this may be one of the
largest audiences that we've had, and I really appreciate those
students being here. This is the type of thing that I think
we're setting the groundwork for future generations.
In Georgia we've had a little bit of a challenge of
inspiring our young people to get into science and technology
career fields. We have some of the world-class research
institutes right there in Atlanta. We're leading the Nation in
health IT and a lot of innovations and discoveries but yet our
biggest challenge has been filling those jobs with innovators
just seemed to be a lack of inspiration. But I'm becoming more
encouraged by what I see here and something I did yesterday. On
my way to the airport, I had the opportunity to stop by one of
our high schools and notify two students, both high school
sophomores, that they had won the app challenge that Congress
had put on. Ryan Cabelli of Kennesaw Mountain High School and
Alvin Potter of Wheeler High School took technology--they
didn't develop the technology, the coding language, but they
saw a need with other students and they took the technology
someone else had discovered and they put it into a practical
application called Grade Spar. As they informed me that GPA is
everything to these students and one of the challenges students
have is predicting what their GPA is going to be based off of
their previous grades. So they have actually developed an app
for your phone that students can put their grades in and they
can estimate where their GPA is going to be and what they need
to do, and so it's taking the research others have done and put
it to a practical application, which I think this next
generation will be able to do that same thing.
A couple of questions, though. I'm very interested in the
technology you're using. I spent 30 years in the IT sector--but
the technology that you use to actually do these discoveries.
But first of all, from previous questions, I was very intrigued
about what you've discovered about gravity, that from what I
understand, it sounds like there's a lot of properties of
gravity that's very similar to light, the speed, that there is
actual waves, and particles. Are we seeing more and more
relationship between the two the more you discover?
Dr. Gonzalez. Well, yes, of course. There is a very strong
relationship between the sky, what we learn about the sky from
the electromagnetic and the gravitational spectrum. I think one
of the biggest--I wouldn't say surprise because we are
expecting it--one of the biggest events that we expect in the
future is seeing a bright source both in the electromagnetic
and the gravitational spectrum so that we can learn from the
matter and the photons in there. That will be amazing. And it
will happen. It will happen soon enough.
Dr. Shoemaker. But then on the more fundamental question of
the similarity of the two different effects, it's true that in
both cases it's information that travels at the speed of light
or the speed of gravity as you prefer. In both cases, the
effect is perpendicular to the direction of propagation of the
effect. In both cases, as you make antennas longer under the
conditions of long wave lengths of information, you get bigger
and bigger signals.
A basic difference, though, is that a photon is a particle
that travels in space time. And we looked at space time itself
as it warped, and so it's a slightly different thing in that
sense there.
Mr. Loudermilk. So as we get to the longer tubes, if I may
ask--I know I'm running out of time--are you already seeing
the--anticipate even at 4 kilometers you're seeing the
gravitational pull on your lasers--a slight, somewhat bend of--
--
Dr. Reitze. Yes, we see actually--so we design our
instruments so that the light itself--4 kilometers is not a lot
of distance----
Mr. Loudermilk. Right.
Dr. Reitze. --distance for light, and we have to design our
instruments so that we take into account the curvature of the
Earth----
Mr. Loudermilk. Right.
Dr. Reitze. --so that we can go flat. But what we do see in
our instruments are the tidal effect from, you know, the moon
goes around the Earth, the Earth, you know----
Mr. Loudermilk. Right.
Dr. Reitze. --the Earth sort of breathes because of the
tidal effects, and that actually shows up on our detectors. It
changes the length of our detectors by about 100 microns a day.
And we actually have to----
Mr. Loudermilk. Okay.
Dr. Reitze. We predict it. We can correct for it and we
feed it back so that we don't have to----
Mr. Loudermilk. Well, that was kind of my other question as
far as the calibration factor from seismic activity and having
the thought about the effect of the gravitational pull on the
moon. So there is a lot of technology, as you alluded to, just
to go into the research itself, and I applaud you on these
great discoveries. Thank you.
Chairman Smith. Thank you, Mr. Loudermilk.
The gentleman from Colorado, Mr. Perlmutter, is recognized.
Mr. Perlmutter. Thanks, Mr. Chair. Just a couple questions.
I find this so fascinating and so over my pay grade I don't
know what to tell you. And you four really are inspiring to me.
You talked about being inspiration to your students. You're
inspiring to all of us. And thank you for your patience and,
you know, looking at this and talking about the space time
continuum and warp speed and worm holes and I don't know what
else. But just sort of just the basic human question for me is
like can you describe the first few hours after the detection?
Who found out about it? How quickly did, you know, word travel?
Was it as fast as the speed of light? Is that how fast the
sound was? And just generally how did the scientific community
individually and as a whole feel about this discovery? And then
I am just opening up and you can go one at a time.
Dr. Gonzalez. Yes, let me tell the story. Actually, it's a
very long story. We had been preparing for discovering
gravitational waves for a long time, so we have computer
programs that produce alerts, and we--and those alerts are
alerts in the control rooms, but we didn't have those alerts
quite ready yet when these came. So they were producing Web
pages where codes--which had very smart codes produced by very
smart people were producing Web pages. And because this event
happened in the middle of the night in the United States, these
Web pages were first seen by our collaborators in Europe
because it was daytime for them. But that's again, the strength
of having a distributed collaboration. So there was an email
flurry saying what is this? Who is injecting this now? So it
took us a while to find out that the detectors were all in fine
state, this was not a test, this was not a dream, it was a real
event.
But then we had a very hard work to vet the signal, to
convince ourselves that this was a signal. And that took months
to vet the signal to make sure that everything was okay, that
all our hundreds of monitoring systems did not produce any
earthquake, any lightening, anything strange that could have
caused this, and then to also analyze this event to get all the
physics and astrophysics out of it, that took months of work by
many hundreds of people.
Dr. Reitze. Yes. We in California are usually the last to
know about anything because we're on the farthest time zone. So
I got to work--I took my daughter to school and I got to work
at 7:30 this morning and I read my emails first. That's my
routine. And I saw a number of emails saying you need to look
at this. This is serious. And the more I looked at it, the more
I went wow. This is actually unbelievable.
And this thing that Gabby pointed out about injections, one
of the things that we do to test ourselves is we inject
signals. We can actually wiggle the mirrors to produce the kind
of signals that I showed you. And we do it sometimes secretly.
So there was--after people saw this signal, they said to
themselves, oh, this must be a blind injection. And there were
only four people in the collaboration and I was one of them
that knew that this was not a blind injection. So I got a lot
of emails saying Dave, can you confirm whether this is an
injection or not? And I would send back, no, this is not an
injection. And at that point, interest ramped up very
dramatically. By the end of that day, I think a number of--you
know, probably the entire collaboration knew we had something
really hot.
Dr. Shoemaker. I'd just add a little bit more. I talked a
little bit about this dream of multi-messenger astronomy where
you could see simultaneously on the ground with radio
telescopes or the FERMI satellite and gravitational waves
coming in all at once. An important necessity for that to work
is that we be able to identify the signal as soon as possible
after it is detected. It was 3 minutes after the waves cross
the Earth that we had a signal that was unambiguous and clear
that said something has happened here that requires attention.
For me, it was, again, when I first woke up 3 hours before
Dave did, I'd been actually working with a close European
colleague in Germany on just this question of whether or not we
could perform injections. And we've been pulling our hair out
because we knew technically we had a problem that we needed to
solve before we could properly do the injections. So he thought
only four people knew, but I knew also. It couldn't be an
injection. We didn't know how to do them at that moment.
It took only minutes to realize that something had changed,
but it's taken months for me really to integrate it into my
vision of things. You work on something for 40 years dreaming
about the day when the detection will come. It takes months for
it to finally sink in.
Dr. Crim. So very quickly, first of all, this gave me an
opportunity to walk into the Director's office and say I have
good news for once. But I want to say something about the
collaboration because, you know, we've watched as this
information propagated through and our program officers learned
about it and all. The way the collaboration handled this is a
model of how you do modern big events in science. The rumors
were circulating but they vetted the signal, they wrote the
paper, they had it reviewed. They had it published in a premier
journal before--they had reviewed in a premier journal before
they had the press conference announcing the result. That's the
classy way to do science.
Mr. Perlmutter. Well, thank you. And I yield back.
Chairman Smith. Thank you, Mr. Perlmutter.
The gentleman from Alabama, Mr. Palmer, is recognized.
Mr. Palmer. Thank you, Mr. Chairman.
Dr. Reitze, in 2014 BICEP2 experiment team announced that
they had found evidence of gravitational waves, but the
observations were later shown to be the result of galactic dust
and were discredited. How confident are you that this or some
other type of error is not responsible for the detection of
gravitational waves in this case?
Dr. Reitze. Yes, that's actually an excellent question and
one that we worried very much about ourselves. I think the
way--first of all, the thing you can say about it is that we
actually had two different detectors. We had the one in
Louisiana and the one in Hanford. They're independent. They're
operated totally independently. They're uncorrelated. They both
saw the same signal. It had the same characteristic in signal.
The data that we analyzed from that actually showed that
the signal was completely consistent. It was found by many
different methods. There were a lot of other checks that were
done because, as was mentioned before, there are other things,
noises that can creep in, so we looked at our detectors and
convinced ourselves that there was nothing that was perturbing
our detectors.
We also did a statistical analysis. Without going into much
detail, we calculate what's the probability that this could
actually be false, and how many--if you had to run for how many
years, would you see an event that looked real, was false? We
couldn't actually put a bound on that number. It's more than 1
in 200,000 years.
That said, we also looked at other things. Could somebody
have done an injection? We talked about injections. Could
somebody have, you know, secretly hacked into our computers and
done this? We checked every path that we could think of and
even some that we couldn't think of after we thought about it a
little bit more and convinced ourselves that, no, that was not
possible either.
The answer to your question is I think we're very
confident. I would say this, too. You know, we expect to see
more of these signals, so we hope that in the next--you know,
the data that we still have sitting--you know, we're analyzing
right now that we'll see more of them. And having more of them
gives you confidence.
Mr. Palmer. I want to give you somewhat of a follow-up on
that, and any of you can answer this, and that's the practical
application of this because, as my colleague Mr. Massie from
Kentucky and I were discussing, GPS doesn't work without
relativity. Do you see any practical application of this? And
I'm not implying that this is not viable for the sake of
science and science--what would any of you see as a practical
application?
Dr. Reitze. Of----
Mr. Palmer. That doesn't mean my time's up.
Dr. Reitze. Yes. Of detecting gravitational waves? It's
hard to see anything in the short-term. Some people, for
example, thought about you might be able to use them for
communication because they go through everything. I mean, your
bodies are being--my body is being bathed by gravitational
waves right now. But it turns out that to generate them you
need big huge black holes, so it's hard to see that.
I think in the short term--and, you know, I feel more
confident talking about the short term--the things that we'll
see that will come out of this research are the technology, you
know, transfers that come from the work that we do to build
these detectors in computing and optics and lasers, servo
controls, vacuum systems, things like that.
Fundamentally, it's hard to see. But again, you know, for
me this is inspiration because it allows us to see the universe
in a way we've never seen before. And for all of us, that's why
we got into science. That's why we like to do it.
Dr. Crim. I really love the GPS mention that you make
because it's certainly the case that when Einstein did general
relativity, he had no idea it was going to help me find a
Starbucks. And there are remarkable things like that in the
future. But as I said before, I wish I could tell you which
one, I think we all do, but they're out there.
Mr. Palmer. I have to credit Mr. Massie with that question.
It helps to sit by a physicist from MIT.
Mr. Massie. Engineer.
Mr. Palmer. Engineer, okay. Dr. Shoemaker, not long after
the announcement on February 11, the Indian Cabinet granted
approval for LIGO-India Project. Can you give us an idea of the
impact of additional observatories coming online?
Dr. Shoemaker. Yes. The really wonderful thing about the
India opportunity is that it's far to the south of all of the
other existing detectors. We have the Hanford, Washington, and
Livingston, Louisiana, detectors. There's the Virgo detector
from Italy, which is in Pisa. There's KAGRA, which is a
Japanese detector. But if you look from a big distance from the
Earth, they're all pretty much in a line. And the wonderful
thing about the India site is that it's to the south of that.
And that gives us a bigger tripod that we can use to look in
the sky and try to localize the source of a gravitational wave,
and it will have a remarkable and unique effect on our ability
to pinpoint in the sky.
Mr. Palmer. Thank you, Mr. Chairman. My time is expired.
Chairman Smith. Thank you, Mr. Palmer.
And the gentlewoman from Massachusetts, Ms. Clark, is
recognized.
Ms. Clark. Thank you, Mr. Chairman and Ranking Member
Beyer. This is truly just a great hearing and we are so excited
about the results. And as you said, Doctor, it just really--
this is inspirational science and sort of fulfills our cravings
as human beings for exploration. But what I find really
impressive is that--and this has been touched on by some of my
colleagues--it's really a decade--decades of partnership and
significant funding, I think 1.1 billion total over many, many
years going from basic research to building LIGO.
And what I want to know because I feel this is such a
success story for us to tell about what it means when you can
talk to your students and say you can begin, you can end, and
you can remain on this project, what that means. How do you put
together a project of this size? How do you keep benchmarks
with it? How do you manage something that goes on for many
different people over such a long period of time and end with
the success that you've had? And I certainly appreciate the
classy rollout. But I think that, you know, I'm very interested
in how you do that because I think some of the technology that
you ended up using you couldn't foresee in the beginning, so if
you could just speak to that.
Dr. Reitze. Let me try and start, and I know David
Shoemaker will also have some, I think, good answers or good
comments about that.
First of all, when you get the project--I mean the idea of
interferometry, you know, goes back to actually the '70s, Rai
Weiss and even some guys in Russia thought about it. And so the
question is what you then have to do to make this work. And so
you write down a list of things that you need to study and
investigate. You start investigating them using, you know,
money from the National Science Foundation, what I would call
individual investigator grants, and then you get to a point
where you realize that that it could work and that there's lots
of work to be done but it's more of an engineering. You know,
you take the ideas that you've tested--you've studied and you
have to engineer them. And then you get into the project phase.
And I think one of the things that LIGO--well, first of
all, LIGO got started--I think it was the first big major
project that NSF had done, and it had a rocky start to it
because, well, you know, it was so big. It was a factor of 100
bigger than anything else had ever done. We'd done prototypes
40 meter that you--we didn't think of everything. And so there
was some management changes that had to take place, but
eventually, we got an organizational--a robust organizational
structure in place that understands project management, the
fact that you have budgets, accounts, and things like that. You
have to track them. You have to make sure--you're given a
finite amount of money. You have to make sure that you build
everything you need to build with that finite amount of money.
You have to understand how everything fits together, system
engineering.
So there are a lot of things that we learned and then
borrowed to make LIGO work. And I think both initial LIGO and
in particular advanced LIGO was quite successful because we
take these things that we learn from project management and we
apply them, too. So it's actually a testament to not only the
scientists but a lot of businesspeople. We had a lot of
accountants and things like that working on doing this. So
there's lots to be proud of here.
Ms. Clark. And was that a different model, sort of having
lots of accountants, or was that just continuation of work
you'd done before----
Dr. Reitze. Well, no, no, no. It was----
Ms. Clark. --being on a different scale?
Dr. Reitze. --a complete--to do big science, you need to
have an infrastructure that not only includes the scientists
and the engineers and the students--we had a lot of students
involved--but you need to have, you know, people that know how
to track projects. You need to have people that know how to,
you know, track budgets and things like that. So that was
something that we figured out once we had to go into the big
science model of it, and we put together a structure that ended
up being successful.
Ms. Clark. Yes.
Dr. Gonzalez. Let me say that the project model has been
very successful in this case due to the very good management it
had, but the human side of this is that, like you were saying,
there are graduate students whose career in this is in
research. It's 4 or five years, not 20.
Ms. Clark. Right.
Dr. Gonzalez. But they are still interested. They were
then. I was one of those graduate students in the beginning
that I knew I wasn't going to be discovering gravitational
waves in my Ph.D. thesis. I did a thesis on something that was
going to help the construction of these projects, the
sensitivity of this detector, and that was exciting enough.
It's inspiring people to be part of something bigger, and that
is what inspires our undergraduate and graduate students to
work for a few years even though some of them have been part of
the detection now. But many are proud of having been part of
this in the past, and we are attracting many more.
Ms. Clark. Wonderful.
Dr. Crim. May I briefly----
Chairman Smith. Yes.
Dr. Crim. --comment?
Chairman Smith. We are--we do have a time factor involved
here----
Dr. Crim. Okay.
Chairman Smith. --but please go on and----
Dr. Crim. I----
Chairman Smith. --respond.
Dr. Crim. Let me just very briefly go from the inspiration
to some of the practicalities of doing this. At the Foundation
we have these remarkable program officers. The collaboration
that we build is through what's called a cooperative agreement,
and the--one of the striking things I've learned that I've been
at the--been at the foundation is how complicated project
management is. And the program officers, working with the
people and the project, it's really a hand-in-glove
relationship. And there's an enormous structure if you're going
to spend $400 million of the taxpayers' money. And we're
careful about it, and it involves these close collaborations.
Chairman Smith. Thank you, Ms. Clark.
Ms. Clark. Thank you.
Chairman Smith. The gentlewoman from Virginia, Mrs.
Comstock.
Mrs. Comstock. Thank you, Mr. Chairman. And I'd like to
thank our witnesses so much. It's so exciting to see your
enthusiasm. And I'm thrilled that we had one of our local high
schools here. I think we still have some of the students here
from Oakton High School in Fairfax, and we appreciate them
being here. And I wanted to ask you, even though we don't have
that time travel thing that we could do, if for each of you if
you could go back to being in high school and you were looking
at this field and you were looking at how someone might get
engaged and involved in this exciting opportunity and career
that you all have had an opportunity to do, what would you tell
them to do today and going forward in their educational
experiences, their volunteer experiences, you know, where they
can get internship opportunities and any Web sites or other
resources that you might provide for the Committee that we
could share with them or that you might direct them to here
today if you could speak to that.
Dr. Shoemaker. Let me just start by saying briefly, this
field didn't exist when I was in high school, but I think what
I found was really crucial was to find something I was
passionate about and just throw myself into it. That was really
the key for me in being able to focus enough on a topic--you
know, I was a young and wild one at one point, and it took
finding something and also finding someone. It wasn't actually
when I was in high school but when I was in the university that
I found Rai Weiss, who has remained my mentor for the--all of
my career, someone who was inspiring to me, somebody who was a
role model, who looked to me like they understood what was
important in what we were trying to do and could--was also good
with a soldering iron. And I think those kinds of things, you
find somebody that really turns you on. It gives you the focus
to actually follow through with things that look really tough
when you start out. Thank you.
Dr. Gonzalez. Let me say that when I was a high school
student I began liking science and physics because I liked
asking questions. So that's what you need to do the most, ask
questions. Don't shy away from questions. There are no dumb
questions.
About material, we do have in our Web site in LIGO.org a
lot of material, and we also have people, emails of people who
you can contact to ask any questions, and we are receiving lots
and lots of questions and we answer them all. And we also have
some material for teachers to use in their science classes.
There are also programs organized by the American Physical
Society for high school like Adopt-a-Physicist so you can ask
teachers to contact LIGO people, collaboration people to act as
a consultant and answer questions.
Mrs. Comstock. So is there like a package we can give to
our high schools that you----
Dr. Gonzalez. There's a K-12----
Mrs. Comstock. --all have?
Dr. Gonzalez. --packet----
Mrs. Comstock. Great.
Dr. Gonzalez. --for students that we have developed, yes.
And there are a lot more material----
Mrs. Comstock. Great.
Dr. Gonzalez. --for teachers and students.
Mrs. Comstock. Right. Thank you.
Dr. Reitze. Just to follow up a little bit, one of the
things that I think is very important more when you get to the
college level but it can happen at a high school level is to go
up to a professor, all right, and ask them is there interesting
research that you're doing that I can get involved with? So all
of us got started actually doing research as college students.
You know, we hadn't even decided what we wanted to do yet. And
even in high school--so at Cal Tech, for example, we have in
the--just in LIGO alone we take in three or four high school
students every year, all right, and we give them, you know, a
pretty well-defined project, and, you know, we mentor them to
make sure that they get through it. They get exposed to, you
know, seminars and things like that.
And I suspect that a lot of universities especially in the
Washington, DC. area there are a huge number of universities. I
would imagine that those kinds of things exist here, too. If
they don't, they're not that hard to set up so----
Dr. Crim. I want to associate myself with the comment about
passion. I think being passionate about science is something
that's driven us all.
As far as this research comment is an important comment,
and the Foundation supports research experiences for
undergraduates to just provide that kind of an opportunity.
There are programs that reach down into the K-12.
I want to make one brief comment, though, about how your
question relates to how we function as a nation. I am a child
of Sputnik. That event and the focus on science directed many,
many people for more than a generation into science. And the
Nation made a huge commitment to our being the global leader in
science. Those kind of moments are the things that will invite
these folks to come in.
Mrs. Comstock. Thank you. I appreciate that passion and for
the students, these are your role models that you are looking
for in the science field. If they look and sound like this,
grab them. Thanks.
Chairman Smith. Thank you, Mrs. Comstock.
The gentlewoman from Oregon, Ms. Bonamici, is recognized.
Ms. Bonamici. Thank you very much, Mr. Chairman.
What an exciting topic and thank you so much for holding
this hearing today so we can learn more about this very
exciting research. And I wanted to align myself with the
comments of Mr. Tonko and others about the value of taking
risks and the value of this sort of persistence and
perseverance over the years and sometimes decades.
I want to take just a moment to acknowledge my alma mater,
the University of Oregon, for their efforts in this discovery.
The university was one of the founding groups of the LIGO
scientific collaboration. And I know that the university
scientist Dr. Robert Scofield participated in testing the
detectors at the site in Livingston, Louisiana, on the day that
the gravitational wave was recorded.
And almost simultaneously, the LIGO's partner site in
Hanford, Washington, where University of Oregon graduate
students were stationed, registered the wave. University of
Oregon is responsible in part for the environmental monitoring
and really investigating that the wave was in fact a
gravitational wave. When anything happens in the Northwest, we
think it's an earthquake, right, so they in fact confirmed that
this was a gravitational wave.
And I know Professor Frey as well, Raymond Frey, who leads
the university's physics department and their team on the LIGO
project--that includes five Ph.D. students, a post-doc, and
three faculty members. So I'm proud of the University of
Oregon. I know that their report really helped the scientists
with their confirmation.
One of the problems with being one of the last Members to
ask a question is that a lot of the topics have already been
touched on. I was actually in an Education hearing with the
acting Education Secretary, so I wanted to ask to--if you could
follow up a little bit. I know the question was asked about how
we could get materials to teachers in classrooms, but I also
was wondering if a researcher who's unaffiliated with the LIGO
collaboration has access to the data.
Dr. Gonzalez. Yes. We have--we--in LIGO.org you can find
the actual data, one hour of data before and after the
detection. And people have already downloaded and----
Ms. Bonamici. Terrific.
Dr. Gonzalez. --are analyzing it. We are going to--we have
made the data from initial LIGO runs. They are also available
and people have been looking at that. And we will make the
formats of data that we have taken available to the public in
the future. So we are very committed to open access and the
public access to the data.
Ms. Bonamici. Terrific. And I really appreciate all the
comments that I've heard all of you make about the importance
of engaging especially students and the internship
opportunities and how do we help students follow their passion?
I know Mr. Loudermilk was talking about the App Challenge. My
office did that as well. I had Adam Barton from Sunset High
School win the App Challenge. He also happens to be a very
talented pianist, which is confirming my theory that
integrating the arts into STEM results in more creative,
innovative people.
Do any of you have any sort of new approaches to bringing,
you know, first generation students, for example, and students
from underrepresented groups into the STEM fields?
Dr. Gonzalez. Yes. We are very committed to increasing the
diversity not just in our collaboration but in general in the
scientific community. We have been working very closely with
the National Society of Hispanic Physicists and Black
Physicists for including--for affiliating students and teachers
from colleges with large underrepresented----
Ms. Bonamici. Excellent----
Dr. Gonzalez. --minorities. We work with several of those
universities like Southern University, University of Texas, Rio
Grande Valley. Thank you for that work. It's important to get
them interested and also to retain them by having positions and
having good working environments.
And then finally, I know it's been touched on this morning,
but could you expand a little bit on the importance of
international collaboration? I know that there was a lot going
into this, but we also talk about this when we talk about, you
know, space research. You know, we have jurisdiction over NASA,
for example. Can you talk about the importance of the
international collaboration with LIGO and this discovery?
Dr. Gonzalez. Yes. We are very proud of having had very
international effort on this. It's been led by the United
States. The United States has been a leader in this effort both
within the scientific--the LIGO scientific collaboration, which
is an international collaboration. We have been living this in
the United States but also living--uniting all the other
collaborations, getting agreements with all the other
collaborations so that we don't compete with each other but we
collaborate for better science. We collaborate in forming a
network.
And that has been very important and very efficient, too,
because we have recruited many students and scientists from
other countries to help us here in the United States, for
example.
Ms. Bonamici. That's a great model for collaboration. And I
see my time is expired. I yield back. Thank you again, Mr.
Chairman.
Chairman Smith. Thank you, Ms. Bonamici.
That was very deftly done to include the University of
Oregon to the extent that you did.
Ms. Bonamici. It is my alma mater.
Chairman Smith. Totally understandable.
Thank you all for being here today. This was really a
special and even unusual hearing just because there was so much
to learn and so much excitement about a new discovery. It's
also nice, I think, from our point of view just to see how much
mutual support there is among you all, how much collaboration,
even camaraderie perhaps. So I appreciate that. We had a full
house when we began today. They've trickled out over time, but
it was nice to start off with every seat in the room occupied
and a tribute to what you all have done. So thank you all very
much.
Dr. Gonzalez. Thank you all for holding this hearing.
Dr. Crim. Thank you, Mr. Chairman.
[Whereupon, at 12:05 p.m., the Committee was adjourned.]
Appendix I
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Answers to Post-Hearing Questions
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