Exploring the Universe

30 April 2005 Physics Today Online April 2005
Exploring the Universe Roger Blandford
http://www.physicstoday.org/vol-58/iss-4/p10.html#bio

In mid-February, I participated in a NASA Science Update press
briefing that presented gamma-ray and radio observations of a flaring
neutron star. A neutron star is a solar-mass worth of mundane and
exotic nuclei and fundamental particles trapped by gravity at
supranuclear densities, exhibiting superfluidity and superconductivity.
The star is encased within a solid crust, a liquid ocean, a gaseous
atmosphere, and a relativistic plasma magnetosphere capable of inducing
zettavolt electromotive forces and radiating intense, coherent
emission. Neutron stars are used to test general relativity and to
search for gravitational radiation. The neutron star in question is
also a "magnetar," which gives it one further remarkable feature. The
magnetic field strength is around a petagauss, a billion times larger
than can be sustained on Earth and well over the quantum electrodynamic
critical field. A magnetar is a star designed by a committee of
physicists, each trying to outdo the other. On this occasion, it
appears that a stellar flare occurred, released 13 orders of magnitude
more magnetic energy than the greatest solar flare, and created a burst
of gamma rays intense enough to reach across the galaxy and rattle our
atmosphere.

The public reaction to this announcement, naturally, emphasized the
apocalyptic. Of course, we have statistically larger threats to worry
about, but the magnetar explosion does serve as a dramatic reminder
that the human race is living in rented accommodations. By contrast,
the astrophysicist's response is to try to explain the details (and
modesty plus lack of space preclude my telling you the true
explanation). However, there is a third response that is germane at
this time. The discovery of a magnetar explosion, for all its
impressive credentials, is actually commonplace. It exemplifies the
strange new worlds we usually find every time we develop a new
observing capability. No one has called astrophysics "normal science"
recently.

Vision for Space Exploration
In January 2004, President Bush announced his Vision for Space
Exploration, in which he committed the nation to exploring the "solar
system and beyond," returning humans to the Moon before 2020, and
ultimately sending them to "Mars and beyond." NASA then began a radical
transformation directed towards achieving the president's ambitious
goals. At the same time, and somewhat ironically, the funding for the
wildly successful Explorer program was halved. It was Swift, the latest
Explorer, that produced the most detailed observations of the exploding
magnetar just one month after launch.

Most astronomers and physicists have reacted to the president's
announcement and NASA's response with suspicion. I do not think their
response is because of hostility to the manned space program. Although
some of us embrace it enthusiastically, others have a position similar
to mine on football. I do not care much for football, but most
Americans, including the rest of my family, do. So when the Superbowl
comes around, I am happy for them and do not storm around the house
trying to turn off the TV. We astronomers and physicists fear that the
Vision for Space Exploration is being implemented too hastily, with a
daunting schedule, whose technical realism has not been validated, and
whose likely total cost is not being addressed. I recall the
admonishment of Richard Feynman in a similar context: "For a successful
technology, reality must take precedence over public relations, for
nature cannot be fooled." The manned space program does not seem to be
following the "go as you pay" strategy advocated in 1990 by the
Augustine Commission and echoed by subsequent National Research Council
studies. Instead, there appears to be a headlong rush to commit
precious resources in a manner that could lead to disappointment and
waste.

In addition, we worry about the impact of the president's vision on US
space science missions. These take a long while, sometimes decades, to
complete. The careers of some of the most capable and creative
engineers and scientists in the US are invested in space science.
Accordingly, there is a careful and painful process--involving
comprehensive and inclusive decadal surveys--that transforms a wish
list, whose execution would exhaust the gross national product of the
Milky Way into a prioritized, realizable, and updatable program, which
NASA, to its credit, has largely adopted. The process is not perfect,
but it works, and the results are there for all to see.

Now the fine print of the vision and subsequent implementing
documents, together with the president's 2006 budget, leaves room for a
robust space science program. However, NASA is taking on an expanding
portfolio of new responsibilities with large and unknown costs. The
Moon-Mars program has top priority, and its integrated cost, not yet
estimated, has been guessed to be many hundred billion dollars. The
immediate bill for returning the space shuttle to flight has been far
greater than anticipated. The long-term commitment to the International
Space Station, whose purpose has not yet been clearly articulated, is
as strong as ever despite NASA's estimated pricetag, including the
shuttle, of a further $44 billion. In addition, the far-sighted
Prometheus nuclear reactor program, which was to have supplied the
propulsion for the Jupiter Icy Moons Orbiter, has had its liver pecked
out by the federal eagle. JIMO has been put on hold in the current
budget, three months after a $400 million contract was awarded.
However, like its namesake, Prometheus will live on as a very expensive
program. To put it bluntly, the overall NASA budget is hardly likely to
grow in the present climate, and so, given the huge commitments, space
scientists fear serious triage in future budgets.

The Hubble Space Telescope dilemma illustrates the impending crisis
perfectly. Astronomers were expecting the space shuttle to mount a
fourth servicing mission to keep the HST operating and to install a new
camera and a spectrograph, to allow it to continue its remarkable
program of discovery, for an advertised cost of roughly $350 million.
Following the Columbia tragedy, NASA Administrator Sean O'Keefe decided
to cancel the mission on safety grounds. It was then proposed to
service the HST robotically, and a $150 million contract was awarded. A
month later, that option was terminated on the grounds that the final
cost would be much greater than $350 million and too high to justify.
The future of the HST will likely be decided in the political arena,
and astronomers nervously wait to learn its fate.

I think there is another element to our reaction to the vision, and
this is where magnetars come in. Astronomers are proud of what they
have collectively accomplished, and they are suffering from wounded
pride. In recent years, a standard model of a flat, accelerating,
underweight universe has been established that has thrown theoretical
physics into turmoil. The discovery of extrasolar planets, 150 and
counting, demonstrates that our solar system is unrepresentative with
immediate consequences for the quest for extraterrestrial life. Black
holes of all sizes have been found in abundance and seem to power many
of the most dramatic cosmic phenomena we observe.

Going beyond astronomy, the impressive evidence for water
from the Martian rovers, the daily solar weather reports that enable us
to predict the
"particlefall" on Earth, and the breathtaking images from Cassini-
Huygens show NASA at its can-do best. The remarkable success rate of
NASA's space science missions is a miracle to anyone who has been
involved in one in the months prior to a launch! Just as on any opening
night--although with launches there are no successive nights--all that
hard work and experience, the collaboration between scientists and
engineers, and that between NASA, universities, and industry, really do
come together.

These enduring space science discoveries have both used and stimulated
other disciplines--physics, of course, but now also planetary science,
engineering, chemistry, biology, and computer science. Even more
important, space scientists have embraced their responsibility to
engage and inform the public, especially schoolchildren. We have an
easy job. Sit next to someone on a plane. If you want to talk to them,
tell them you are an astronomer; if you don't, try rocket scientist!
The public appears to understand that we are all truly fortunate to
live in one of the great epochs of discovery and takes a vicarious
interest in what we are doing. I assert that the great success of space
astronomy has carried NASA through some rough times.

Future program
The planned astronomy projects (and the prospects in other areas of
space science are as exciting) include:

The James Webb Space Telescope will observe the youngest and most
distant galaxies in the infrared and show us how they really formed.
The Space Interferometry Mission will observe stars with
microarcsecond positional accuracy so as to find new planets.
The Constellation-X Observatory will observe gas just before it
crosses a black hole event horizon and test general relativity.
The Laser Interferometer Space Antenna will open up the gravitational
radiation spectrum and also test general relativity by observing the
merging of distant black holes.

The Joint Dark Energy Mission is designed to study the details of the
universe's acceleration.
The Inflation Probe should measure the polarized microwave radiation
that, it is conjectured, comes from the epoch of inflation.
The Black Hole Finder Probe will transform very hard x-ray astronomy,
largely ignored for 30 years, and enable astronomers to see into the
heart of gas-enshrouded quasars.
The Terrestrial Planet Finder will seek oxygen- and water-bearing
Earth-like planets around nearby stars.

These are all wonderful projects, but they are very expensive, and
priorities will have to be set. Many astronomers are concerned that
future choices will be based less on the proven criteria of scientific
timeliness, technical readiness, and fiscal credibility and more on
resonance with a narrow interpretation of the president's vision. In
particular, they worry that programs with a connection to life will be
favored over fundamental investigations in the inanimate, physical
sciences. The uncertainty is taking its toll on the talented younger
scientists and university students who have started working on these
projects. They do not understand why their voyages of exploration are
being interrupted and some of the ships recalled to port.

What is to be done?
First we have to adapt, not because we have somehow failed, but
because the rules have been changed and there is no going back. We have
to make the case anew for space science, using a different vocabulary.
We have to explain why all science is exploration, whereas not all
exploration is science. In particular, we must not allow science--the
systematic and fundamental understanding of the world around us--to be
redefined. We should be careful not to disparage the larger part of the
vision, which may be unconcerned with science but which is a valid
activity for NASA to undertake if it has a popular mandate to do so. We
must now explain why NASA's contributions to astrophysics and cosmology
will "improve life here" and are as interesting and important as the
wish "to extend life to there" and "to find life beyond," to quote the
new NASA vision statement.

We must also exercise our democratic rights, contact members of
Congress (and, indeed, buttonhole anyone we meet), and not be reticent
about explaining the issues and asking for what we think is best.
Congress is getting plenty of help from other sources! Perhaps no
community is more important in this regard than our physics students.
After all, the vision is so ambitious that they will be in the middle
of their careers before it is completed! Those students will provide
the core of the technically sophisticated workforce needed in the
future. Are they inspired by the opportunities in space science the
same way that my generation was aroused by the response to Sputnik? How
important is it to them to understand dark energy, how galaxies are
born, what happens around black holes, what other planetary systems
look like, and so on? If it is important, then maybe they will send an
e-mail to their representatives and senators expressing their views.

The coming year will be pivotal for NASA. On paper, its commitment to
space science is as strong as ever, but it is taking on some formidable
challenges that will put pressure on its ability to continue with its
broadly based science program. Moreover, NASA will need to sustain
public interest and political support over the coming decade, and
wonderful discoveries like the magnetar explosion should surely help. I
hope that NASA's leadership will continue to engage the astronomy and
physics communities in planning how best to explore the universe.

Roger Blandford is the director of the Kavli Institute for Particle
Astrophysics and Cosmology at Stanford University.

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