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Swift Observatory Makes
Penn State the Center of the Universe
Traveling sports teams sometimes complain that Penn
State is “in
the middle of nowhere.” But to astronomers worldwide, Penn
State is in the center of the universe, now that NASA’s newest
space observatory, named “Swift,” has been launched
into orbit. That’s because Penn State will control the satellite
and receive the information it collects about gamma-rays bursts.
If
a gamma-ray burst were to explode near Earth, it would blast away
the ozone layer, causing radiation damage, runaway global warming,
and mass extinctions of humans and other species. In a few seconds
or less, a gamma-ray burst spurts out more energy than the Sun
produces in its entire lifetime. The most powerful and mysterious
explosions ever observed in the history of the universe, second
only to the theorized “Big Bang,” gamma-ray
bursts were first discovered during the 1960s by spy satellites
seeking to spot violations of the nuclear-test-ban treaty on Earth.
Surprised by the discovery of such powerful explosions in space,
authorities at first classified the bursts as “top secret,” but
now they are one of the hottest research topics in astrophysics.
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John Nousek |
“The
underlying nature and cause of gamma-ray bursts have been among
the leading mysteries of astrophysics for the past 30 years,” says
John Nousek, professor of astronomy
and astrophysics at Penn State.
Nousek is director of mission operations for NASA's
Swift Gamma-Ray Burst Observatory, which on November 20th blasted away from Cape
Canaveral into Earth orbit, where it is expected to detect new gamma-ray
bursts every other day or so.
Five years ago, when Swift was only
the dream of a team of scientists, NASA selected Penn State to
play three important roles: lead the building of two of Swift's
three telescopes and control the Swift satellite from a Mission
Operations Center near University Park. NASA selected Swift to
be funded over about thirty competing proposals for other types
of space observatories, according to Neil
Gehrels, at NASA's
Goddard Space Flight Center, who now is Swift's principal investigator.
Swift's lead partners include scientific institutions in the
United States, the United Kingdom, and Italy.
Now that Swift is
in orbit around the Earth, the Penn State control center is the
bulls-eye target for the steady stream of new knowledge that
Swift is expected to beam down to Earth for the next two to eight
years.
Swift earned its name by being built to “swiftly” swing
into position, faster than any space telescope of its kind, to
provide clues about lightning-quick gamma-ray flashes by capturing
the quickly fading “afterglow” signals that linger
for a while in X-ray, visible, and ultraviolet wavelengths. Unlike
other telescopes, which take hours or days to maneuver, Swift is
designed to automatically point at a gamma-ray burst within one
minute after its very-wide-angle gamma-ray telescope detects a
burst. Then, within the next minute, its X-ray and ultraviolet/optical
telescopes more precisely position the burst in order to capture
its afterglow signature and gauge its chemical composition and
distance from Earth.
Because the intensely bright gamma-ray bursts
are like beacons shining through everything in their paths, they
can reveal clues about the gas between and within galaxies along
the line of sight from Earth. “We hope to learn about events
we suspect of causing gamma-ray bursts, including the moment of
death of a massive star and the simultaneous formation of a black
hole,” Nousek
says. “We also hope to use gamma-ray bursts to learn what
the very early universe was like, to study how black holes form
and how stars die, and to get some idea of how the distribution
of gamma-ray bursts in the universe affects possibilities for the
evolution of life on other planets.”
Penn State team members
at the Mission Operations Center have their work cut out for them
during the next month or two. They will be working in shifts 24
hours a day, seven days a week, while they bring Swift's systems
up to full operation so it can provide new data to eager scientists
around the world. The team expects each of Swift's three telescopes
to achieve the milestone of “first
light” within the next few weeks. David
Morris, a second-year
graduate student who helped to program and calibrate one of Swift's
telescopes, comments, “Swift is a tremendous mission for
a graduate student's career because we expect to be doing really
new science at a really fast pace really soon.”
Many
Penn State people contribute to the Swift program under Nousek's
leadership, including undergraduate and graduate students, postdoctoral
researchers, faculty, staff, engineers, and technicians. Faculty
in the Penn State Department of Astronomy and Astrophysics who
lead important subsystems include Dave Burrows, leader of the international
team that designed, built, and will operate the Swift telescope
that detects X-rays; Peter Roming, leader of the international
team that designed, built, and will operate the Swift telescope
that detects ultraviolet and optical radiation; and Margaret
Chester,
leader of the Penn State Mission Operations Center. Thomas
Taylor,
of the Applied Research Laboratory, is leader for Penn State project
management; Lisa Brown, of the College
of Earth and Mineral Sciences,
is leader for Penn State public outreach; and Peter
Mészáros,
of the Department of Astronomy
and Astrophysics and the Department
of Physics, is leader for the overall science team for the Swift
mission.
“A gamma-ray burst is not very likely to damage Earth's
atmosphere in our lifetime, although astronomers have shown that
a gamma-ray burst could have caused one of Earth's early mass-extinction
events,” says
Mészáros, Distinguished Professor of Astronomy and
Astrophysics and a leading gamma-ray-burst theorist. “We
can expect a gamma-ray burst to happen only once every million
years in our galaxy, but one would have to happen close to Earth—roughly
in the spiral arm where our planet is located—to do much
damage here. Of every 300 gamma-ray bursts that occur in our galaxy,
only one is likely to be close enough to damage us, so that means
we have one chance every 300 million years of being harmed by a
gamma-ray burst.”
Barbara K. Kennedy
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