CAPE CANAVERAL, Fla. (AP) -- The fastest-swiveling
space science observatory ever built rocketed into orbit Saturday to scan the
universe for violent celestial explosions that astronomers believe represent the
birth screams of black holes.
NASA launched the observatory -- named Swift for its
speedy pivoting and pointing -- following weeks of delays caused by hurricanes
and a three-day postponement due to rocket trouble. The unmanned rocket climbed
smoothly through a cloud-flecked midday sky, and delighted flight controllers
wished the spacecraft a successful mission.
Swift, a $250 million collaboration by NASA, Italy
and Britain, should begin its hunt for gamma ray bursts by January and erase
some of the mystery surrounding these explosions and black holes.
Gamma ray bursts are the most powerful events in the
universe, exceeded only by the cosmic curtain-raising Big Bang itself. Lasting
just a few seconds on average, the bursts appear out of nowhere like flashlight
beams and are thought to signal the formation of black holes. Astronomers
theorize the collapse or collision of massive stars is what produces black holes
-- so dense not even light can escape -- and that the resulting gravitational
energy sends gamma rays shooting out across time and space.
"We think that, perhaps, bursts are the birth cries
of black holes and we're seeing these throughout the universe," said NASA's Neil
Gehrels, principal scientist.
A single gamma ray burst releases more energy than
the sun will emit in its entire lifetime at all wavelengths, Gehrels
said.
Put another mind-blowing way, "If you added together
everything in the rest of the universe during that second, it would not be as
bright as the gamma ray burst," said Pennsylvania State University
astrophysicist John Nousek, director of mission operations.
So far, astronomers have managed to identify only a
couple dozen gamma ray bursts, as close as a few million light years and as far
as 12 billion light years. Swift should zero in on two gamma ray bursts a week
as far away as 15 billion light years, representing the very first generation of
stars, for a grand total of more than 200 during the planned two-year
mission.
The spacecraft will scan one-sixth of the sky at any
one time and thus see one-sixth of all gamma ray bursts out there. The
observations will help scientists learn more about what the bursts are and how
many are out there, and how and when black holes form.
As soon as Swift's gamma ray burst-alert instrument
spots an explosion, the spacecraft will quickly turn all by itself so that two
other on-board telescopes can observe the X rays and ultraviolet and optical
light streaming from the afterglow.
This swinging into position will take just a minute,
lightning speed by astronomical standards because of Swift's six momentum
wheels, double the usual number for a science satellite. Speed is crucial
because once the ever-so-brief gamma ray burst subsides, the afterglow is
difficult to find and fades within hours or sometimes weeks.
News of the gamma ray burst and its precise location
instantly will be relayed to astronomers everywhere by the mission control
center at Penn State. Ground observatories can then be aimed to assist in the
afterglow analysis.
Deputy project manager Tim Gehringer calls Swift "the
roadrunner of spacecraft, speeding from birth to birth as it advances mankind's
knowledge of the most violent explosions in the universe."
Scientists are quick to point out that military spy
satellites may well exceed Swift's swiftness. On the scientific front, though,
this rapid-response observatory has no peer.
Until now, 15 minutes was considered "really fast"
for a space observatory and its team to respond to a late-breaking astronomical
event, said Anne Kinney, director of NASA's universe division. Swift "is a
completely different level of fastness, one minute, one minute and designed to
do that consistently, not dependent on anybody answering their cell phone," she
said.
The Hubble Space Telescope, by contrast, takes hours
if not an entire day or two to swivel into an impromptu viewing
position.
After chasing gamma ray bursts for a year or two,
Swift will expand its repertoire to other rapidly occurring cosmic
events.
"If you want to see something like that," Nousek
said, snapping his fingers, "who you going to call? Swift is the people to
call."