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NASA's
Historic Deep Impact Mission Reveals Secrets Of Comets |
Posted:
07.11.05
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The journey of the Deep Impact space probe ended with a historic
bang on the Fourth of July when it collided with a comet.
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Nearly 1 billion viewers logged on to NASA's Deep Impact Web
 site
to witness the space probe crash into the Tempel 1 comet at 23,000
miles per hour, sending a cloud of trapped gas and debris into
the atmosphere.
Led by a team of scientists from the University of Maryland,
the mission was the first to capture close-up images of a comet
and its composition.
The pictures contain clues to the formation and evolution of
the sun and planets 4.5 billion years ago.
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Mission specifics |
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Launched on Jan. 12 from Cape Canaveral, Fla., the spacecraft
made a six-month, 268 million mile journey to Tempel 1.
The Deep Impact spacecraft had two parts -- a flyby craft equipped
with high resolution imaging instruments and an 820-pound copper
"impactor" to strike and leave a crater on the comet.
Twenty-four hours before the July 4 collision, the impactor was
released into the comet's path. It captured and transmitted real-time
images of the comet from as close as 18 miles, three seconds before
impact.
On impact, Tempel 1 gave off light six times brighter than expected
before expelling an unexpectedly large cloud of gas and ice, which
blocked scientists' view into the comet's crater.
Scientists estimate the crater is larger than a house and possibly
the size of a football field.
Mission members must wait for the cosmic dust to settle, allowing
a clear view into the comet's interior.
 The
flyby craft was able to transmit real-time photos of the crash.
The Hubble Space Telescope also captured a series of dramatic
photos.
Though not visible to the naked eye, sky gazers in the western
United States and Latin America were able to witness the impact
with a telescope. More than 10,000 people gathered at Hawaii's
Waikiki Beach to watch the impact on a giant movie screen.
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Mission hailed
as a success |
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Mission members at NASA's Jet Propulsion Laboratory in California
exchanged hugs and applauded the mission's success.
"We can say that it went better than we planned. It is absolutely
phenomenal how well it went. We didn't have to exercise any of
our contingency options and the science we're getting back is
phenomenal," mission project manager Rick Grammier told the
NewsHour.
 Initial
analysis of collision images by mission scientists indicates that
the comet, shaped like a pocked, lumpy potato, has a soft, powdery
surface beneath which lies ice and trapped gas.
Other researchers argue, however, that the spike in ultraviolet
light points to a solid surface.
In the coming months scientists will continue to gather and analyze
mission data for clues about the comet's surface and interior
ingredients.
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Comets and
our solar system |
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Comet Tempel 1 was discovered by Ernst Tempel in 1867 and orbits
the sun every 5.5 years. The comet's size is about 8.7 miles by
2.5 miles or half the size of Manhattan.
Composed of ice, dust and gas, comets are thought to be the leftover
ingredients of our solar system.
 "Comets
are the leftover bits and pieces from the outer solar system formation
process. So if we wish to understand the initial conditions from
which the outer solar system formed, the chemical mix and the
structure of the particles that came together to form Jupiter,
Saturn, Uranus and Neptune, then we'd like to study comets because
they haven't changed a great deal in the intervening four and
a half billion years," mission scientist Donald Yeomans told
the NewsHour.
"We're all made of cometary stuff. The carbon-based molecules
in the water that make up our persons are all brought to the early
Earth via comets."
Deep Impact's success paves the way for other missions.
The European Space Agency is planning the Rosetta Mission - which
will land on a comet and scratch its surface -- for the year 2014.
--
Compiled by Monica Villavicencio for NewsHour Extra
Photographs from NASA
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Yes it's true that he came to the United States illegally, but ever since that he has only done positive things. He has a job, pays taxes, does volunteer work, raised a family, and so many other things.
