Calvin Set to View Deep Impact

June 15, 2005 == MEDIA ADVISORY

Blasting a hole in a comet with an earth-launched spacecraft sounds like the
stuff of science fiction. Or fare for a Hollywood blockbuster.

But this example of American space ingenuity is real and will be displayed,
appropriately enough, on July 4.

That's when NASA's Deep Impact spacecraft will hurl a probe onto the surface
of a comet named Tempel 1 in an effort NASA hopes will crack the comet's
surface and expose, for the first time, the interior of a comet.

That probe is about the size of a table, albeit a table that weights 820
pounds! When it hits the comet's nucleus at some 23,000 miles per hour it is
expected to cause a crater close to 700 feet wide and 200 feet deep.

In a press release NASA noted that: "The crater produced by the impact could
range in size from a large house up to a football stadium, and from two to 14
stories deep. Ice and dust debris will be ejected from the crater, revealing
the material beneath. The flyby spacecraft has approximately 13 minutes to take
images and spectra of the collision and its result before it must endure a
potential blizzard of particles from the nucleus of the comet."
 
The moment of impact, scheduled for approximately 1:52 am eastern time on July
4 will complete a journey of 173 days and 431 million kilometers or 268 million
miles for the Deep Impact spacecraft.

Calvin College's astronomy professors Larry Molnar and Deborah Haarsma are
fascinated by the project and planning observations from the school's
observatories. In fact Haarsma is opening up the Observatory to the public on
both July 3 and July 4 for anyone who wants to watch the crash.

Calvin first will host special Observatory hours on July 3 for a last view of
the pre-impact comet. Observing that day will begin at 10:30 pm, one hour
after sunset.

Says Molnar: "The comet will be about 10th magnitude, appearing as a faint,
fuzzy blob in the eyepieces of our telescopes. It will be visible from Grand
Rapids until about 1 am, when it will be lost in the glare of the horizon. We
will then switch to live images from our New Mexico robotic telescope, which
will be able to track it for a full hour past the time of impact before the
comet sets in New Mexico as well."

Then on the night of July 4, Calvin will offer the first direct view of the
post-impact comet.

Says Haarsma: "We will be open from 10:30 to midnight, so following your
local fireworks display, you will have the chance to see the full fireworks
ignited by the collision. The ejected material will have had time to spread
out and shine its brightest, so we should expect to see rich features through
the telescope and may even be able to pick it up through binoculars."

Molnar and Haarsma are hopeful that the skies over West Michigan will be clear
that night. If the skies in West Michigan are not clear Haarsma will use the
school's robotic telescope in New Mexico to feed data from there directly to
the Grand Rapids observatory, still allowing people to view the impact.

It will be a unique experience the two professors say.

"The probe should penetrate the solid crust of the comet," Molnar says,
"creating a crater the size of a football field. As the gas and dust released
from the impact spreads out, the comet may increase in brightness some ten to a
hundred times as seen from Earth. Indeed, the impact may be enough to split
the fragile object into two or more major fragments."

Molnar notes that prolonged exposure to the harsh conditions of space forms a
crust on a comet analogous to that on a baked Alaska. Deep Impact will
therefore allow a unique study of the pristine material of the comet interior.

The Calvin Observatory website is updated with info and links about the
project, including a finding chart indicating where to find the comet that
night.

See http://www.calvin.edu/observatory/deepimpact.html
For more information about Deep Impact see http://www.nasa.gov/deepimpact

Contact Deborah Haarsma at 616-526-6340 or Larry Molnar at 526-6341

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Received on Wed Jun 15 13:00:27 2005