Calvin News

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 Calvin Observatory to the public on July 4 for anyone who wants to see 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."

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.