March 30, 2015
Comet Crash Producing Answers, Further Questions
More than a week after the Deep Impact probe smashed into Comet 9P/Tempel 1 on July 4, 2006, scientists are starting to get beneath the surface.
The 23,000-mile-an-hour impact released the energy of nearly 5 tons of TNT. It blasted a crater in the comet's surface and kicked up a huge column of debris and "comet dust."
Material, in fact, is still coming out, brightening the comet's image in telescopes. NASA's Swift satellite was picking up increasingly strong X-ray emissions several days after the impact, and Earth-based telescopes were registering brightening cometary images, as well. It's been estimated that perhaps 50,000 tons of material have been ejected by the probe's strike.
Meanwhile, the size of the debris cloud has been complicating the task of those trying to analyze the crater. Scientists were sifting through something like 5,000 images of the impact and aftermath in an attempt to determine crater size. One estimate has placed the diameter between 100 and 300 meters, which was on the large end of pre-impact excavation estimates.
Data analysis so far seems to show that the Deep Impact probe hit at a 25-degree angle and penetrated to some depth before its force was dissipated. This would indicate the comet is made of quite porous material and is not simply a chunk of ice. Much of the ejected material, in fact, is very fine stuff having a consistency, perhaps, very much like that of talcum powder.
Spectral analysis has so far indicated the presence of carbon atoms and nitrogen compounds in the ejected material, along with smaller amounts of water, carbon dioxide and ammonia. Hence the jury is still out on whether comets could have "seeded" Earth with the water and organic compounds that gave rise to life.
Stay tuned for further developments. More will be posted as it's released.