Oct. 27, 2010: This month, Comet Hartley 2 has put on a good show for backyard astronomers. The comet's vivid green atmosphere and auburn tail of dust look great through small telescopes, and NASA's Deep Impact/EPOXI probe is about to return even more dramatic pictures when it flies past the comet's nucleus on Nov. 4th.
Hartleyids (amateur image, 200 px)
Comet 103P/hartley 2 photographed on Oct. 20th by Mike Broussard of Maurice, Louisiana. [larger image]
Another kind of show might be in the offing as well. Could this comet produce a meteor shower?
"Probably not," says Bill Cooke of NASA's Meteoroid Environment Office, "but the other night we saw something that makes me wonder."
On Oct 16th, a pair of NASA all-sky cameras caught an unusual fireball streaking across the night sky over Alabama and Georgia. It was bright, slow, and--here's what made it unusual--strangely similar to a fireball that passed over eastern Canada less than five hours earlier. The Canadian fireball was recorded by another set of all-sky cameras operated by the University of Western Ontario (UWO). Because the fireballs were recorded by multiple cameras, it was possible to triangulate their positions and backtrack their orbits before they hit Earth. This led to a remarkable conclusion:
"The orbits of the two fireballs were very similar," Cooke says. "It's as if they came from a common parent."
There's a candidate only 11 million miles away: Small but active Comet Hartley 2 is making one of the closest approaches to Earth of any comet in centuries. It turns out that the orbits of the two fireballs were not only similar to one another, but also roughly similar to the orbit of the comet. Moreover, meteoroids from Comet Hartley would be expected to hit Earth's atmosphere at a relatively slow speed--just like the two fireballs did.
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link to science.nasa.gov]
The more we observe with our science the more we may come to think that magic and sorcery are just a better explanation.
New Zealand