A recently discovered rogue asteroid is now headed towards a possible impact on Mars this Jan. 30. While the probability of a collision is a 1 in 75 chance, astronomers are still getting ready to observe the eventif it happens. According to NASA news sources, the impact would occur on Jan. 30 at 10:55 UT (5:55 a.m. in Vermont). Designated 2007 WD5, the asteroid is a very recent discovery. The object was spotted Nov. 20 by a NASA-funded sky survey using a big telescope on Mt. Lemmon in Arizona. The object passed within 7.5 million km (5 million miles) of Earth Nov. 1 on its way to a close encounter (or impact!) with Mars. Astronomers said the asteroid to be about 50 meters (160 feet) in diameterthats big enough to create a large crater. While Asteroid 2007 WD5 will approach Mars from the planets brightly illuminated dayside, it makes it more difficult for spacecraft now orbiting the Red Planet to observe it int he glare of our Sun. However, the Hubble Space telescope might be employed to view the aftermath of an impact if it happens. Huge dust clouds created by the impact would be visible for days or even weeks. Images of Mars taken by Hubble during the late 1990s showed an incredible amount of surface detail, certainly unlike Earth-based telescopes, so the space telescope might be useful to astronomers wanting to catch a glimpse of the event as it happens. If the asteroid is indeed on a collision course with Mars, it would impact at 13.5 kilometers (8.4 miles) per second. The ensuing explosion would be the equivalent of a three-megaton hydrogen bomb. One NASA researcher calculated that the crater formed by such an impact would be nearly a kilometer (0.6 mile) across. This crater may appear to be a pretty big ditch, but when compared to most craters on Mars and the Moon, it would be tiny. However, an impact even of this low magnitude should not be trivialized; such an impact would be a disaster on Earth. Both here and on Mars a lot of rock and dusty debris would be catapulted high into the atmosphere. If an impact occurs on Mars this Jan. 30, it wont be the first time such an event was observed from Earth. Do you remember back in July 1994 when 21 fragments of Comet Shoemaker-Levy 9 slammed into Jupiter? That extraterrestrial event was covered live on television around the world; it was the first time humans ever observed a confirmed comet impactanywhere! It should be mentioned that the 1994 Shoemaker-Levy impacts were calculated a little more than a year before the event. The current possible Mars impactor was only discovered two months ago. Given a 1-in-75 chance of a possible impact, there is at least some small room to anticipate another extraterrestrial-impact spectacular. Whats in the Sky: Two comets should be visible in the sky above Vermont this weekComet Holmes is in Perseus; its dim but big more than 1 across. Greenish colored Comet 8P/Tuttle is now moving between Pisces into Cetus. Its smaller than Comet Holmes at magnitude 6.0 but still visible. Use binoculars to view each comet. Make sure your eyes are dark adapted at least 20 minutes before looking for these faint objects.