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Chance for a Tunguska Sized Impact on Mars
Multiple users have written to tell us of an LA Times report that an asteroid may hit Mars on January 30th. The asteroid is roughly 160 feet across, and JPL-based researchers say that it will have a 1-in-75 chance of striking Mars. Those odds are very high for this type of event, and scientists are hoping to witness an impact of a similar scope to the Tunguska disaster. From the LA Times:
"Because scientists have never observed an asteroid impact -- the closest thing being the 1994 collision of comet Shoemaker-Levy with Jupiter -- such a collision on Mars would produce a 'scientific bonanza,' Chesley said."
It doesn't actually say it will be occluded for 2 weeks behind the Moon, it just says that it is currently occluded and it will be 2 weeks until they can calculate it's course. I assume the need to watch where it's going to predict it accurately.
Earth has a much thicker atmosphere.
How we know is more important than what we know.
Did you miss the part where the atmosphere of Earth and Mars are completely freakin' different?
How we know is more important than what we know.
The nuclear winter is a concept that works only on Earth due to our unique atmosphere which lets a bit of sunlight in and prevents a bit of that from radiating out, thus warming our planet. If our atmosphere grew a bit more dusty, we'd reflect more sunlight and become colder.
You cannot apply this concept to Mars, which has no greenhouse effect in the first place. Its surface reflects most of the sunlight already, so reflective dust in its thin atmosphere would make no difference. You also can't apply it to Venus, which is a greenhouse. Its atmosphere is already highly reflective, and it is only as hot as it is because the tiny amount of sunlight it absorbs is prevented from escaping.
This isn't a big impactor. It won't cause any serious global effects, on Mars, Venus or Earth.
Orbit viewer for 2007 WD5: http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2007%20WD5;orb=1;cov=0;log=0#orb
Loos like the asteroid could come close to Earth's orbit in 2011. Hope it hits Mars before that!
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Kinda neat that this coincides with some new findings about Tunguska and how it may have been far smaller than was earlier predicted. More or less the atmosphere may worked to direct the blast, and the explosion may have been significantly smaller. Of course this effect would be far less significant on Mars with its thin atmosphere.
It may be far greater impact than Tunguska was, but only cause may suck more at math than we though.
http://www.sandia.gov/news/resources/releases/2007/asteroid.html
Working for one of the companies that were involved in the Beagle 2, what is believed now is that the Beagle 2 made an orthogonal impact against the wall of a meteorite crater. The airbags and the rest of the landing system were designed to cope with a nice impact at an angle against flat ground. In the end it just flew straight into a wall.
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It's currently a 24th magnitude object which means it's extremely faint and can only be viewed from earth by very large scopes on dark nights. The moon's illumination makes observation that much harder.
The Nasa neo page for this object has more info about the asteroid.
Not really.
its = possessive
it's = it is
"Ayn Rand is a bloody socialist compared to me." - Robert A. Heinlein
The greenhouse effect isn't the point at all, here. In the nuclear winter scenario, you've merely reflected more sunlight (or kept it from the ground, at any rate). No greenhouse effect is required, only an atmosphere that isn't *so* thick that high deck of clouds or dust are irrelevant. (You're correct, this *is* the case at Venus.) Not only is Mars susceptible to this same effect, it was the global Martian dust storm in 1971 (which caused surface cooling on that planet) that led Sagan, Pollock, and Toon to apply the principles to Earth in the first place.
Also, Mars's albedo is 0.15, significantly lower than Earth's. I'm not sure what you mean by "Its surface reflects most of the sunlight already," but I have a hard time seeing Mars's surface as being very reflective.