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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."
We'd be talking about it for decades. It might actually wake up some people to the NEA threat to our own planet. It might have a devastating and instant effect on the atmosphere of Mars.. which could actually make the planet a little warmer and a little more hospitable.
How we know is more important than what we know.
Even if it misses it should still be a little interesting. If it comes that close, its orbit will be greatly affected, observing the results should be useful?
If the asteroid does hit the impact site would probably make for a good rover mission. Fresh samples of long buried rock without the extra hassle of having to dig it up!
Murphey's fighting Occam, and we're in the stands.
The received wisdom used to be that the meteorite, that caused the disaster in Tunguska, exploded above the surface of the earth. It entered the atmosphere at a relatively shallow angle and heated up much more than it would have if it had come straight down. The result was that a long relatively narrow area of forest was knocked down and there was no impact crater.
On Mars, the atmosphere is much less dense than that of the earth. The meteor in question is large. If it hits Mars, it will reach the surface, it won't vaporize in the atmosphere. The result will be much more like other impacts on the earth that did leave craters. In that light, the comparison with Tunguska doesn't make much sense. I don't know where Steve Chesley got his information on the size of the rock that exploded over Siberia but I bet it wasn't 160 feet across. Something that size would make it to the Earth's surface.
I'll bet they are. Because we have this nice dense atmosphere to sustain our breathing, we tend to forget that mars has only 2 or 3% of the surface air pressure to heat and absorb energy from an incoming rock like we have. The damage will be from a direct surface hit at the rocks full speed and should be visible if it hits on our side of mars, and it will no doubt toss up a few megatons of ejecta, which due to the speed of the wind, will take a while to settle. That does have the possibility of finishing off the rovers. There is a slim chance some of the ejecta may even make it to earth and be found on the antarctic snow eventually, giving us a few more samples of our neighbor to study.
:)
If it hits where we can see it, it should be quite a show and I hope they have a good number of our telescopes, even Hubble, recording like crazy.
I guess we'll find out January 30th. But if its on the far side, we may have to do before and after photo comparisons to find the crater once the dust has settled, and that won't be near as informative as a near side hit would be.
Humm, recently the chinese were accused of doctoring a moon photo. Makes me wonder if the moved crater might in fact be a new one?
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