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Author Topic: South Pole-Aitken basin- The Biggest Crater in the Solar System !!  (Read 5166 times)

Offline neilep

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How could something as massive as the South Pole-Aitken basin on the moon have been created without smashing the Moon into little pieces ?



Considering how small the moon is...and the fact that this impact crater at 2500 kilometers  in diameter....(The largest Impact crater known in the Solar System)how could the moon still be here ?...



 

Offline ukmicky

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I think because it only takes a small comet or asteroid travelling at high speed to create such a crator.
 

another_someone

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Also, if it was a comet (rather than an asteroid), it will mostly be water ice, and pretty well shatter itself to bits before shattering the moon.
 

Offline neilep

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THANK YOU BOTH (Michael & George)

I suppose I assumed/presumed it was a big big thing that impacted (with lots of mass)!!....after all...it IS a massive crater..
 

Offline Ophiolite

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Neilp, despite the observations by ukmicky and another someone, you may rest assured that this was a very large impactor. Notice, however, in your illustration, that the basin has subsequently been peppered by many more smaller impactors. That demonstrates that the big impact was old, occuring early in the moon's history. Very likely that was early during the heavy impact phase that ended about 3.9 billion years ago. At this time the inner solar system was a dangerous place, with unsettled orbits and many planetesimals still whirling around, left over from the original accretion event.

Edited for abominable typographical errors. [:-[]
« Last Edit: 22/10/2007 09:41:53 by Ophiolite »
 

Offline neilep

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Neilp, despite the observations by ukmicky and another someone, you may rest assured that this was a very large impactor. Notice, however, in your illustration, that the basin has subsequently been peppered by many more smaller impactors. That demonstrates that the big impact was old, poccuring early in the moon's history. Very likely that was early during the heavy impact phase that ended baout 3.9 billion years ago. At this time the inner solar system was a dangerous place, with unsettled orbits and many planetesimals still whirling around, left over from the original accretion event.

THANK YOU Ophiolite

Your explanation is wonderful and clarifys a lot up.......That must have been one big trauma !!
 

Offline JimBob

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Yes it had to be a large scale impact - the kinetic energy needed for that is larger than any (known) event on earth.
 

Offline Karen W.

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Thats scary does one think it might happen again... and if it did would there be any chance it would remain in tack or would another shot like that just be minimally damaging?
 

Offline Ophiolite

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Thats scary does one think it might happen again... and if it did would there be any chance it would remain in tack or would another shot like that just be minimally damaging?
Time permitting I shall try to figure out a plausible size for the impactor. It would certainly be bigger than anything that is currently in an Earth crossing orbit. I'm not even sure if Ceres, the largest of the asteroids would be big enough to make it were it diverted from its orbit by some event or other. At any rate it would require a highly improbable visitation by a wandering minor planet, that somehow managed to avoid Jupiter, made it to the inner solar system and then hit the moon. So just about no chance at all.
However for the sake of discussion, if it did happen you could expect a similar sized crater and a bunch of large material thrown into orbit some of which could land on Earth with devastating effect.

Quote from: JimBob
Yes it had to be a large scale impact - the kinetic energy needed for that is larger than any (known) event on earth.
Although it is smaller than the impact of a Mars sized object that is believed to have led to the formation of the moon in the first place.

 

lyner

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Impacts of 'dead' objects like the Moor survive much longer than on 'live' bodies like Earth.  Apart from the effects of erosion, which destroys small craters, the long term effect of Continental drift could have healed up a lot of big impact craters (?) subduction and all that.
 

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