Mercury - a left-over of the crash that created the Moon?, Highly speculative but maybe worth it |
Mercury - a left-over of the crash that created the Moon?, Highly speculative but maybe worth it |
Dec 7 2007, 12:19 PM
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Member Group: Members Posts: 147 Joined: 14-April 06 From: Berlin Member No.: 744 |
Having agreed upon the Moon being created by a grazing collision with a Mars-sized object, could we give any thoughts to what happened to the impactor afterwards? Since it was a grazing collision, it might have been melted but not destroyed, only with some material ripped from it (and from the Earth) which ended up in Earth orbit to coalsce into what we know as the Moon today. But what happened to the impactor after it passed the Earth? Could it still hang around somewhere in the Solar System? I suppose it would bear some significant markings after the event, for instance have its outer layers stripped. But wait a second... Mercury DOES have its outer layers stripped off, with an unusually high mean density resulting from a core which could be considered oversized for such a small planetary body. In the wake of MESSENGER beginning to reveal Mercury's secrets in January, could anyone bother to give any thoughts to this idea? I am not sure whether it had been put forth previously or not, I am just curious if it could make any sense to have the impactor impact the Earth in a grazing manner and then end up parked in an elliptical orbit close to the Sun, with its outer layers stripped and an "oversized" original core left inside...
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Dec 8 2007, 06:46 AM
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Member Group: Members Posts: 258 Joined: 22-December 06 Member No.: 1503 |
Could Mercury have been created from a planetary collision with Earth? No. It is not possible. Mercury is too far down the gravity well for that to be possible.
I once thought that maybe a collsion with Venus created Mercury, explaining both Mercury as a core and Venus with a very slow retrograde rotation. I don't know how this is possible either. There would need to be a massive body closer to the Sun for this to be possible. There isn't any. But Mercury crashed into something. Perhaps there was once a planet closer to the Sun but has since disappeared for whatever reason. Maybe there once was a Hot Jupiter too close to the Sun and it eventually evaporated? Highly unlikely. More likely, there were once many planetary objects closer to the Sun and most got either thrown into the Sun or out into the far reaches of the solar system very early in the Solar System's history. The interactions would be far too complex to figure out. More objects would also mean that there would more likely be collisions. So you get the Earth-Moon system, the Venus Retrograde rotation, and the stripped down core of Mercury all from different collisions early in the solar system's history. Where did these object go? Some of them became part of the remaining planets. Others thrown out would be difficult to identify as such even if we were able to find them. But then we have the recent evidence that suggests that these huge collisions are fairly rare. It's been calculated that they may only occur in 1 out of 20 star systems. So something is not correct. Perhaps Mercury is not a stripped down core of a planet that it appears to be. But that is difficult to believe too. Confused? I am. |
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