Even though I have seen all of the episodes of this series I usually stop what I am doing to watch one when the Science Channel runs one. One of the things I like about them is Paul Gasek's narration.

Now it is widely accepted that a Mars size object collided with the earth about 4 billion years ago from which the moon was formed, but they never mention the fate of the rest of the material.

Now that Mercury has been observed up close and personal they know that it suffered a major calamity a long time ago too. So, is it even remotely possible that Mercury was the object that struck earth and left behind the rubble that became the moon? Or has anyone even thought to look into the possibility?

OK, somebody shoot down my speculation.

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Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.

The moon is the material from Earth leaving behind the Pacific Ocean basin. We may have been a water planet prior to that event.

... Or has anyone even thought to look into the possibility?

OK, somebody shoot down my speculation.

Yes greatly... :-) (By many researches with more details than me.)

The most likely scenario is that the earth and moon were formed from collecting all the combined material. The moon's density suggests that the moon collected a lot of the earth's outer crust. Whatever collided will have been smashed to then be swept up by the earth and moon.

Above a certain mass, I guess you get the type of collisions where nothing big can escape. Everything smashes and the re-coalesces.


Keep searchin',
Martin

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See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)

OK, so the mass of the earth and moon is the same, plus or minus, as the mass of the pre collision earth and whatever hit it. I have read that the object that collided with the earth was approximately the same mass as Mars so the earth picked up a lot of additional mass as the result of the collision.

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Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.

OK, so the mass of the earth and moon is the same, plus or minus, as the mass of the pre collision earth and whatever hit it. I have read that the object that collided with the earth was approximately the same mass as Mars so the earth picked up a lot of additional mass as the result of the collision.

From what I remember of that show was that earth was hit a glancing blow. If it had hit head on earth would no longer exist. So something must have been left of that Mars size object. How does Mercury size up now to mars?

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[/quote]

Old James

OK, so the mass of the earth and moon is the same, plus or minus, as the mass of the pre collision earth and whatever hit it. I have read that the object that collided with the earth was approximately the same mass as Mars so the earth picked up a lot of additional mass as the result of the collision.

From what I remember of that show was that earth was hit a glancing blow. If it had hit head on earth would no longer exist. So something must have been left of that Mars size object. How does Mercury size up now to mars?

This kind of the direction my thoughts have lead. Nobody has ever claimed that the entire mass of the striking object was absorbed into the earth-moon system which leads to several possible outcomes if it wasn't. Most likely scenario is that whatever escaped the earth's gravity was slung out of the solar system entirely but it does seem possible that the densest part of the object recoalesced and took it's own orbit inside Venus and is now Mercury thus explaning why Mercury is much denser than Mars or the moon.

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Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.

... but it does seem possible that the densest part of the object recoalesced and took it's own orbit inside Venus and is now Mercury thus explaning why Mercury is much denser than Mars or the moon.

The higher density of Mercury is fully explained by the distance of its orbit from the sun. Just as is the abundance of water for the earth and the lower densities for the gas giants Jupiter, Saturn and Neptune, all for each for their respective orbits.

I don't know of any suggestions that Mercury might be a captured object. Its orbit is far too 'normal'.


Keep searchin',
Martin

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See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)