origins of comets

[geomouse]

I'm not what anyone would call a character from Big Bang Theory. I do like to ponder the universe though I had, what I thought was, an intersting proposal. Considering the origin of water on earth is generally accepted to be derived from cometary collisions with our fair planet, Earth absorbing and melting the ice, would it be fair to speculate that all the ice and water that make up cometary particles originated here on earth? Could the comets we enjoy today have possibly been knocked out into their respective oblong orbits by one or a series of massive collisions during the formation of our moon? Perhaps our earth was once a much larger, colder snowball a little further from the sun

thanks in advance for considering the possibilities! Really enjoy this site...one of my favourites!

[Chris Peterson]

I'm not what anyone would call a character from Big Bang Theory. I do like to ponder the universe though :ssmile: I had, what I thought was, an intersting proposal. Considering the origin of water on earth is generally accepted to be derived from cometary collisions with our fair planet, Earth absorbing and melting the ice, would it be fair to speculate that all the ice and water that make up cometary particles originated here on earth? Could the comets we enjoy today have possibly been knocked out into their respective oblong orbits by one or a series of massive collisions during the formation of our moon? Perhaps our earth was once a much larger, colder snowball a little further from the sun :?:

No. Everything points to icy bodies forming early in the evolution of the Solar System. The collision that created the Moon wouldn't explain the current positions of icy bodies, nor their composition- which is not just water ice, but CO₂, CO, CN, CH₄, and plenty of other volatiles that would not have been present in large quantities on the Earth 4+ billion years ago.

[bystander]

No. Everything points to icy bodies forming early in the evolution of the Solar System. The collision that created the Moon wouldn't explain the current positions of icy bodies, nor their composition- which is not just water ice, but CO₂, CO, CN, CH₄, and plenty of other volatiles that would not have been present in large quantities on the Earth 4+ billion years ago.

This theory is supported by recent findings in TW Hydrae. http://asterisk.apod.com/viewtopic.php?t=29149

[geomouse]

Thanks for your replies...