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Question about early Earth
Was the Moon in a close Earth orbit essential in preventing a runaway greenhouse effect like we see on Venus. The Earth was much more volcanically active in it's youth and would have put out much more CO2 and other greenhouse gases. Did the Moon siphon off much of the Earth's atmosphere in earlier times.
I'm trying to figure what sort of planets we'll be looking for in the future that will be possible candidates for life outside our solar system. Obviously the gas giants we've found in close orbit around other stars couldn't support life. Would being in the right orbit around the right sized star be enough to create the conditions for terrestrial type life, or is a double planet like our Earth-Moon neccessary? Last edited by blue.planet : February 7th 06 at 12:30 AM. |
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Question about early Earth
blue.planet wrote: Did the Moon siphon off much of the Earth's atmosphere in earlier times. No. Earth's gravity is substantially stronger than the moon's, so the moon couldn't pull away atmosphere. IIRC, oceans are pretty good about sucking up excess CO2. Would being in the right orbit around the right sized star be enough to creat the conditions for terrestrial type life, or is a double planet like our Earth-Moon neccessary? I don't think it's necessary, but it can help. At a minimum, a large moon helps by minimizing random flips in a planet's tilt, which can have drastic effects on the environment. Mike Miller |
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Question about early Earth
blue.planet wrote: Was the Moon in a close Earth orbit essential in preventing a runaway greenhouse effect like we see on Venus. The Earth was much more volcanically active in it's youth and would have put out much more CO2 and other greenhouse gases. Did the Moon siphon off much of the Earth's atmosphere in earlier times. I'm trying to figure what sort of planets will be looking for in the future that will be possible candidates for life outside our solar system. Obviously the gas giants we've found in close orbit around other stars couldn't support life. Would being in the right orbit around the right sized star be enough to creat the conditions for terrestrial type life, or is a double planet like our Earth-Moon neccessary? -- blue.planet blue.planet, there exists an "ecosphere" or "goldilocks" region around every star where a planet can have liquid water... Venus is just inside this region so it never cooled down enough for liquid water to exist... water is much more erflective than land surface.. so this might be another important reason for the earth to cool down. On venus all wate exists in the form of water vapour.. and water vapour IS a greenhouse gas.. So it would aid in heating up the planet and not cooling it down. By the way, your hypothesis of the moon siphoning off gas from the Earth is unlikely. Sure, the moon was a lot closer to the Earth but it served to increase tidal force on Earth and also volcanic activity(for eg Io, Jupiter's moon has volcanic activity attributed to massive tidal forces from Jupiter). So a closer moon would aid volcanic activity and not stop it...as for your other question, a double planet may be a necessity as studies have shown that the moon helps stabilize the Earth's orbit and reduce wobbling about its axis and moderate the seasons. However until we find another planet with life bearing conditions WITHOUT a large satellite it remains to be proved...... Gautham Ram. you can contact me at Looking forward to hear from you.. |
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Question about early Earth
blue.planet wrote: Was the Moon in a close Earth orbit essential in preventing a runaway greenhouse effect like we see on Venus. The Earth was much more volcanically active in it's youth and would have put out much more CO2 and other greenhouse gases. Did the Moon siphon off much of the Earth's atmosphere in earlier times. In the 60s it was speculated that the Moon is the reason the Earth's atmosphere isn't like that of Venus. The idea was that, even though its gravity is so much less than Earth's, it would perturb enough molecules to escape velocity over time that the amount of atmosphere would be depleted. Larry Niven picked up on that and incorporated it into at least two stories. It was never a widely held hypothesis, and since it was first proposed better modeling indicates that Venus' fate was sealed simply by its proximity to the Sun. I once asked about that here years ago, and Henry Spencer said that a lot of science speculation that Niven used in his stories came from Tommy Gold, an iconoclastic astronomer who was part of the steady state universe crowd (with Fred Hoyle) and also is known for having gotten in a row with NASA during Apollo. All of this is from memory and possibly way inaccurate. |
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Question about early Earth
If you read the original work on this issue, you find it applies
very well to the Earth in the solar system, and not at all outside the solar system. Oh, good, that'll be handy for some sci-fi projects I'm working on. Less need for every habitable planet to have big moons. Do you have a link to the original work? Mike Miller |
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It's interesting to read that the moon actually stabilizes the Earth and makes it more habitable. Also that liquid water may have played an important role in reflecting solar radiation to keep the world cool. Thanks. |
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Question about early Earth
"Maury Markowitz" wrote in message ... wrote: No, pretty good actually. Gold was the guy that got onto TV by claiming the moon probes would sink in the miles-thick dust on the moon. OF COURSE it's miles thick, its been there practically forever and there's no mechanism to solidify it back into rock like there is here. In Gold's defense, he does from time to time come up with an idea that's right. Stopped clock and all that. It would be a mistake to dismiss him as a complete crackpot. And he did help build a camera specifically for Apollo (basically for close up shots of the Lunar dust.) So they built the landers and tested. Nope, no problem. But Gold wouldn't stop even when confronted by direct counterexample. The TV robots eventually gave up listening to him -- something that no longer happens unfortunately. He still turns up, unnamed, in various creationist books. Why? Because the lack of thick dust on the moon means it can't be very old, right? Maury |
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