September 26th, 2011, 12:14 PM
At the orbit of Venus, Earth which is only slightly larger, would most likely have suffered the same fate as Venus for a couple reasons. 1) planets formed that close to the sun had fewer volatiles available, hence less water available to remove Co2 from the atmosphere as happened on Earth, 2) Greater solar irradiation; which both accelerated removal of the lower amount of volatiles and high enough atmospheric temperatures to create a run-away green house by boiling off the young ocean. I've never seen any models about the gravitational locking of Venus' effect on its early atmosphere, though it wouldn't surprise me if researchers like James Kasting and others haven't done that work.
Of course that doesn't mean the Earth couldn't be closer to the sun and still be recognizable as "earth like." The sun wasn't quite a bright in it's early history and it's quite conceivable that an Earth like planet, or one even one larger, could have developed an Nitrogen-based atmosphere with a water-based hydrosphere closer to the sun.
Earth's geology and atmosphere are also very influenced by life--as to those conditions on another hypothetical earth it's still anyone's guess.
Last edited by Lynx_Fox; September 26th, 2011 at 12:30 PM.
Meteorologist/Naturalist & Retired Soldier
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