Remember that "earthlike" in this instance doesn't refer to a similar weather system, but mass and probably composition. Most planets this close to stars discovered so-far have been called "hot Jupiters" because they seem to be gas giants. Any planet with a 14-day orbit around a typical yellow or red dwarf star would definitely not have oceans of liquid water. "Venus-like" would be a better term; If there is a substantial atmosphere it would almost certainly have to resemble that of Venus, thus it would be highly convective. The entire planet would be brutally hot, regardless of which side is facing the sun. And the hotter the atmosphere, the more it expands away from the planet's surface. The further from the surface, the faster it is lost. Some kind of volcanic replenishment might need to be invoked to maintain it, given the close orbit. Or high surface gravity. An "earthlike" planet could still have 4, 5, 6-gee surface gravity or more- and thus be a terrible place for us to visit. If the atmosphere is Marslike, thin and tenuous, then I'd agree with you that the dark side would be cold. We're talking about a planet like Mercury in that case- only closer to the sun. Otherwise, I'll stick with a Venus. I think the earth pretty darn special. We are going to have to look long and hard before we find one with temperatures and other physical conditions similar to what we have here. You're such an optimist, Kim! (that's a good quality!) On 5/23/07, Kim <kimharch@cut.net> wrote:
Assuming an earth-like planet, with oceans and similar weather processes, I think even then the dark side would be very cold. With an atmosphere to moderate the weather, it likely wouldn't experience the extremes of the Moon or Mercury, but relative to our (human) needs for comfort, I still think the dark hemisphere would be cold. Consider how on earth a relatively small change in incoming radiation causes very large temperature swings. (Oh-oh, an oblique reference to global warming - unintended, I promise.) I know some science fiction writers have postulated that life on a planet that is tidally-locked with its parent star would likely inhabit a very narrow "ring" in the twilight zone between the fully-illuminated hemisphere (too hot) and the fully-dark hemisphere (too cold). Would be an interesting place to visit.