David, consider that the length of a Venusian day is 243 earth days (retrograde rotation). A Venusian year is about 224 earth days. The day is longer than the year! Venus essentially keeps the same face toward the sun for very long stretches of time; long enough to draw an analogy with a true tidally-locked planet. Yet the thick convecting atmosphere is very efficient at transferring heat uniformily around the planet. The entire planet is hot, regardless of whether it faces the sun or is in darkness. "Hot Jupiter" exoplanets experience the same effect, though they may have no solid surface. On 5/23/07, baxman2@comcast.net <baxman2@comcast.net> wrote:
I was thinking that only one side of the planet could be seen, in much the same way we only see one side of the Moon. The Moon only shows one side to us; but all points on the Moon have both a day and a night, relative to the Sun. If the planet only shows one side to its sun, I agree, only that side would have daylight. The circulating atmosphere is an interesting question.