Originally posted by twhitehead
So how does that work? Does this mean it radiates less on its night side? Or is the "highest albedo" thing 'total reflection' rather than 'total radiation' during day time? ie the heat radiation is ignored.

For one thing, Venus is closer to the sun and gets about twice the irradiation of light so high heat is much more probably all by itself. Not quite twice, but still it gets about 2400 watts per square meter compared to Earth which clocks in at 1355 watts per square meter. So even before the massive greenhouse gas effect took place on Venus it was hotter than Earth.

Originally posted by sonhouse
For one thing, Venus is closer to the sun and gets about twice the irradiation of light so high heat is much more probably all by itself. Not quite twice, but still it gets about 2400 watts per square meter compared to Earth which clocks in at 1355 watts per square meter. So even before the massive greenhouse gas effect took place on Venus it was hotter than Earth.

The solar constant for Venus is about 2620 W/m^2, so it is practically twice that of Earth.

Originally posted by Soothfast
The solar constant for Venus is about 2620 W/m^2, so it is practically twice that of Earth.

I didn't look it up, I just did a quick back of the envelope calc, so I was close, about 10% off. Venus started out with a worse deck of cards than Earth. In fact, early Earth had to rely on greenhouse warming to keep from freezing because the early sun was weaker than now. It has been gradually getting hotter over millions of years. I wonder what Venus received in watts per meter squared a couple of billion years ago. Must have been less than today. Wonder if Venus could have been a water world early on?