Venus Radar Request, From Earth Options

[Decepticon]

I'm looking for earth based radar mapping of Venus.

I've had a hard time finding much. I clearly remember seeing images in books as a child.

Any help would be great!

[edstrick]

The only fly in this pudding is that there is a weird near-synchronicity between the rotation period of Venus and the position of inferior conjunctions with Earth. Very-Very nearly the same hemisphere of Venus faces Earth each conjunction! It's not quite exact, but it is improbably close. They've tried to see if the small tidal pull of Earth on Venus at inferior conjuction was more than vanishingly small and might explain this cooincidence, but it seems to be unlikely. The best idea I've heard so far is that the gods must be crazy.

[helvick]

The best idea I've heard so far is that the gods must be crazy.

And are the same crazy Gods responsible for the very slow rotation of Venus? Or is there a plausible\likely explanation for it just happening that way?

[Guest_AlexBlackwell_*]

And are the same crazy Gods responsible for the very slow rotation of Venus? Or is there a plausible\likely explanation for it just happening that way?

Correia and Laskar have published some interesting work on this.

[JRehling]

Correia and Laskar have published some interesting work on this.

I've tried about six of those links, and they are all dead.

I've tried about six of those links, and they are all dead.

However, a summary/abstract appears here:
http://physicsweb.org/articles/news/05/6/6

The low inclination and extremely low angular momentum always made impact-based explanations unlikely. It's pretty hard to smash things together and get things to balance out that neatly. C&L's work seems to conclude that from first principles, that with an atmosphere that thick, the planet's rotation is going to be driven by the atmosphere. Presumably (what the abstract/summary doesn't say), the huge thermal input from the Sun is another part of the story. Saturn, Uranus, and Neptune have bigger atmospheres, but they don't have daysides lit by a Sun measuring a full degree in the sky -- they have two+ orders of magnitude less solar input.

I don't know if anyone has ever looked at this angle, but with Grinspoon, et al, proposing that Venus may have lacked those bright clouds for much of its history, it may have formerly had particulalry large thermal tides if it had an albedo as low as, say, Mars or Earth's continents. If you imagine an atmosphere sticking out tens of km (?) farther on the dayside than the nightside, that's a lot of friction working against rotation.