Originally Posted by mhgaffney
If you've been following this thread -- you will recall that a few posts back W*gs denied vociferously that he ever claimed that Vulcanism over nearly all of the Venusian planet was caused by a runaway greenhouse effect.
Now he states (above) that it is. Obviously he doesn't have a clue what he's talking about.
For the record -- there is no chance that a greenhouse phenomenon can heat up the core of a planet -- and cause vulcanism like what exists on Venus. No chance.
At least 60% of the sunlight reaching Venus is reflected away by the dense cloud cover -- so only 40% of the sunlight is available for the greenhouse effect.
Wow. You are truly ****ing clueless.
The reason the surface of Venus is hot is due to a runaway greenhouse effect. That temperature is still far below the temperature required to create active vulcanism.
The surface of Venus is also volcanic in nature - as opposed to Earth's surface, which is a combination of volcanic, metamorphic, and sedimentary rock. That's because there is no liquid water on the surface of Venus. Likewise, there doesn't appear to be any plate tectonics on Venus - the heat generated by radioactive processes seems to continue to heat Venus' mantle until the crust disintegrates and the entire surface subducts and overturns, basically. Quite a different process than what occurs here on Earth.
BTW, the Venusian surface is ~300-600 million years old and there could be current volcanic activity.
For more information regarding the runaway greenhouse on Venus, read this article.
It will get you started.