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Githyanki
2014-Feb-28, 01:33 AM
It's reasonable to assume that conditions on early-Venus were very similar to conditions on early-Earth; a thick primordial atmosphere and liquid water as was the case on both Mars and Earth; now, if there was water on Venus, as to the evidence of granite, which only forms in liquid water, then the surface was below 100C and not the 400C it is today; there had to have been a convection within Venus similar to Earth and Mars and the start of early plate-tectonics. My question is, is there evidence of this on the surface? Are there rift-valleys, orogenies or other signs of the start of plate-tectonics like on Mars?

NEOWatcher
2014-Feb-28, 01:05 PM
My question is, is there evidence of this on the surface?
According to Wiki (http://en.wikipedia.org/wiki/Geology_of_Venus#Global_resurfacing_event), it seems not.


Are there rift-valleys, orogenies or other signs of the start of plate-tectonics like on Mars?
I found an interesting NASA site with various maps and images of Venus (http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-venus.html).

grapes
2014-Feb-28, 01:51 PM
now, if there was water on Venus, as to the evidence of granite, which only forms in liquid water, then the surface was below 100C and not the 400C it is today;
Granite does not form in liquid water at the surface.

swampyankee
2014-Mar-01, 12:10 AM
Venus is much more difficult to investigate than Mars. Indeed, it's probably more difficult to investigate than Titan; at least the surface environment on Titan doesn't require new technology for the electronics to function (cold is good for digital circuitry), even though the required delta V is greater for a Titan mission than a Venus mission.

Aristarchusinexile
2014-Mar-01, 12:24 AM
Seems to me that all this water on these early inner planets supports my idea that many planets began as balls of water in which minerals grew from the centre, finally breaking surface as a huge landmass, then the landmass breaking apart. Venus can't be that difficult to explore, as the Russian landers sent back photos from the first attempt, way back in the stone ages of interplanetary travel. Interesting also that extraterrestial life could first be found in Venusian clouds. http://news.discovery.com/space/alien-life-exoplanets/are-venus-clouds-a-haven-for-life-130516.htm

CJSF
2014-Mar-01, 04:38 AM
"All this water" isn't really that much by volume compared to the size of the planets. Are you suggesting the Earth began as a 12000km diameter ball of water?

CJSF

tusenfem
2014-Mar-01, 02:44 PM
Seems to me that all this water on these early inner planets supports my idea that many planets began as balls of water in which minerals grew from the centre, finally breaking surface as a huge landmass, then the landmass breaking apart. Venus can't be that difficult to explore, as the Russian landers sent back photos from the first attempt, way back in the stone ages of interplanetary travel. Interesting also that extraterrestial life could first be found in Venusian clouds. http://news.discovery.com/space/alien-life-exoplanets/are-venus-clouds-a-haven-for-life-130516.htm


Off topic and ATM.
infraction

Githyanki
2014-Mar-07, 10:11 PM
The fact that Venus my spontaneously spout off lava and resurface itself does put a wrench in trying to figure out if it had plate-tectonics. That and the 400C heat and thick, poisonous, acidic atmosphere really gets in the way of studying it.



"All this water" isn't really that much by volume compared to the size of the planets. Are you suggesting the Earth began as a 12000km diameter ball of water?

CJSF

Earth is a desert-world compared to some of the other planets; it's suspected that something came along and removed most of the water; Mars, for it's size, has more water, per ratio than Earth does. It is my untested theory that given Venus' thick-atmosphere, it had lots of water; perhaps it was a green ball like Earth when it formed (don't quote me on this).

Noclevername
2014-Mar-11, 01:31 AM
It is my untested theory that given Venus' thick-atmosphere, it had lots of water; perhaps it was a green ball like Earth when it formed (don't quote me on this).

The "Wet Greenhouse" theory is fairly widely accepted: http://en.wikipedia.org/wiki/Runaway_greenhouse_effect#Venus