A European spacecraft that has been peering through the thick, roiling clouds of Venus for the past three years has found further evidence that the inhospitable planet once had oceans, volcanoes, and a system of plate tectonics similar to those at work on Earth. The Venus Express has mapped the planet’s southern hemisphere using infrared imaging, and found heat variations in the surface rocks, which allows researchers to speculate on the chemical composition of those rocks. Different surfaces radiate different amounts of heat at infrared wavelengths due to a material characteristic known as emissivity, which varies in different materials [SPACE.com].
In certain highland areas, researchers detected cooler patches of rock whose thermal signatures resemble those of granites on Earth. On our own planet, granites are made during the process of rock recycling that goes on at the edges of the great geologic plates that cover the Earth. At the boundaries of these plates, ancient rock is pulled deep into the planet, reworked with water and then re-surfaced at volcanoes. Critically, then, if there is granite on Venus, there must also have been an ocean and a process of plate movement in the past [BBC News].
In the study, to be published in the Journal of Geophysical Research, researchers found the granite-like rocks only in certain areas of the Phoebe and Alpha Regio plateaus. Explains study coauthor Joern Helbert: “It’s not all highlands that are different; it’s mainly very young volcanic areas that look different.” … This contrasts with basaltic rocks – characteristic of oceanic basins – seen by the Russian landers of the 1970s and 1980s which touched down away from the highlands. [BBC News]. The new findings support the theory that the plateaus of Venus were once continents produced by ancient volcanoes and surrounded by oceans.
Researchers say that the only way to determine the chemical composition of the rocks with absolute accuracy would be to send a lander down to sample the surface of those plateau regions. Study coauthor Nils Müller says it’s also possible that such a mission could detect small Venusian volcanoes that are still active. “Venus is a big planet, being heated by radioactive elements in its interior. It should have as much volcanic activity as Earth,” he said [SPACE.com].
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Image: ESA – AOES Medialab
July 14th, 2009 at 7:44 pm
I WONDER WHAT WOULD HAPPEN TO VENUS OF A LARGE SOLAR ARRAY SHADED THE ENTIRE PLANET FROM THE SUN AND DROPPED ITS TEMPERATURE DOWN TO SOMETHING MORE EARTHLIKE?
July 14th, 2009 at 11:35 pm
This is when the Star Trek crew would fire photon torpedoes that would evenly disburse chemicals that would produce a cascading, multi-layered reaction that free oxygen and such and negate the greenhouse effect…
;-)
As for blocking the sun, I s’pose if you positioned your disc properly between the planet and the sun, you could cause an eclipse. If you got close enough to the sun where a small disc would block a large area at the planet’s orbit, it’d be doable.
I’d be interested in looking at a comprehensive estimate of what chemical reaction would occur naturally in the atmosphere with a temperature drop.
July 15th, 2009 at 6:41 am
The next step after the solar array/mirrors/aerosols are in place to block the sun and cool Venus would be to seed it with oxygen producing microbes and simple plants. Of course this would be done after the temperature was below 100 degrees Celcius. But then we can have two planets worth of resources to exploit! YAY!
July 15th, 2009 at 8:52 am
You will need to speed up the spin, any poor bugger who ended up living there would have one hell of a long work week.
July 15th, 2009 at 1:46 pm
Rather than shading it with a disk, what if you enlarged its orbit? Moved the planet further from the sun. Likewise, what if we could bring Mars in a little closer?
July 15th, 2009 at 7:48 pm
#3: You’d still need a way to permanently lock the CO2 out of the atmosphere. Just seeding microbes wouldn’t be enough. They might fix CO2, but when they die and decay, the CO2 goes right back into the air. You have to add some mechanism that permanently buries organic matter deep into the crust.
#4: One idea would be to take a big, icy comet and crash it into Venus at the appropriate angle to restart the spin. This might have the added benefit of blowing away much of the greenhouse atmosphere, and give Venus a chance to “reboot” its atmospheric evolution at a stage before the runaway greenhouse effect got established (And add some water to the mix). Any if you’re really ambitious and envisioning truly supreme technological levels, then you could use Mercury or maybe even Mars as the impactor, to give Venus a large moon and re-kickstart plate tectonics.
#5: Earth would probably get in the way. . . . The Earth-Sun and Venus-Sun Lagrange points, I think, are already disrupted by the other planet as it is. Not that this is a necessarily completely insurmountable problem, but. . . .
July 16th, 2009 at 12:53 am
And where would the nitrogen needed to dilute the atmospheric gasses come from? A Comet perhaps?
July 16th, 2009 at 5:24 am
#7 Obviously we would just fuse/fission the already present materials into the proper forms of matter.
#5 Well a giant shade seems a bit more feasible then moving the entire planet.
Also I believe mars is a little too small to hold a dense atmosphere thus making it some what less desireable. However since we’re engaging in massive engineering projects, I suppose we could just add some mass to it.
Then again this may not be cost effective and we’d actually just end up constructing a Dyson’s Sphere (s?).
July 16th, 2009 at 7:24 pm
@ Rebecca,
While changing planetary orbits is far beyond us technologically, shading the planet is possible now (though very expensive). There are proposals out there to shade Earth as a response to global warming.
Also, I thought that changing orbits was a no-no anyhow? Something about the orbital lanes being the only ones stable relative to the other planets. If you just altered the orbit of Venus, you get instabilities in the new orbit and eventually Venus gets ejected from the solar system.
There’s an orbital mechanics ratio for most of the planets. Each planet is twice as far from the Sun as the next planet in. If you mess with the ratio you are asking for trouble.
July 17th, 2009 at 3:06 am
maybe if you could find a way to take the co2 out of the air, you wouldn’t have to shade it. The temperature would drop, the atmosphere would thin.
Freeze the CO2, and ship it off to mars. heh
July 18th, 2009 at 6:06 pm
Don’t assume Venus was always in its current position. It might have been ripped from Jupiter in pre-historic times (legends point to this) and moved past Earth to its present locale.
October 9th, 2011 at 8:08 am
I HAVE ALWAYS BELIEVED THAT VENUS WAS MUCH MORE LIKELY TO HAVE BEEN THE PLANET THAT WAS CAPABLE OF HUMANOID LIFE. HAD WE INVESTED TIME AND MONEY THERE BY NOW WE WOULD KNOW MORE ABOUT THE CHANGES THAT TOOK PLACE HERE ABRUPTLY, THOUSANDS OF YEARS AGO. IF ANY ONE CAME TO THE EARTH, IT WOULD HAVE BEEN VENUTIANS, NOT MARTIANS.