Over the past several years the formation of our own solar system has been of high importance in scientific circles. Many scientists have focused their attention on the inner four planets, and found that we bounced around like a ball in a pinball machine in our early formative years.
Now an impact theory is arising as an explanation for the formation of our evil twin: Venus (xray image left).
J. Huw Davies of the University of Cardiff in the UK, has posited that a collision of two embryonic planets may have crashed together to form what we now know as Venus -a planet almost devoid of water, an extreme greenhouse atmosphere, and a relatively smooth surface.
Not a new theory, a Venus impact scenario had been ruled out due to a lack of debris left behind; ie, a moon. However Davies believes that in the case of Venus’ collision, there would have been no fragments left behind. In fact, he believes that two smaller-sized planet embryos coming together in such a collision would simply fuse together to form a larger planet.
The theory is that in the case of giant planets, coming together at such velocity, the heat generated would the two objects would fuse together, rather than shatter apart like our backyard clods of dirt.
Those who believe a collision event was not the creator of what we know as Venus today point to the fact that the erosion of hydrogen in Venus’s atmosphere could have been the result of solar winds rather than a head on collision. However, Davies believes that this would have been too slow, and suggests that during the impact the water on the planet would have reacted with iron to form iron oxides and release hydrogen.
Venus is more than just Earth’s evil twin though, as it comes with a trio of oddities that Davies believes could be solved by his collision theory.
First of all, Venus’s surface is very flat and unmarked – very much unlike the other inner system planets which have been battered by billions of years of meteor impacts. A head on collision as theorized by Davies could explain this away as the result of a clean slate created by the collision.
Secondly, Venus rotates very slowly and in a clockwise direction – unique in solar system planets. Once again the collision theory explains this. If the two bodies that eventually collided had been rotating in different direction before impact, they would have created a planet out of kilter with the rest of the solar system.
Finally, Venus’s lack of tectonic plates could once again be explained in this theory, considering the outrush of water upon impact. Tectonic plates on Earth rely partly on water to create the shear zones where the plates slip; without the water, does this explain Venus’s lack of plates?
"The idea is amazingly simple," says Gareth Collins, a planetary impact specialist at Imperial College London. "It's incredible that no one thought of it this way before."
Thankfully, unlike many space related science theories, Davies has provided a simple test to run. If Venus’s water was not in fact lost in one big collision impact, then rocks at its surface will contain water locked in to their structure. Bingo Presto!
Posted by Josh Hill.