Venus may have been a land of volcanoes?

April 9th, 2010 - 10:25 pm ICT by IANS  

Washington, April 9 (IANS) A new research suggests that the planet Venus could have been resurfaced by volcanoes.
The second rock from the sun appears to have been volcanically active; perhaps within the past several hundred years, and more certainly within the last 2.5 million years, the Christian Science Monitor reported Thursday.

The type of volcanism on Venus appears to be quite similar to the volcanism building in the Hawaiian Islands, said Sue Smrekar, a researcher at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

The conclusion comes from an attempt to solve a longstanding puzzle: Why is Venus’s surface virtually crater free?

The inner planets got pummeled by objects knocked out of the asteroid belt or the more-distant Kuiper Belt during a period early in the solar system’s history known as the Late Heavy Bombardment.

On Earth, those craters have been erased by plate tectonics - the constant movement and recycling of large patches of wandering crust that make up the Earth’s surface.

But scientists have found that tectonics need a large amount of water in the crust to work, and measurements suggest Venus’s crust is too dry.

The result appears to undermine a competing theory on why Venus lacks large amounts of craters: that the planet resurfaced itself in a massive overturning of the crust at some point in the past, burying the cratered surface under a fresh layer of lava.

Still, the new conclusions are “not a tidy story”, Smrekar acknowledges.

What scientists think they know about weathering processes on Venus has come from lab experiments, and the results from those experiments don’t line up perfectly with the timeline scientists think they are seeing on Venus.

“We believe our explanation is the correct explanation,” she says, “but we haven’t been able to reproduce it in the lab.”

The broad age bracket the team has placed on active volcanism on Venus represents a maximum, averaged over the entire planet. But, she adds, “It could be happening today.”

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