Recent maps of the surface of Venus suggest that early in the planet's history, it may have had a ocean, as well as a crust that underwent fragmentation and replenishment, just as Earth's does.
That's the word from a team of scientists led by Nils Müller, a researcher at the University of Münster and at the DLR Institute in Berlin. The group built its map from data gathered by the European Space Agency's Venus Express orbiter.
The map Müller & Co. put together provides some hints as to the chemical composition of the surface on Venus, particularly the highlands, where no lander has ever touched down to analyze the surface.
Rocks on two plateaus gave off infrared signatures similar to those given off by granite on Earth. Granite is reprocessed rock, forming under the intense heat and pressure that builds up when one crustal plate grinds beneath another.
The new map doesn't constitute proof, Müller cautions. "All we can really say at the moment is that the plateau rocks look different from elsewhere."
But, he adds, "If there is granite on Venus, there must have been an ocean and plate tectonics in the past."