Magellan: Snapshots of Venus

December 24, 1991

What a statement: "We probably have a better global map of Venus now than we have of Earth, because most of the ocean basins on Earth are so poorly mapped." That's from Dr. Stephen Saunders, chief scientist on the Magellan project, which is surveying Earth's nearest neighbor by radar.

The first pictures from that radar imaging experiment, 14 months in the making, are stunning: Five-mile-high Maat Mons, only the second highest peak on the planet, surrounded by lava flows. Two-mile Gula Mons, small by Venusian standards, dominating a plain on which is stamped Crater Cunitz, named for astronomer Maria Cunitz. Deep, twisty channels up to 4,200 miles long on the surface of the planet.

The Magellan spacecraft has mapped 92 percent of Venus' surface. It is already halfway through another sweep from a different angle. That may help clear up questions created by the latest pictures, or it may lead to still more questions.

Is Maat Mons an active volcano, as John Wood of the Smithsonian Astrophysical Observatory has speculated? Or do the simulated "colors" created by combining Magellan's images with those of a Soviet spacecraft mean that the lava flows are something other than new deposits? Could the high winds, accompanied by temperatures hot enough to melt lead, really have left craters unmodified over 500 million to 600 million years, as the Jet Propulsion Laboratory's Dr. Saunders thinks? And just what could have carved those deep channels?

Such questions and the drive to answer them have been the rocket fuel that has propelled modern science from the time Galileo's telescope proved the Earth wasn't the center of the universe. Answering them often tells scientists more than they thought they would know about the evolution of planet Earth, as well as filling up the store of general knowledge about the universe around us.

It is a worthy quest, all the more exciting because Venus' cloudy atmosphere kept its amazing face shrouded for so long. Space science has endured some rocky days as the Hubble Space Telescope disappointed its planners and the Galileo probe's antenna stuck half-unfolded, delaying transmission of its pictures asteroid Gaspra until it swings back by the Earth next year. So a success like Magellan is all the more welcome.

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