The Magellan spacecraft has discovered the longest known channel in the solar system on the surface of Venus - a geological groove longer than the Nile River, NASA reported Thursday.
Scientists at the space agency's Jet Propulsion Laboratory said they do not know what formed the channel, which measures about 1 mile across and runs for about 4,200 miles in a winding, smoothly curved course across the plains of Venus."The very existence of such a long channel is a great puzzle. If the long channel were carved by something slowing on the surface, the liquid must have had unusual properties," said Steve Saunders, the project's scientist.
The channel was detected by the imaging radar Magellan is using to map the surface of Venus, which is obscured from view by thick, yellowish clouds. Venus is the nearest planet to Earth and is the second planet from the Sun.
Shorter channels have been seen on many plains on other parts of Venus, some of which terminate in lava flows that suggest they were carved out by lava from a volcanic eruption.
But Saunders said it is unlikely that lava, even at very high temperatures, would have the very high rate of flow needed to form the newly discovered channel.
No similar channels are now known on Earth, NASA said.