Scientists have revealed the most complete look ever at the largest lake on Io, a stunning glimpse into this moon of Jupiter that’s the most volcanically active place in the Solar System.
In a paper published in Nature, researchers led by the University of California, Berkeley (UCB) described how they were able to study the largest lake on Io not from spacecraft imagery, but from watching its neighboring moon Europa pass in front in March 2015, known as an occultation.
They were able to see waves move across Loki Patera, Io’s biggest lava lake at more than 200 kilometers (125 miles) across. For comparison, Earth’s biggest lava lake is no more than 200 meters (650 feet) across, one million times smaller in volume.
“We saw two waves within the patera that hadn’t been seen before, with different velocities and start times,” Katherine de Kleer from the University of California, Berkeley, the lead author on the paper, told IFLScience. “This tells us there’s some complex system underneath the volcano.”
Europa seen passing in front of Io and Loki Patera (the upper bright spot). LBTO
The lake was seen increasing in temperature from one side to the other, from 270 Kelvin in the west to 330 Kelvin in the east, suggesting it had “overturned” from west to east.
This is the process by which a crust forms on the surface, and then becomes unstable and sinks into the lava, exposing new magma while pulling other crust under with it. The magma then cools, forms new crust, and the process repeats over about five months. It is thought it might be accompanied by fire fountains, which are also seen on Earth.
“This is the first useful map of the entire patera,” said co-author Ashley Davies from NASA’s Jet Propulsion Laboratory in California in a statement. “It shows not one but two resurfacing waves sweeping around the patera. This is much more complex than what was previously thought.”
There's also an island present in the middle of the lake, seen here