One of Jupiter’s natural satellites, which goes by the name Io, is perhaps one of the Solar System’s most volcanically-active bodies. Since Io is so far away, we don’t exactly have the optimal circumstances to observe it up close and in person. Instead, we resort to using incredibly powerful telescopes, which allow astronomers to observe things from a distance from right here on Earth.
Image Credit: NASA
The Large Binocular Telescope Observatory in Arizona made it possible for astronomers to capture imagery of a massive lava lake on Io’s surface that is said to cover an area of more than 8,300 square miles. The images were captured as another of Jupiter’s moons, Europa, passed in between Io and our line of sight back in 2015.
For comparison, and to give an idea of how large that really is, Lake Ontario on Earth has an area of just 7,300 square miles. Named Loki Patera, this molten lava-filled crater is up to one million times larger than any lava lake found on the surface of the Earth today.
As Europa passed in between our line of sight with Io, it blocked out some of the infrared light that was being radiated from Io. Through this, researchers were able to spot important temperature signatures coming from heat radiation originating from volcanoes on Io’s surface. The findings appear in the journal Nature.
"This is the first useful map of the entire patera," study co-author Ashley Davies, an astronomer at NASA's Jet Propulsion Laboratory, said 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."
Notably, as the moon was seen transiting Io’s surface, astronomers picked up temperature differences that appear to provide evidence for either overturning lava or periodic volcanic eruptions. The debate rages on about which is causing it, but the evidence is there nonetheless.
The differences revealed a temperature increase from 26º Fahrenheit on the Western side of the moon to 134º Fahrenheit on the Eastern side, suggesting that two individual waves of overturning lava had swept across the surface in a West-to-East movement. The motion allowed the West to cool down, as the East was still hot from activity.
While Io is certainly a place of interest in our Solar System, it’s much too hot to put a lander on its surface. Fortunately, we can continue to observe it from afar with telescopes from Earth, and perhaps even future spacecraft that will visit the Jovian system like Juno is right now.
Europa is expected to intercept Io’s infrared light again sometime in 2021, so we’ll get another opportunity again soon enough to observe the volcanic activity on the moon’s surface. It ought to be interesting to see how the next batch of data compares to the most recent, as this will allow us to study any possible changes in Io's surface over time.