Moving, shaking and spraying taking place in our own solar system
From our vantage point on Earth, it’s sometimes hard to see what else is happening in the solar system. With the literal exception of the Sun, our small planet seems to be the hot spot in our part of the galaxy, with meteorites, dramatic weather, and a molten core that keeps the planet’s surface sliding all over the place. Of course, a closer look can easily reveal a fair amount of activity in other places, ranging from geysers blasting water 125 miles into space to a literally shrinking planet. And that’s just from this week.
The geysers were spotted blasting out of the icy shell of Jupiter’s moon, Europa. While around the same size as our own Moon, Europa may possibly be home to twice as much liquid water as Earth’s oceans, locked under a layer of ice. We don’t know how thick the ice even is, but fortunately for remote observations, this outer layer seems to have sprung a few leaks that intermittently spray what appears to be water out into space before falling back to the moon’s surface. These geysers should make future study of the moon’s water much easier, since it exposes water otherwise hidden away to both telescopes and a potential probe to be launched in 2022.
If this all seems somewhat familiar, it’s because this isn’t actually the first time this kind of activity has been seen in our solar system, or even on Europa itself. Geysers of water vapor and dust have also been found by the Cassini spacecraft spewing out of Saturn’s moon, Enceladus. The first sighting of Europa’s possible geysers was in 2012. This study which observed the moon with a completely different set of measurements in order to look for traces of an atmosphere on Europa, strongly bolstered the 2012 study, agreeing on metrics like mass and volume of the geysers. Both studies support the idea that the small moon is chemically, if not mechanically, active, and worth a closer look as a potential home for forms of life.
In contrast to Europa’s sporadic bursts of activity, Mercury seems to be contracting. Studies of the tiny planet’s surface had found features called scarps, which are a bit like wrinkles in the outer crust of the planet, almost like the wrinkling in a balloon as it starts to loose air. Most of Mercury’s scarps seemed to be fairly old, in many cases being pock-marked with craters and other more recent geological activity. However, in some of the final data obtained by the Messenger spacecraft, researchers found small, fresher scarps around the planet, indicating that the planet’s surface is still in flux. As the small planet’s core continues to slowly cool, it seems that the planet continues to shrink, triggering seismic activity in the process.
Source: NASA's Hubble Spots Possible Water Plumes Erupting on Jupiter's Moon Europa, Hubble Site.org