It is an important insight for planned missions to the icy moon, which will investigate whether a world hundreds of millions of kilometers away from the sun can harbor life.

A few years ago, researchers came up with decisive proof: Jupiter’s moon Europa sprays water vapor into space like a leaking garden hose. The water makes its way up from a subterranean ocean, where it is then blown away through cracks in the ice sheet. Now researchers are coming in a new study to a surprising discovery. Because although water vapor appears to be widespread in Europe, strangely enough it only occurs in one hemisphere.

More about moon Europe

The monstrous planet Jupiter has dozens of moons, but Europa is undoubtedly the most fascinating example. Many researchers see the moon as the place in our own solar system to look for extraterrestrial life. If you take a quick look at the moon, you may be surprised at first sight. You wouldn’t think that life hundreds of millions of kilometers away from the sun could be possible. In addition, Europe is covered with a thick ice sheet; water ice is as hard as rock. Thus, the planet does not look so habitable. But there is strong evidence that beneath that ice sheet is a global, liquid-water-filled ocean in which life may have originated and thrived.

Previous observations of water vapor on Europa have been linked to plumes bursting through the ice, as photographed by the Hubble Space Telescope in 2013. These plumes can best be compared to geysers on Earth, even though the ones on Europa stretch nearly 100 kilometers. above the surface. They inject temporary “blobs” of water vapor into the moon’s atmosphere, where the pressure is 100 billion times lower than Earth’s air pressure.

Study

In a new study, researchers looked at Hubble observations collected between 1999 and 2015. Thanks to observations in ultraviolet, the team discovered an abundance of oxygen — one of the constituents of water — in Europa’s atmosphere. By then studying the strength of the emission at different wavelengths, the researchers were able to deduce the presence of water vapor.

Ice

The team makes a striking discovery. Because the atmosphere of Europe has been harboring water vapor for years; much more than expected. Unlike the geysers, this water vapor does not come from the interior of Europa, but sunlight causes the surface ice to sublimate (that is, transform directly from solid to vapor with no liquid phase).

One hemisphere

Strangely enough, this water vapor is only limited to one hemisphere. The results show that the water vapor can only be found on one side of the moon; the part of the moon that is always opposite to its direction of motion. Why? Nobody knows.

icy moons

Despite the questions associated with the discovery, researcher Lorenz Roth sees the findings as rosy. “The observation of water vapor in one hemisphere of Europe advances our understanding of the atmospheres of icy moons,” he says. In addition, water vapor was recently discovered in the atmosphere of the neighboring moon Ganymede. Although the detection on Europe is somewhat more surprising than on Ganymede, according to Roth, because the surface temperatures on Europe are much lower.

The new discovery will help shape planned missions to Jupiter’s very interesting moon. Because Europe is such a promising place for life, the American space agency is sending out a real spacecraft. The mission, called Europa Clipper, will make dozens of flybys around the icy moon to learn more about the ocean beneath the thick ice crust. ESA will also subject Europe to a closer inspection with the Jupiter Icy Moons Explorer spacecraft. Hopefully it will then become clear whether this wonderful world at a great distance from the sun, in some way harbors life. In addition, understanding the formation and evolution of Jupiter and its moons will also help astronomers gain insight into Jupiter-like planets orbiting other distant stars.