Hubble spots persistent water vapor on Europa — but only in one hemisphere

By Georgina Torbet October 16, 2021

One of the most promising locations to search for life in our solar system isn’t on a planet — it’s on a moon, specifically Jupiter’s moon Europa. Now, new evidence from the Hubble Space Telescope shows that there seems to be persistent water vapor spread across one of Europa’s hemispheres, where it is being sublimated from ice on the surface. But why this vapor is only present on one side of the moon remains unclear.

Europa is particularly promising as a location to look for life because it is thought to host a liquid ocean beneath the icy crust of its surface. Previously, scientists had detected plumes of water vapor on Europa which seem to be erupting through the ice, similar to how geysers throw up water on Earth. But this recent discovery suggests there is a second source of water vapor on Europa as well.

This photograph of the Jovian moon Europa was taken in June 1997 at a range of 776,700 miles by NASA’s Galileo spacecraft. NASA/JPL/University of Arizona

The recent research looked at Hubble data collected between 1999 and 2015 and found long-term presence of water vapor spread over a large area of the moon. It is present only in Europa’s trailing hemisphere, which is the half of the moon which is opposite the direction in which it is moving.

Recommended Videos

A similar analysis to the Hubble data about Europa was also recently used to find water vapor in the atmosphere of Jupiter’s moon Ganymede by the same researcher, Lorenz Roth of the KTH Royal Institute of Technology, Space and Plasma Physics, Sweden.

“The observation of water vapor on Ganymede, and on the trailing side of Europa, advances our understanding of the atmospheres of icy moons,” said Roth in a statement. “However, the detection of a stable water abundance on Europa is a bit more surprising than on Ganymede because Europa’s surface temperatures are lower than Ganymede’s.”

Roth found that, even in the chilly temperatures of -260 degrees Fahrenheit on Europa, the ice was sublimating (changing from solid to gas without becoming a liquid) in the sunlight. However, the strangest part of this phenomenon — why it is happening only on one hemisphere — remains a mystery.

To learn more about this intriguing moon, the European Space Agency’s Jupiter Icy Moons Explorer (JUICE) mission will be traveling there after its launch next year, along with NASA’s Europa Clipper mission, set to launch in 2024.

The research is published in the journal Geophysical Research Letters.

Topics

Georgina Torbet

Space Writer

Georgina has been the space writer at Digital Trends space writer for six years, covering human space exploration, planetary…

Space

Hubble takes first image since switching to new pointing mode

This NASA Hubble Space Telescope features the galaxy NGC 1546.

This NASA Hubble Space Telescope captured an image of the galaxy NGC 1546. NASA, ESA, STScI, David Thilker (JHU)

The Hubble Space Telescope has been through some troubles of late, and the way that it operates had to be changed recently to compensate for some degraded hardware. The telescope's three gyros, which help it to switch between different targets in the sky, have been experiencing issues, with one in particular frequently failing over recent months. NASA made the decision recently to change the way that Hubble points, and it now uses just one gyro at a time instead of all three in order to preserve the two remaining gyros for as long as possible.

Space

Hubble will switch to a new mode to preserve its troublesome gyros

An STS-125 crew member aboard the Space Shuttle Atlantis captured this image of NASA’s Hubble Space Telescope on May 19, 2009.

An STS-125 crew member aboard the Space Shuttle Atlantis captured this image of NASA’s Hubble Space Telescope on May 19, 2009. NASA

The beloved Hubble Space Telescope will soon be changing the way it operates by limiting the speed at which it can target new objects in order to preserve its lifespan for as long as possible.

Space

Hubble catches a baby star pulsating in a triple star system

This NASA Hubble Space Telescope image captures a triple-star star system.

This NASA Hubble Space Telescope image shows a triple-star star system. NASA, ESA, G. Duchene (Universite de Grenoble I); Image Processing: Gladys Kober (NASA/Catholic University of America)

A gorgeous new image from the Hubble Space Telescope shows a triple star system, where three stars are working in tandem to create a reflection nebula. The trio of stars are located 550 light-years away, and include one particular star, HP Tau, that is like a younger version of our sun and will eventually grow up to be a similar hydrogen-fueled star in millions of years' time.