Search for habitable moons in the solar system is heating up

The search for habitable moons in the solar system is heating up

In the search for life beyond Earth, one of the most exciting potential locations to explore is Saturn’s icy moon Enceladus. With its thick icy crust covering a liquid water ocean, the moon is notable both for the plumes of water spraying from its surface and the fact that it could potentially support life. Now, the search for habitable environments is heating up as astronomers discovered that Enceladus hosts phosphorus, which is an important element for life.

The research used data from the Cassini mission, which performed multiple flybys of Enceladus in the mid-2000s, investigating the water plumes and cryovolcanoes that dot its surface. The spacecraft also flew through one of the outer rings of Saturn, which carries particles that are sent out by the Enceladus plumes. While much of the Cassini data has been studied extensively, this new research is the first time that phosphorus has been detected in it.

During a 2005 flyby, NASA’s Cassini spacecraft took high-resolution images of Enceladus that were combined into this mosaic, which shows the long fissures at the moon’s south pole that allow water from the subsurface ocean to escape into space. — During a 2005 flyby, NASA’s Cassini spacecraft took high-resolution images of Saturn’s icy moon Enceladus that were combined into this mosaic, which shows the long fissures at the moon’s south pole that allow water from the subsurface ocean to escape into space. NASA/JPL/Space Science Institute

“We previously found that Enceladus’ ocean is rich in a variety of organic compounds,” said lead researcher Frank Postberg of Germany’s Freie Universität Berlin in a statement. “But now, this new result reveals the clear chemical signature of substantial amounts of phosphorus salts inside icy particles ejected into space by the small moon’s plume. It’s the first time this essential element has been discovered in an ocean beyond Earth.”

Phosphorus can form organic compounds, which are chemicals with carbon or hydrogen bonds that are important for life. Phosphorus forms the basic structures of DNA, so finding it supports the idea that the moon could be potentially habitable.

The researchers make it clear that they haven’t found life on Enceladus, but that the required ingredients seem to be there. “Having the ingredients is necessary, but they may not be sufficient for an extraterrestrial environment to host life. Whether life could have originated in Enceladus’ ocean remains an open question,” said Christopher Glein of the Southwest Research Institute.

As well an making the moon an intriguing target for further study, the findings about Enceladus also demonstrate that we could investigate other icy moons for habitable conditions, such as Jupiter’s moons Europa, Ganymede, and Callisto. The European Space Agency’s JUICE mission is currently on its way to investigate these targets and to look for evidence of potentially habitability there.

The research is published in the journal Nature.

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