Friday, 21 September, 2018

Europa water plume: Another step toward living on a moon

ImageNASA’s Galileo spacecraft appears to have flown through a plume erupting from Jupiter’s moon Europa more than 20 years ImageNASA’s Galileo spacecraft appears to have flown through a plume erupting from Jupiter’s moon Europa more than 20 years
Theresa Hayes | 15 May, 2018, 01:56

Then in 2012 the Hubble Space Telescope spotted what looked like plumes of material being ejected from Europa's southern polar region. Fifteen years after the NASA probe burned up in Jupiter's atmosphere, newly analyzed magnetic and plasma data from the mission have bolstered evidence that Europa, the planet's ice-bound moon, is likely venting water into space.

According to Jai, data studied here showed "compelling independent evidence that there seems to be a plume on Europa".

The tallest of the plumes was so powerful that it extended 193km above the moon's surface; Old Faithful, the famous geyser at Yellowstone, reaches 56 metres.

Jupiter's icy moon Europa is slightly smaller than Earth's moon. Scientists think this, and the heat provided by the constant gravitational kneading of Europa's core by Jupiter and its other moons, makes Europa a prime candidate for life, albeit on a microbial scale. Subsequent studies revealed the building blocks of life were present in that world's subsurface ocean.

At the time the blip in the data was unexplained but it is now believed it was a water plume.

Last month researchers found two lakes hidden under thick ice in Canada that could be similar to the conditions found on Jupiter's moon Europa. If researchers want to know if some form of life has indeed taken root inside the planet, studying those plumes may be the easiest way to prove it.

Scientists thought that they may have been able to find data about water plume in Galileo's data.

During its time at Jupiter, Galileo performed 11 flybys of Europa.

Verifying the existence of the plumes is therefore of utmost importance and that proof is one step closer to being realised, as a team of researchers from the U.S have reconstructed a plume in 3D based on data taken by the Galileo spacecraft as it skimmed approximately 400 kilometres above the moon's surface in December 1997. Both of these observations provide strong evidence of a plume, Jia said.

In addition, "to make sense of the observations, we had to really go for sophisticated numerical modeling" techniques, he told Space.com.

In a paper in the journal Nature Astronomy Jia describes how his team build custom 3D modelling code to work out a plume's density and properties, adding in the magnetic data from the Enceladus plume probe.

A mission called Europa Clipper was proposed several years ago.

They could also provide a target destination for future missions to the outer solar system, including the European Space Agency's JUICE mission and Europa Clipper, which could get additional funding through a spending bill now working its way through the US Congress.

If Galileo already flew within the immediate vicinity of the jets without even trying, NASA could certainly achieve the same feat with a new probe created to specifically to sample the icy plumes in the hunt for microbial life or some other organic proof that something is alive in Europa's depths.

The evidence gathered to date suggests that the processes producing Europa's plumes - if they do indeed exist - may not be continuous like the geysers of Enceladus but instead intermittent.

The results were in "satisfying agreement", Jia said.