On Jupiter's moon Europa, 'chaos terrains' could be shuttling oxygen to
ocean

Date:
March 24, 2022
Source:
University of Texas at Austin
Summary:
Researchers have built the world's first physics-based computer
simulation of oxygen transport on Europa, finding that it's possible
for oxygen to drain through the moon's icy shell and into its ocean
of liquid water -- where it could potentially help sustain alien
life -- by hitching a ride on salt water under the moon's 'chaos
terrains.' The results show that not only is the transport possible,
but that the amount of oxygen brought into Europa's ocean could
be on a par with the quantity of oxygen in Earth's oceans today.



FULL STORY ==========================================================================
Salt water within the icy shell of Jupiter's moon Europa could be
transporting oxygen into an ice-covered ocean of liquid water where
it could potentially help sustain alien life, according to a team of researchers led by The University of Texas at Austin.


==========================================================================
This theory has been proposed by others, but the researchers put it to the
test by building the world's first physics-based computer simulation of
the process, with oxygen hitching a ride on salt water under the moon's
"chaos terrains," landscapes made up of cracks, ridges and ice blocks
that cover a quarter of the icy world.

The results show that not only is the transport possible, but that the
amount of oxygen brought into Europa's ocean could be on a par with the quantity of oxygen in Earth's oceans today.

"Our research puts this process into the realm of the possible," said
lead researcher Marc Hesse, a professor at the UT Jackson School of
Geosciences Department of Geological Sciences. "It provides a solution to
what is considered one of the outstanding problems of the habitability
of the Europa subsurface ocean." The study was recently published in
the journal Geophysical Research Letters.

Europa is a top spot to look for alien life because scientists have
detected signs of oxygen and water, along with chemicals that could
serve as nutrients.

However, the moon's ice shell -- which is estimated to be about 15 miles
thick -- serves as a barrier between water and oxygen, which is generated
by sunlight and charged particles from Jupiter striking the icy surface.



==========================================================================
If life as we know it exists in the ocean, there needs to be a way for
oxygen to get to it. According to Hesse, the most plausible scenario based
on the available evidence is for the oxygen to be carried by salt water,
or brine.

Scientists think that chaos terrains form above regions where Europa's
ice shell partially melts to form brine, which can mix with oxygen from
the surface. The computer model created by the researchers showed what
happens to the brine after the formation of the chaos terrain.

The model showed the brine draining in a distinct manner, taking the form
of a "porosity wave" that causes pores in the ice to momentarily widen -- allowing the brine to pass through before sealing back up. Hesse compares
the process to the classic cartoon gag of a bulge of water making its
way down a garden hose.

This mode of transport appears to be an effective way to bring oxygen
through the ice, with 86% of the oxygen taken up at the surface riding
the wave all the way to the ocean. But the available data allows for a
wide range of oxygen levels delivered to Europa's ocean over its history
-- with estimates ranging by a factor of 10,000.

According to co-author Steven Vance, a research scientist at NASA's Jet Propulsion Laboratory (JPL) and the supervisor of its Planetary Interiors
and Geophysics Group, the highest estimate would make the oxygen levels
in Europa's ocean similar to those in Earth's oceans -- which raises hope
about the potential for that oxygen to support life in the hidden sea.



========================================================================== "It's enticing to think of some kind of aerobic organisms living just
under the ice," he said.

Vance said that NASA's upcoming 2024 Europa Clipper mission may help
improve estimates for oxygen and other ingredients for life on the
icy moon.

Kevin Hand, a scientist focused on Europa research at NASA JPL who
was not part of the study, said that the study presents a compelling explanation for oxygen transport on Europa.

"We know that Europa has useful compounds like oxygen on its surface,
but do those make it down into the ocean below, where life can use
them?" he said. "In the work by Hesse and his collaborators, the answer
seems to be yes." The research was funded by NASA, the National Science Foundation and the American Chemical Society Petroleum Research Fund.

In addition to the Jackson School, Hesse is also a researcher at the
UT Center for Planetary Systems Habitability and the Oden Institute for Computational Engineering and Sciences.


========================================================================== Story Source: Materials provided by University_of_Texas_at_Austin. Note: Content may be edited for style and length.


========================================================================== Related Multimedia:
* Chaos_terrain_on_the_surface_of_Jupiter's_moon_Europa ========================================================================== Journal Reference:
1. Marc A. Hesse, Jacob S. Jordan, Steven D. Vance, Apurva
V. Oza. Downward
Oxidant Transport Through Europa's Ice Shell by Density-Driven
Brine Percolation. Geophysical Research Letters, 2022 DOI:
10.1029/2021GL095416 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220324143808.htm

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