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NASA’s Juno mission discovered that Jupiter’s icy moon Europa produces 1,000 tons of oxygen every 24 hours.
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It is enough to keep a million people breathing for a day but is much less than previously thought.
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These new data may reduce the chances that Europa could support life in the vast underground ocean.
About 400 million miles away, floating in deep space, is a water world called Europa that produces 1,000 tons of oxygen every 24 hours. That’s enough oxygen to keep a million people alive for a day, NASA reported this week.
However, these new estimates, published in the peer-reviewed journal Nature Astronomy, are not intended to determine how many people could live on this moon of Jupiter. They are helping scientists determine whether or not Europa hosts life of its own.
“We think Europa is the most likely place to look beyond Earth today,” said Curt Niebur, NASA’s chief scientist for outer-planet exploration who was not involved in the study.
If there are life forms on Europa, they may look like microbes, or perhaps something more complex, according to NASA. But they wouldn’t be visible from the surface, which is a frozen desert.
It is more likely that they would be in a large ocean under the surface of the moon that could contain as much as twice the water of Earth.
Although water is one key ingredient to life as we know it, it is not the only one. There is a laundry list of other chemicals that scientists are looking for – oxygen being one of them.
Now, the most precise estimate of Europa’s oxygen production to date has been taken by NASA’s Juno spacecraft, which is currently flying around Jupiter and its moons. And it turns out to be much less than we thought.
The latest estimate of 1,000 tons of oxygen every 24 hours is more than 86 times less than some previous estimates. And Europa’s habitus may be in doubt about these new details.
How does Europa produce oxygen
Oxygen production looks very different on Europa than on Earth. While Earth gets its oxygen from photosynthesis, Europa’s is a product of its parent planet Jupiter.
Jupiter emits powerful radiation that showers Europa with high-energy particles. These particles then interact with frozen water ice (H2O) on the surface of the moon.
The interaction splits the H2O molecules apart into hydrogen and oxygen gas. But where that oxygen goes is the big question. Some of it may become ice, some may escape into space, and some may travel down to Europa’s surface oceans.
If enough oxygen reaches the ground, it would mean that Europa’s oceans have one of the vital ingredients for life as we know it. “But that’s a big question mark for us,” because the oxygen can end up in a lot of different places, Niebur said.
What NASA’s Juno mission has done is shed more light on the total amount of oxygen generated by Europa’s surface. However, it is not yet clear how much, if any, flows into the underground ocean.
Measuring oxygen on Europa
To measure the amount of oxygen generated by Europa’s surface, scientists used the Jovian Auroral Distributions Experiment (JADE) instrument on board Juno.
JADE was designed to measure charged particles in Jupiter’s auroral regions. But when Juno flew by Europa in September 2022, JADE managed to measure the charged particles blown out of the moon’s atmosphere for the first time ever.
Using the JADE data, the scientists estimated the total amount of hydrogen gas (not oxygen) in Europa’s thin atmosphere. Since there is one oxygen atom for every two hydrogen atoms in a water molecule, scientists could use the hydrogen gas data to calculate the amount of oxygen generated at the surface.
“This has refined and narrowed our understanding of how much oxygen is produced at the surface,” said study lead author Jamey Szalay, a space physics researcher at Princeton University.
“But we don’t know how much of it leaves the surface and how much of it makes its way to the ocean,” Szalay said. NASA’s next Europa mission, Clipper, may bring us closer to answering that question.
A constant search for the possibility of life
NASA’s Europa Clipper mission is scheduled to launch in October 2024. Its main objective is to determine whether Europa is habitable or not.
Clipper will carry instruments that will help them reveal Europa’s inner structure, such as its subsurface radar. With this instrument, NASA scientists will peer down miles below the crust to identify features that could help determine whether oxygen is reaching the subsurface ocean, Niebur told BI.
“Clipper is an extremely exciting mission, with important science objectives that will revolutionize our understanding of the ice shell, the subsurface ocean, and how they interact with each other,” said Szalay.
While it improves our understanding of whether or not the moon is habitable in Europa’s subsurface ocean, it will not automatically confirm whether life is, or could be, on Europa.
“The amount of oxygen available on Europa is not a binary switch that you flip to decide whether life could be present or not,” Niebur explained.
He pointed out that life on Earth existed for about 1.5 billion years without oxygen. If it could happen here, it could also happen on this distant moon.
For the Juno mission, Szalay will continue to work through the data they recovered during this Europa flyby.
“For years to come, we’ll be digging through this and learning everything we can,” he said.
Read the original article on Business Insider
