(ORDO NEWS) — According to current theory, comets are a bit like space storks that delivered the ingredients from which life could be created to the newborn Earth billions of years ago.
Now a new study by scientists from the University of Texas, Caltech and Williams College has found that comets may play a similar role in delivering other life-giving compounds to other nearby worlds in this case, reactive chemicals called oxidizers penetrate through the ice crust into the oceans of Jupiter’s moon Europa.
Even if the comet doesn’t completely break through the ice, its impact could help carry oxidizers to Europa’s surface all the way to the liquid below, where they could help support whatever life might be lurking out there in the darkness.
Computer models indicate that an asteroid or comet impact should only penetrate halfway through 15–15 miles of ice 25 kilometers (10 to 15 miles) thick forms a massive melting chamber that will continue until the end of the journey.
“Once you get enough water, you just drown,” he says. computer engineer Evan Carnahan of the University of Texas at Austin. “It’s like the Titanic 10 times.”
When it comes to looking for life beyond Earth, even our own solar system is a major challenge. There is simply nothing that has the unique conditions of our home world. The earth is truly unique.
But there are worlds that may have the necessary qualities that reflect the life-supporting environment on Earth. One of them is Europa, along with other icy moons – Saturn’s Titan and Enceladus.
These worlds are far from the Sun and far outside the temperate habitable zone. But that chilling distance from the Sun, combined with the extreme darkness of the ocean depths, means that life won’t be able to rely on a photosynthetic food web, as the vast majority of life on Earth does.
However, some forms of life thrive in the lightless depths of the Earth. Around the hydrothermal vents, spewing heat and chemicals from the ocean floor, clusters an entire ecosystem based on chemosynthesis: chemical reactions are used to produce energy, not sunlight.
Europa is believed to have hydrothermal vents, powered by the stretching and contraction of the moon ‘s core as a result of its gravitational interaction with Jupiter, creating an internal heat source.
But scientists believe that any carbon-based life out there may need oxidizers to survive. These electron-accepting substances are formed on Europa’s surface by exposure to solar radiation and light, but their use is limited to an ecosystem separated from the surface by a thick ice shell.
One potential transport mechanism is the impact of comets and asteroids, which will cause intense heat and melt the ice, allowing the oxidizers to sink down. After all, there are a few impact craters on Europa, though not many, because tectonic activity creates ice plumes and volcanoes that cover them rather quickly.
However, the moon is no stranger to bombardment, and those impact craters that have been identified show concentric ripples, suggesting significant melting followed by subsurface movement after the impact.
To determine whether these impacts would be sufficient to carry the oxidizers, Carnahan and his team threw mathematically modeled rocks at a simulated Europa and observed the events after the impact. Instead of forming a shallow pocket of meltwater that then refrozen, this meltwater – denser than the surrounding ice – sank down.
“We caution against the idea that you can support very large volumes of meltwater into shallow subsurface layers without sinking,” says Carnahan.
According to the team’s simulations, if this impact reaches half of Europa’s ice sheet, 40 percent of the meltwater will eventually drain into the ocean. This matters not only for Europe, but also for other icy worlds with subsurface oceans.
“This study shows that impact melt flooding is a viable, reliable, and probably widespread mechanism for the transfer of materials from surface to surface. in the ocean of Europe,” the researchers write in their article.
“While this study was focused on Europa, viscous sinking of shock melts into the ocean occurs for all ice thicknesses and viscosities studied here, and is thus likely to occur on other icy worlds like Europa, such as Titan.”
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