Radiation makes a bright number on Jupiter’s moon

The icy, ocean-filled moon Europa, orbits Jupiter, it withstands the relentless beat of radiation. Jupiter scatters the surface of Europa day and night with electrons and other particles, bathing it in high-energy radiation. But as these particles pound the lunar surface, they are probably doing something else: making Europa glow in the dark.

New research by scientists at NASA’s Jet Propulsion Laboratory in Southern California will reveal what the zigzag will look like first, and what it could reveal about the formation of ice on the surface of Europe. Different alkaline compounds react differently to radiation and emit their own unique glitter. For the naked eye, this glow will sometimes look greenish, sometimes slightly blue or white and bright of different materials, depending on what material it is.

Scientists use spectrometers to separate light into wavelengths and to associate “different signatures” or spectra with different ice formations. Most observations using a spectrometer on a moon like Europa are made using sunlight reflected on lunar days, but these new results illuminate what Europa will look like in the dark.

“We were able to predict that this night’s side of the ice glow could provide additional information about the formation of the European surface. How that formation changes could indicate whether the conditions are right for Europe’s lifetime,” the work published in November said. Chief author JPL’s Murthy Gudpati said. 9 in Nature astronomy.

That’s because Europa has a huge, global inland ocean that can go to the surface through a thick crust of ice moons. By analyzing the surface, scientists can learn more about what is below.

Twinkling light

Scientists have speculated from previous observations that the surface of Europe may have been formed from a mixture of ice and commonly known salts on Earth, such as magnesium sulfate (Epsom salt) and sodium chloride (table salt). New research shows that in conditions like Europa, glow is produced by incorporating that salt into water ice and blasting it with radiation.

That wasn’t much of a surprise. It is easy to imagine irradiated surface glowing. Scientists know that luminosity is caused by electrons penetrating the surface and stimulating the following molecules. When those molecules rest, they release energy as visible light.

“But we never imagined we would see what we saw,” said JPL’s Brianna Henderson, who co-authored the research. “When we tried the new ice formations, this glow looked different. And we all looked at it for a while and then said, ‘This is new, right? Is this definitely a different glow?’ So we showed a spectrometer on it, and each type of ice spectrum was different. “

To study the mockup of the Europa surface laboratory, the JPL team created a unique tool called the Ice Chamber for Europa’s High-Energy Electron and Radiation Environment Testing (ICE – Heart). They took the ICE-heart to a high-electron electron beam facility in Gathersburg, Maryland, and began experiments with a completely different study in mind: to see how the organic matter under Europa ice would react to an explosion of radiation.

They do not expect to see variations in the glow associated with different ice formations. Those writers called it Serendipity.

Seeing the sodium chloride brine at a significantly lower level of glow was an ‘aha’ moment that changed the course of research, ”said Fred Batman, co-author of the paper, who co-authored the paper. Delivered radiation beams to ice samples at the Medical Industrial Industrial Radiation Facility at Standards & Technology.

The moon appearing in the dark sky does not seem unusual; We see our own moon because it reflects sunlight. But Europe’s glow is caused by a completely different mechanism, scientists said. Imagine a moon that is constantly glowing, even on the edge of its night – that side faces away from the sun.

“If Europa weren’t below this radiation, it would make our moon look the way we do – dark next to the shadows,” Gudipati said. “But because it is bombarded by Jupiter’s radiation, it glows in the dark.”

Ready to launch in the mid-2020s, NASA’s next flagship mission, the Europa Clipper, will observe the lunar surface in several flyovers while orbiting Jupiter. Mission scientists are reviewing the authors’ findings to assess whether glow can be detected by spacecraft’s science tools. It is possible that the information collected by the spacecraft could be used to identify the salt components on the lunar surface or to shorten what they might be, with new research measures.

“It doesn’t often happen that you’re in the lab and say, ‘We can get this when we get there,'” Gudipati said. “Usually this is the other way around – you go there and find something and try to explain it in the lab. But our prediction goes back to a simple observation, and that’s about science. “

Missions like Europa Clipper help to contribute to the field of astrology, interdisciplinary research on the variables and conditions of the distant world that we know can capture life. While the Europa Clipper is not on a mission to find life, it will carry out detailed espionage operations in Europe and investigate whether the icy moon, along with its subsurface sea, has the ability to support life. Understanding the European habitat will help scientists better understand how life evolved on Earth and the possibility of finding life beyond our planet.