U.A.E.’s Mars Orbiter Gets New Views of Red Planet Auroras

When barrages of charged protons electrons erupted from the sun head our way, Earth’s magnetic field deftly deflects them around the planet. This buffeting generates shimmering, glowing curtains of color known as the aurora borealis in northern hemisphere’s polar regions, aurora australis in the south.

That same phenomenon happens on Mars, too. But there it is not just the northern lights southern lights, but also the equatorial lights, mid-latitude lights, eastern lights, western lights — all around the planet.

The Hope spacecraft launched by the United Arab Emirates orbiting the red planet since February, has captured unique images of these dancing atmospheric lights, known as discrete auroras.

Mission officials released the pictures on Wednesday.

“It will allow new doors of study to be opened when it comes to the Martian atmosphere,” said Hessa al-Matroushi, the science lead for the first interplanetary mission by the U.A.E., “how it interacts with the solar activity.”

The glows on Mars are not just at the top bottom of the planet, because the magnetic field around the planet has largely died out as molten iron in the interior cooled. But parts of the crust of Mars that hardened several billion years ago when Mars did have a global magnetic field preserve some of that magnetism.

“They’re very patchy unevenly distributed,” said Justin Deighan, the deputy science lead.

While Earth’s magnetic field is like one large bar magnet, on Mars, “it’s more like you took a bag of magnets dumped them into the crust of the planet,” said Dr. Deighan, a researcher at the University of Colorado’s Laboratory for Atmospheric Space Physics, which is collaborating with the U.A.E. on the mission. “And they’re all pointed different ways. And they have different strengths.”

The disjointed magnetic fields act as lenses to shepherd solar wind particles to different parts of the Martian atmosphere, but then they hit atoms molecules in the upper atmosphere, generating the glow of auroras.

Previous Mars orbiters have also observed the auroras, but Hope, with a high-altitude orbit that varies from 12,400 miles to 27,000 miles above the surface, can take in a global view of the night side of Mars.

Taking pictures of auroras was not part of the core science observations planned for the Hope spacecraft, which entered orbit around Mars in February. The mission is trying to study dynamics of the Martian atmosphere near the surface that influence how fast the atmosphere of Mars is leaking into space.

But even before the probe launched, scientists realized that one of the instruments, which makes observations in the far-ultraviolet part of the spectrum to measure levels of oxygen hydrogen in the upper atmosphere, might be able to pick out the auroras as well.

“Our guess was, we would see something, but we weren’t sure how often it was going to be,” Dr. Deighan said. “What’s really fantastic is that we basically saw it right away, with such clarity. It was unambiguous.”

NASA’s MAVEN spacecraft can also take similar pictures of the Martian auroras when its elliptical orbit takes it farther from the planet, it can also directly measure identify the solar particles creating the light show when it is passing close by. But it cannot make both measurements simultaneously.

By coordinating Hope’s aurora photographs with MAVEN’s particle measurements, planetary scientists might be able to put together a more complete understanding of the night lights of Mars.

“Having two spacecraft is really what you want for this,” Dr. Deighan said.

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