MARS * U.A.E. LIGHTS : SCIENCE ESSAY

 

AURORAS color the red planet skies. You don't have to go north : The U.A.E.'s Hope orbiter found them at all latitudes.

When barrages of charged protons and electrons erupt from the sun and 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 the Northern Hemisphere's polar regions, and the aurora australis in the Southern.

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

The Hope spacecraft, launched by the United Arab Emirates and orbiting Mars since February, has captured images of these dancing atmospheric lights, known as discrete auroras. Officials released the pictures last month.

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

The glows on Mars are not just at the top and bottom of the planet because the magnetic field around the planet has largely died out, as molten iron in the interior has 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 and 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 and dumped them into the crust of the planet,'' said Dr. Deighan, a researcher at the University of Colorado's Laboratory for Atmospheric and Space Physics, which is collaborating with the U.A.E. '' 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 and 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 of the night side of Mars.

Taking pictures of auroras was not among the core science observations planned for the Hope spacecraft. The mission is studying 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 was launched, scientists realized that one of the instruments, which makes observations in the far-ultraviolet part of the spectrum to measure levels of oxygen any 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.

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

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

The World Students Society thanks author Kenneth Chang.