Nasa reveals that Mars has its own northern lights and loses atmosphere with surprising speed, which could explain how the planet became dry

Mars has its own northern lights, a varied and changeable atmosphere and a history probably shaped by solar eruptions and magnetic “tendrils”, Nasa announced on Thursday, as it unveiled research that hinted at the fate of liquid water on the planet.



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Researchers with the Mars Atmosphere and Volatile Evolution (Maven) mission announced the findings of four studies, each published in the journal Science.

The Maven spacecraft entered Mars’s orbit last fall and has since dipped through the layers of the planet’s atmosphere and recorded what happens there when gas and magnetic energy explode off the sun and reach the red planet.

With only remnants left of the ancient magnetic field that once shielded the planet from solar winds as Earth’s still does, Mars is buffeted by solar blasts that create aurora lights across huge areas of the planet, the researchers found.

“We don’t know whether all the incredible curtains and waves of Earth’s aurora [would be] visible on Mars,” Nick Schneider, the study’s lead author and a professor at the University of Colorado at Boulder, told the Guardian. “But we ran the numbers and although most of the light comes out ultraviolet, you’ll get reds and blues and greens in carbon dioxide as you do in nitrogen and oxygen on Earth.”

Schneider said the Maven team “jokes about Matt Damon stranded on the surface of Mars”, a reference to the recent film The Martian. “If he was paying attention and there was a big solar storm he would’ve had a shot at seeing these aurora.”

The Martian aurora borealis dips 37 miles into the planet’s atmosphere, lower than any aurora found on any other planet. As on Earth, the rippling northern lights are caused by atmospheric particles excited by the electrons of the solar winds.

“Without much magnetic field at all, solar storms and wind just pummel Mars,” Schneider said. “Mars was clearly very warm and wet, with 100 times more atmosphere. So is it possible that all that atmosphere and an ocean’s worth of water went up?



“We’re not going to give the answer today, but this shows solar impact across vast swaths of Mars. It’s a huge step forward.”

The dramatic reaction of Mars’s surviving magnetic fields to the solar blasts may help explain how the watery world Mars was once became the dry one it is today. Mars’s magnetic fields reacted to the blasts by coiling into ropes stretching more than 3,000 miles into space, the researchers discovered. Ions gushed along the atmospheric ropes and into space as much as 10 times faster than usual.

“It’s astounding,” said Steve Bougher, a mission scientist and professor at the University of Michigan. “It’s the very first handle that we have on the role that these solar storms have on Mars’ upper atmosphere.

“If we can validate our models, the escape observations, run them back in time, we can start to see the big picture of what happened to water on Mars, and how Mars might’ve gotten the way it is today.”

Researchers believe solar storms were more frequent billions of years ago, when Mars still had lakes. The researchers did not measure exactly how much atmosphere – including more oxygen than expected – Mars lost during a blast in March this year, but they did note that past measurements have found escape rates 10 to 100 times greater than normal during solar storms.

A third study, led by Bougher, found that Mars has a varied and changeable atmosphere, with more oxygen than expected and what he called “wild variations” in temperature.

“These are the first measurements we’ve had in 40 years, since the Viking mission [which set off in 1975],” he said. “So while we only had two profiles, now we have a couple thousand.”

Bougher said that not only did solar winds strip away Mars’s atmosphere as expected, but gravity from the planet itself changed the atmosphere. Comparing gravity waves to ocean breakers crashing on a shoreline, he said such waves “propagate upward growing in amplitude, until they get too big, and break, changing the structure of the upper atmosphere”.

The process is similar to that on Earth, he said, although the team has been surprised by the magnitude of variation caused by the sun, the seasons and gravity waves. Mars’s gigantic mountains and canyons, far larger than anything on Earth, in part drive such forceful gravity waves.

“We’ve had some marvelous land missions on Mars, but now we’re seeing the other half of the story,” Bougher said. “We’ve been out playing in our sandboxes for a while. Now we can start to put the geologists, atmospheric, all the teams together.”

A fourth Maven team published on a new mystery hovering over Mars: dust more than 90 miles above the planet, well above the range any known process could lift it off the Martian surface.

Mars’s moons Phobos and Deimos could be the culprits, but the researchers noted that moon dust should have formed a “doughnut-shaped ring around the equator of Mars”. Over seven months, they did not observe any such ring.

The researchers suggest instead that the particles are actually interplanetary dust, the cosmic grains that drift off objects hurtling through space, including comets and asteroids, and which can be made up of the same materials that formed the solar system.

Interplanetary dust drifting into a planet’s atmosphere has only been observed on Earth, but the researchers argue that other clues, such as the dust’s range and flow, suggest Mars experiences the same phenomenon.