Is there lightning on Mars? New evidence suggests it’s there, just hard to see

NASA discovers new signs of lightning on Mars

By Meghan Bartels edited by Lee Billings

Lightning long ago escaped the confines of Earth’s atmosphere – scientists have already spotted lightning blazing through the skies of Jupiter, Saturn and Neptune. Now they think they have found it on Mars too.

But actually detecting lightning on the Red Planet has been challenging. Earth’s lightning is so striking because of our world’s thick atmosphere and strong magnetic field. In comparison, Mars has only a thin atmosphere and small patches of a small magnetic field. On the latter planet, scientists have hypothesized, lighting would not be dramatic arcs erupting overhead, but more like glowing sparks set off by electrostatically charged dust swirling through the sky.

“We cannot describe it as lightning from Earth, but the principle is similar,” says Ondřej Santolík, a space physicist at the Czech Academy of Sciences. “It’s kind of hard to guess what it looks like because no one has taken a picture yet.”

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Santolík is one of the researchers behind the new research, published on 27 February i The progress of science, which has announced possible evidence of a lightning strike on Mars, an event that occurred in June 2015 and whose signature was detected in data collected by NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) mission. The paper comes just months after other researchers published a very different kind of evidence for Martian lightning based on data collected by a microphone on NASA’s Perseverance rover.

“It kind of gives the feeling that we’re getting closer to Martian lightning,” said Karen Aplin, a space physicist at the University of Bristol in England, who researches lightning but was not involved in either study.

Confirming the presence of lightning on Mars is not just a matter of scientific curiosity, notes Aplin. Any form of lightning can threaten space technology, and lightning has also been shown to trigger chemistry that can contribute to the development of life.

MAVEN is an orbiter mission, so it offers a long-range view of Martian lightning. In their work, Santolík and his colleagues looked for a phenomenon called whistlers. When lightning strikes, it heats and ionizes the surrounding air, which can act as a natural antenna to blast lightning-generated radio waves through and out of a planet’s atmosphere. These waves are picked up on a receiver and have a whistle-like tone, hence the name.

In all, the team reviewed 108,418 snapshots from MAVEN in search of Martian whistles, a daunting task. “This has to be done visually because it is very difficult to do it with a machine because of the noise features in the data,” Santolík says. In the end, the researchers found only one candidate. “It’s very surprising that we found it at all,” Santolík says. The researchers spent a year confirming that the observation matched what they could expect from lightning.

Whether any similar observations will be available in the future is unclear because NASA has been out of contact with MAVEN for nearly three months now.

Meanwhile, the recent paper based on Perseverance data found dozens of examples of crackling sounds produced by tiny electrical discharges during dust storms near the rover. These observations are not contradictory, but probably do not represent completely identical phenomena. That’s entirely plausible — Earth also has different types of electrical discharges, with the lightning from a thunderstorm being very different from the glow of Saint Elmo’s fire, notes Aplin.

For Santolík, as tantalizing as the observations are, they remain a poor consolation prize. He is a member of the team that built a specially designed lightning detector to fly on the Russian-made lander for the Rosalind Franklin Mars rover, a project led by the European Space Agency (ESA), which was once scheduled to launch in 2022. However, that plan changed when that international partnership dissolved just months before launch following Russia’s full-scale invasion of Ukraine.

ESA has been scrambling to build its own lander for the rover’s new launch date of 2028 – and to speed up construction, they chose not to install instruments on the platform. Santolík and his colleagues recently received their instrument back, but now don’t expect it to ever see the Red Planet, much less the world’s elusive lightning.

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