Scientists Stumped by Mysterious Flashes of Light on Venus

If they aren't flashes of lightning, what could they be?

Greased Lightning

Mysterious flashing lights on Venus that scientists initially thought were from lightning, may be something else entirely.

As detailed in a study published in the Journal of Geophysical Research: Planets, researchers out of Arizona State University have suggested that flashes of light detected during missions to Venus may not be lightning strikes, as some scientists have posited, but instead could be tens of thousands of meteors burning up in its ultra-hot atmosphere.

Missions conducted by Europe, the US, and the former Soviet Union all detected signals believed to be lightning. Subsequent missions like NASA's Cassini probe, however, "searched for but failed to find radio signals from lightning," according to the new paper, which left scientists stumped.

Although "artists depicting the atmosphere of Venus love to include lightning bolts to emphasize its hellish environment," it seems unlikely, the ASU scientists contend, that lightning is the culprit behind the strange light observations coming from the planet.

That's because, among other reasons, its clouds are made up almost entirely of sulfuric acid rather than water vapor — a necessary ingredient for lightning to form at least here on Earth.

Instead, those signals may indicate that meteors are burning up in the planet's "hellish" atmosphere, a finding that underlines how little we know about the mysterious rocky giant.

Meteor Madness

Using data from the University of Arizona's Steward Observatory and Japan's Akatsuki Venus orbiter, the team found that there were between 10,000 and 100,000 flashes recorded per year that could correspond to meteor fireball. While that number seems awfully high by Earth standards, the researchers noted that there would be far more meteors approaching Venus' atmosphere than our own because it's closer to the Sun.

The researchers went on to predict that the makeup of the planet's atmosphere could be why the fireballs burn bright enough for them to be detected.

If Venus's mysterious flashes are the result of meteor fireballs, scientists won't need to worry about building lightning-proof balloons to probe the planet's atmosphere — though of course, there could still be volcanic lightning on its surface, the researchers note, complicating an already hellish mission.

Updated to correct an error about which university runs Steward Observatory.

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