Scientists have observed light shows on Venus for many years and during that time, the most accepted explanation was lightning. Venus might even have more lightning than Earth, NASA said in a statement from 2007.
But a new study is forcing scientists to rethink those preconceived notions, suggesting that Venus' mysterious flashing lights are actually meteors burning up in the planet's atmosphere.
The study, published in the Journal of Geophysical Research: Planets, notes that lightning on Venus is "either ubiquitous, rare, or non-existent, depending on how one interprets diverse observations."
One reason the researchers don't think it's lightning is because of Venus' radio silence.
On Earth, one way the National Severe Storms Laboratory monitors storms is by detecting radio waves from lightning. But, in the past, the Cassini Probe and Parker Solar Probe investigated the "lightning" on Venus while flying by the planet, and neither detected radio signals.
Figuring out the flashes are probably meteors, however, took additional research.
Scientists at Arizona State University counted the number of flashes observed at both the Steward Observatory and Japan's Akatsuki orbiter. They estimated between 10,000 and 100,000 flashes per year, which aligned with potential meteor strikes — enough to lead the researchers to conclude that meteors may be the culprit, according to Phys.org.
Venus also has sulfuric acid clouds instead of water vapor, which may not even be capable of producing lightning. These factors could indicate that the frequent flashes aren't lightning at all.
That's good news for future missions to Venus; if the flashes were lightning, it could pose a threat to probes entering the planet's atmosphere, according to NASA.
"Lightning is likely too rare to pose a hazard to missions that pass through or dwell in the clouds of Venus," the study said. "Likewise, small meteoroids burn up at altitudes of ∼100 km, roughly twice as high above the surface as the clouds, and also would not pose a hazard."
Researchers believe that probes that descend quickly through Venus' atmosphere are likely safe, Space.com reported.
A spacecraft hasn't landed on Venus since the 1980s. Extreme heat and crushing pressure make it very inhospitable. The Soviet Union's Venera 13 probe set the record for surviving two hours on the planet in 1981.
NASA plans to send the DAVINCI probe to study Venus' clouds and geology in 2031 and hopefully retrieve other data when its atmospheric descent probe makes contact with the surface.
