Does lightning strike on Venus? Maybe not, study suggests

Venus could also be a (barely) gentler place than some scientists give it credit score for.

In new analysis, space physicists at CU Boulder have jumped right into a surprisingly long-running debate in solar system science: Does lightning strike on the second planet from the sun?

The group’s outcomes add robust new proof suggesting that, no, you most likely would not see bolts of lightning flashing from Venus’ thick, acidic clouds—or, no less than, not fairly often.

“There’s been debate about lightning on Venus for near 40 years,” mentioned Harriet George, lead creator of the brand new examine and a postdoctoral researcher on the Laboratory for Atmospheric and Area Physics (LASP). “Hopefully, with our newly out there knowledge, we will help to reconcile that debate.”

She and her group printed their findings within the journal Geophysical Analysis Letters.

The analysis takes a deep dive into one of the mysterious, and inhospitable, our bodies within the solar system. Venus is about the identical measurement as Earth, however its dense, carbon dioxide-rich ambiance has led to a runaway greenhouse impact. Anybody standing on the bottom would face searing temperatures of 900 levels Fahrenheit and crushing atmospheric pressures. No spacecraft has ever survived for various hours on the planet’s floor.

To discover this excessive world, the researchers turned to a scientific device that wasn’t designed to review Venus in any respect: NASA’s Parker Photo voltaic Probe, which launched in 2018 as a part of a 7-year mission to research the physics of the sun’s corona, or outermost ambiance, and the solar wind. Parker Photo voltaic Probe was designed, constructed and is now operated by the Johns Hopkins Utilized Physics Laboratory, which leads the mission for NASA.

In February 2021, the spacecraft swooped round Venus at a distance of roughly 1,500 miles. Within the course of, its devices picked up dozens of what scientists name “whistler waves”—pulses of power that, on Earth no less than, may be kicked off by bolts of lightning. The group’s knowledge confirmed that Venus’ whistler waves could not really originate from lightning, however fairly from disturbances within the weak magnetic fields that envelop the planet.

The outcomes agree with a 2021 study, which didn’t detect radio waves generated by lightning strikes coming from Venus. The analysis was led by Marc Pulupa of the College of California, Berkeley.

David Malaspina, a co-author of the brand new examine, mentioned the findings present simply how little people learn about one in every of our nearest neighbors.

“It’s totally uncommon that new scientific devices make it to Venus,” mentioned Malaspina, assistant professor at LASP and the Division of Astrophysical and Planetary Sciences. “We do not get lots of probabilities to do this type of fascinating analysis.”

Darkish and stormy nights

A lot of the controversy round Venus and lightning dates again to 1978 when a NASA spacecraft known as Pioneer Venus entered into orbit round Earth’s hotter, angrier twin. Virtually instantly, the spacecraft started choosing up the indicators of whistler waves tons of of miles above the planet’s floor.

For a lot of scientists, these indicators have been paying homage to a well-known phenomenon from Earth: lightning.

George defined that, on Earth, whistler waves are sometimes—however not at all times—created by lightning. Lightning strikes, she mentioned, can jostle electrons within the planet’s ambiance, which then launch waves that spiral out into space. These waves create whistling tones that early radio operators on Earth might hear utilizing headphones, therefore the identify “whistlers.”

If Venus’ whistler waves have an analogous origin, then the planet could be a monster of lightning, experiencing roughly seven occasions extra strikes than Earth. Scientists have additionally noticed lightning on Saturn and Jupiter.

“Some scientists noticed these signatures and mentioned, “That might be lightning,'” George mentioned. “Others have mentioned, “Truly, it might be one thing else.” There’s been backwards and forwards about it for many years since.”

A brush with Venus

Parker Photo voltaic Probe might supply scientists a possibility to resolve the controversy for good.

George mentioned that the spacecraft will skim by Venus seven occasions throughout its mission, utilizing these flybys to attract nearer and nearer to the sun. In 2021, throughout its fourth such maneuver, the probe obtained remarkably close to to the planet—passing into the shadow forged behind Venus, a main spot to go in search of whistler waves.

To seek out these indicators, George, Malaspina and their colleagues used Parker Photo voltaic Probe’s FIELDS Experiment, a set of electrical and magnetic area sensors that stand proud of the spacecraft. (A group at CU Boulder and LASP designed and constructed the Digital Fields Board, which analyzes indicators from the FIELDS sensors).

When the researchers analyzed a set of these whistlers, nonetheless, they seen one thing shocking: Venus’ whistler waves have been headed the flawed means. They gave the impression to be shifting down towards the planet, not out into space such as you’d count on from a lightning storm.

“They have been heading backward from what all people had been imagining for the final 40 years,” Malaspina mentioned.

What’s inflicting these backward whistlers is not clear. George and Malaspina suspect that they might emerge from a phenomenon known as magnetic reconnection—during which the twisting magnetic area strains that encompass Venus come aside then snap again along with explosive outcomes.

For now, the researchers say they should analyze extra whistlers to utterly rule out lightning as a trigger. They’re going to get their subsequent probability in November 2024 when the Parker Photo voltaic Probe makes its ultimate move by Venus, dropping all the way down to lower than 250 miles above the floor—brushing the highest of the planet’s “soupy” ambiance, Malaspina mentioned.

“Parker Photo voltaic Probe is a really succesful spacecraft. All over the place it goes, it finds one thing new.”