NEW: Japan’s ‘Dawn’ - the sole, lonely spacecraft orbiting Venus - has seen a mysterious flash in the planet’s exotic sky. What was it?

This signal *wasn’t* sent by aliens. But determining what caused has real implications for alien life.

Me, for @NatGeo https://www.nationalgeographic.com/science/2020/12/does-lightning-strike-on-venus-mysterious-flash-help-solve-puzzle/

The work, presented at @theAGU, has yet to be peer-reviewed, but this is an exciting result: we have been looking for lightning on Venus - a process which cools up all kinds of bespoke molecules, including prebiotic matter and perhaps even phosphine(!) - for about half a century.

Lightning can be found all over the solar system; the gas and ice giants have it in their cloudy skies. Venus has an unusual sulfuric acid atmosphere, but many expect lightning to exist in its cloudy shroud, albeit in a different way to how it exists on Earth.

Soooo where is it?

Previous possible detections of lightning, including whistle-like signals picked up by spacecraft to splotches of light seen from Earth, are vociferously debated. The community can’t all agree that any one signal is conclusive evidence of lightning.

Japan’s Akatsuki spacecraft was sent to Venus partly to try and look for the optical flash caused by lightning. And it’s found one - or what looks like one, anyway. It could also be an exploding meteor, but the odds of it seeing this during its short lifespan is unlikely.

For now, the best evidence is lightning.

Will it be the slam-dunk that convinces the scientific community that Venus definitely does have lightning? Hell no. But it’s arguably the best evidence yet.

But the only way to know for sure - the only way to understand anything about Earth’s evil twin - is not to peer from afar.

We have to go back. Or else we’ll be stumbling around in the dark, looking for the light - quite literally, in this case.

Cheers to @ThePlanetaryGuy, Noam Izenberg, @astrocurry, @karen_aplin, Ricky Hart and @PlanetaryColin for the end-of-year chats!