Something appears to have smashed into Jupiter earlier this week, causing an explosion so big it could be seen by amateur astronomers on Earth.
The impact was caught on video by Ethan Chappell on Thursday afternoon (NZ time).
"Imaged Jupiter tonight,", the Texas-based amateur astronomer wrote on Twitter. "Looks awfully like an impact flash in the [southern equatorial belt]."
He didn't notice the impact at first, but when reviewing the video saw the brief flash.
"My mind started racing," he told website ScienceAlert. "I urgently felt the need to share it with people."
Pro astronomer Jonti Horner of the University of Southern Queensland told the site it was a "totally breathtaking" catch.
"To get a video like that, I've never seen anything like that before."
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At this stage, it's believed the intruder exploded somewhere in Jupiter's upper atmosphere. Initial reports said the explosion was as large as Earth, but Chappell said that's not clear yet.
"As of now, we don't have any estimates of how big the bolide or the flash was, but certainly much smaller than Earth," he wrote on Twitter, noting its size in comparison to the planet's famous great red spot.
Jupiter's strong gravity means it's likely to be hit by objects quite often, but catching them in the act is exceedingly rare. The most famous example was 1994's collision with comet Shoemaker-Levy 9. It broke apart, and for two years rained pieces down on the gas giant.
Heidi B Hammel - who led the team which studied Shoemaker-Levy 9's crash-course with Jupiter - congratulated Chappell on Twitter, but said it was unlikely the asteroid would leave a mark.