Thanks to some new intel provided by NASA’s New Horizons probe, scientists now believe Pluto’s surface may have once hosted rivers and lakes of liquid nitrogen.
According to a report in New Scientist, the theory was developed by looking at data sent back by the probe, which aims to model how Pluto’s climate and atmosphere changed over time. Weather models are now pointing to different points in Pluto’s history at which the surface temperature would’ve been high enough for frozen nitrogen to melt on the surface (scientists believe Pluto already has frozen nitrogen). If true, that means the non-planet once hosted nitrogen lakes and rivers.
“Liquids may have existed on the surface of Pluto in the past,” mission leader Alan Stern said via New Scientist. “We see what for all the world looks to a lot of our team like a former lake. It’s very smooth, as if a liquid has frozen across one height. It’s hard to come up with an alternate model that would explain that morphology.”
Some of this interesting planetary layout is thanks to Pluto’s super-hard lean, which is on a 120-degree tilt (for the sake of comparison, Earth is on a 23-degree axis tilt). This wide tilt spreads the planet’s tropics across a wide swath of the planet. Of course, we’re still talking about Pluto (so it’s cold, regardless), but that tilt apparently provided enough variety to warm things up at some points in history.
The team estimates Pluto’s climate was probably warm enough for liquid nitrogen approximately 800,000 years ago, so if you get your time machine working, you know an era to plan the vacation.