Scientists have just found something extraordinary ont he surface of Titan, Saturn’s largest moon and the subject of significant study by NASA: huge canyons filled with liquid methane. Whereas it is water on Earth that erodes the rock to create our amazing canyons, liquid methane on Titan has been doing the same thing to that frigid, rocky moon, as it turns out.

Scientists called the discovery remarkable, especially in how similar it is to the erosion process on Earth. Using data from Cassini, scientists were able to demonstrate that some of these canyons are as deep as 2,000 feet, according to a NASA statement.

Titan is already known to have huge oceans of liquid methane, but this is the first evidence scientists have seen of liquid-filled channels. Titan has often been called the most Earth-like world ever found due to its atmophere and lakes and rivers, but its extreme cold temperatures makes it impossible for liquid water to exist.

Methane, however, can survive as a liquid on Titan’s surface, and would actually boil away if it were just a tiny bit warmer on the moon.

Scientists were able to spot these methane-filled canyons by finding areas darker than the higher surfaces around them. However, they weren’t sure if it was darker due to shadows or from methane, so they bounced radio signals off the surface, allowing them to determine that methane is the most likely cause of their shapes.

“It’s likely that a combination of these forces contributed to the formation of the deep canyons, but at present it’s not clear to what degree each was involved. What is clear is that any description of Titan’s geological evolution needs to be able to explain how the canyons got there,” said Valerio Poggiali of the University of Rome, a Cassini radar team associate and lead author of the study.