One of the more unique features of Earth, at least as far as current space exploration has been able to show us, is a “hydrologic system,” or a stable system of liquid transformation from solid to liquid to gas and vapour. On Earth, this system is one made up of water, where precipitation forms rivers, which flow into seas and oceans, and then evaporate back into a gaseous state to restart the whole system over again.
We do however have one very close neighbor which shares a similar feature. Jupiter’s moon Titan, a cold world distant from our sun, has a hydrologic system made of methane.
NASA JPL has released a photograph of a “mini Nile” which empties into a smallish a sea called the Kraken Mare, about the size of the Caspian here on Earth. Like the Nile, it is formed of a large number of tributaries feeding into one relatively straight river basin. Scientists speculate that the straightness of the main column may suggest that the river actually marks a fault line in the bedrock of the moon. Whether this indicates some sort of tectonic plate, as it might on Earth, remains a mystery.
Whereas the Nile river is some 4,100 miles long, this newly-photographed river is a scant 200 miles. But the similarities between the features of these two worlds are striking. This also represents the first time an active river has ever been photographed at this resolution outside of our Earth system.