NASA's Cassini spacecraft takes us on a guided tour of this mysterious lake on Titan.
Transcript:Titan is the only planetary body besides Earth that we know has lakes.
At 290 degrees Fahrenheit below zero, the only liquid that makes sense there is a combination of methane and ethane.
This lake is Ontario Lacus in Titan's southern hemisphere.
It's a little smaller than Lake Michigan.
We've colored the lake black because we think that's probably its real color, although we don't really know for sure.
We've exaggerated the heights of the shoreline features to make them easier to see.
Notice these hills? Probably made of water ice.
See how the liquid has flooded up the valleys?
Further north is a long, smoother beach that looks like it's been shaped by waves.
You can see some lines along the beach that might be old shorelines, like bathtub rings.
So we know the level of the lake has changed.
Now we're turning east to a very obvious bay that cuts into the beach, so it's likely to be younger.
We'll cross over the lake. You'll see some flooded valleys and in the background is a large river that makes a delta like the Mississippi river. Its shape means the lake is shallow and the river is slow.
Ontario's shore is surprisingly like Earthly lake shores.
Pretty amazing to find something this Earth-like, 800 million miles away.
NASA's Jet Propulsion Laboratory, California Institute of Technology