Of all the alien worlds in our solar system, one
in particular resembles our home planet: Titan.
The largest moon of Saturn is the only other place we know of where
you could walk along the seashore or stand in the rain.
However, Titan's exotic seas and its oily raindrops are not made of water,
but of the natural gases methane and ethane superchilled into liquid form.
Now, NASA's Webb telescope has revealed
a crucial missing step in how ethane is formed,
and its discovery could tell us about the future of Titan's atmosphere.
Scientists used Webb's infrared camera to peer through the haze that envelops
Titan and spy methane rain clouds forming in its summer hemisphere.
Webb also detected
methyl, a fragment from methane’s breakup, in the upper atmosphere.
This confirms our suspicion that methane is being disintegrated, reforming
into heavier molecules like ethane, and raining back onto the surface.
Titan's rain cycle helps to keep its poles covered in lakes and seas,
but over time, the loss of methane could cause the moon to slowly dry up.
If the methane is not replenished by outgassing
from Titan's interior, then its lakes and seas, its rain clouds,
and even its haze could all disappear in the far future.
So who knows?
Perhaps one day our descendants will walk along a dry, dusty
seabed on Titan's surface, look up and see Saturn through a dark blue sky.