Destination Uranus
In 1986, thanks to the Voyager 2 space probe, NASA managed to approach Uranus for the first time. It’s the coldest planet in our solar system, although not the farthest from the sun. This phenomenon, as scientists discovered, is due to the fact that it does not have an internal heat source. Also, there was evidence of a boiling ocean below the cloud tops.
Explained almost 3 years ago:
https://earthsky.org/space/wow-signal-explained-comets-antonio-paris