[Hugo Böse]

Originally Posted by Ray Allan

Interesting composite photo--it is entirely possible for a Jupiter-size gas giant in another solar system to have an Earth-like moon if it is orbiting within the host star's habitable zone. A science fiction example would be in Star Wars where the Rebel base was on the oxygen-atmosphere moon Yavin shown orbiting a gas giant. The closest example of this in our solar system is Saturn's moon Titan which has a thick nitrogen atmosphere, but is in a deep-freeze given its location a billion miles from the Sun, far from the habitable zone.

Astronomers may have found a huge moon around a Jupiter-like exoplanet

....If the exomoon is real, it is about 2.6 times the size of Earth...

https://www.newscientist.com/article...ike-exoplanet/