Hypervolcanic

One of the strangest places in the whole solar system is Jupiter's hypervolcanic Moon lo, which seems to be a little different every time we look at it.

Source: wiktionary

Josie opened a new browser window on her computer and ran a search for the Sixth Extinction. The top hit was a book by the same title. Next she browsed articles in Time magazine, USA Today, the New Yorker, the Guardian UK, and National Geographic. What made the Sixth Extinction different from the previous five ancient epoch-ending planetary die-offs was that this time the culprit was humankind. Not hypervolcanic activity. Not an asteroid from outer space. Not a glacial ice age. No, this time the instigator was man.

Source: wiktionary

Anybody wondering what Earth was like 4 billion years ago should cast an eye toward Jupiter's hypervolcanic moon Io, a new study suggests.

Source: wiktionary

We don't know if said planets even have an atmosphere (or one of reasonable density), if they get regularly bombarded by large asteroids, if they have liquid water, if they're truly temperate (runaway greenhouse effect ala Venus), if they're hypervolcanic, etc.

Source: wiktionary