@badastro Thank you Phil. I keep hearing people say things like "If they go back and get a 5 sigma detection of DMS, that means they certainly found life on this planet," and I'm sitting here like no dude, that would mean they almost certainly detected DMS in the atmosphere of this planet, which is a compound we've seen in comets and interstellar dust -- we have no way of definitively saying it's life at all.

@badastro "K2-18b (note the lower-case “b”, denoting it’s a planet) is about 2.6 times the Earth’s diameter and 8.6 times its mass. Some people call it a super-Earth, but in my opinion that’s misleading; it’s more likely a mini-Neptune at that size and mass (so a small gas giant instead of gigantic rocky world)"

8.6x Earth mass with only 2.6x diameter is way too dense to be a gas giant.

Hm, I take that back. volume = 4/3 pi * r^3, 2.6x diam is 17.5x larger volume. Half density of earth, ok.