Oxygen molecules have to exist in space. Don't they? After all, oxygen is the tird-most abundant element in the universe, and it likes to form the O2 molecule. Astronomers always thought molecular oxygen was out there, but never found any.
Well, it was hiding, so it seems, in the constellation Orion, where the Herschel space telescope finally found it. Researchers presume free-floating molecular oxygen hasn't been spotted in quantity until now, because it's locked in solid particles of dust or in ice, but the whole thing is still very puzzling: there should be a lot more such oxygen than what we can put our fingers on. At least now we know it's not a pointless search.