A new finding from the Rosetta spacecraft upsets a longstanding theory
A pair of sort-of comets pose a puzzle for astronomers
The difference between an asteroid and a comet was always thought fixed—but now a new paper says the two celestial bodies may be more similar than we thought
It's a comet! It's an asteroid! It's a bit of both—and it's one of the niftiest little members of the solar system
Chemistry plus heat can lead to biology—and cometary impacts warm things up nicely
Every comet that’s ever been spotted is a fugitive on the lam. Comets really have no business visiting the inner solar system at all. They don’t remotely...