Pons-Brooks, or "12P", is a shortish-period comet which Daniel Kirkwood calculated had got diverted - by Neptune - AD 991ish. Carl Sagan made it famous by not reading Kirkwood and claiming it had something to do with Chinese history - which it did not. It got to aphelion again last year although I wasn't paying attention.
Nature Astronomy was paying attention. So now 12P is famous again: its water is Earthlike. Of course it didn't contribute any water to us; the comet is still out there. But it formed with other comets as reached the inner solar system.
No comments:
Post a Comment