More news from this year’s slightly apocalyptic AAS: a giant cloud of gas is speeding towards the Milky Way at 150 miles per second. It’s going to hit in 20 million to 40 million years so your children’s, children’s, children’s … [repeat 800,000-odd times] … children could get to witness a spectacular display.

Our reporter at the conference, Alex Witze, has the low down:

Scientists have known about the cloud since 1963, when astronomer Gail Smith identified it before dropping out of research. At the time, no one knew whether the cloud was headed for us, away from us, or something in between.

New observations from the Green Bank radiotelescope – the big dish in the West Virginia mountains that’s surrounded by a zone of cellphone silence, so as not to interfere with the telescope – have pinned down the cloud’s trajectory.

The cloud is called Smith’s Cloud, after its discoverer. “This is most likely a gas cloud left over from the formation of the Milky Way or gas stripped from a neighbour galaxy. When it hits, it could set off a tremendous burst of star formation. Many of those stars will be very massive, rushing through their lives quickly and exploding as supernovae. Over a few million years, it’ll look like a celestial New Year’s celebration, with huge firecrackers going off in that region of the Galaxy,” says Felix Lockman, of the National Radio Astronomy Observatory (press release).

My boss the SF fan says he thinks this is part of the scenario behind Alastair Reynold’s Revelation Space books

Image: Green Bank Telescope image of Smith’s Cloud, which is headed toward a collision with the Milky Way / Bill Saxton, NRAO/AUI/NSF