Washington - Don't worry about when the world as we know it might end. Nasa has calculated that our entire Milky Way galaxy will crash into a neighbouring galaxy with a head-on hit - in four billion years.
Astronomers in a Nasa news conference on Thursday announced that observations from the Hubble Space Telescope detail a long-anticipated galactic smash-up.
Astronomers had seen the Andromeda galaxy coming at us, but thought there was a chance that its sideways motion would make it miss or graze the Milky Way. Hubble readings say there's no chance of that.
Scientists say the sun and Earth should easily survive what will be a 1.9 million kilometres per hour galactic merger, but likely will be in a different place in the cosmos.