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 neighboring galaxy with a direct head-on hit — in 4 billion years.
Astronomers said at a NASA news conference Thursday that years of observations from the Hubble Space Telescope provide grisly details of a long-anticipated galactic smashup. Astronomers had seen the Andromeda galaxy coming at us, but thought there was a chance its sideways motion would make it miss or graze the Milky Way. Hubble readings now indicate that's not the case.
"This is pretty violent as things go in the universe," said Roeland van der Marel, an astronomer with the Space Telescope Science Institute in Baltimore that operates Hubble. "It's like a bad car crash in galaxy-land."
Scientists say the sun and Earth are unlikely to be hit by stars or planets from Andromeda because of the vast emptiness of the two galaxies. So Earth should easily survive what will be a 1.2 million-mph galactic merger. Even at that speed, the event would take about 2 billion years.
Once it's over, our solar system would be in a different place in the cosmos. The collision would dramatically change the view of the nighttime sky from Earth with Andromeda suddenly dominating.