The biggest observed galactic crash is under way, as four enormous collections of stars converge on each other. But, don’t worry about debris heading our way.
When the merger of the smaller galaxies is complete, the resulting galaxy will contain about 1 trillion stars, some 10 times the size of the Milky Way.
Unfortunately, none of us will ever see this happen. Although the galaxies are travelling at quite a clip, they are approaching each other much too slowly to see them move, said Kenneth J. Rines, who discovered the impending collision by accident while a postdoctoral astronomer at Yale University.

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(Details for astronomers inside kmz)