Video: Milky Way on collision course with foreign galaxy The encounter, which is predicted to happen four billion years from now, will transform our galaxy. The Sun is likely to be flung into a new region, although scientists predict our Earth and solar system are in no danger of being destroyed. The prediction is the result of painstaking Nasa Hubble Space Telescope measurements of the motion of Andromeda, which also is known as M31. The galaxy is now 2.5 million light-years away, but it is inexorably falling toward the Milky Way under the mutual pull of gravity between the two galaxies and the invisible dark matter that surrounds them both. "After nearly a century of speculation about the future destiny of Andromeda and our Milky Way, we at last have a clear picture of how events will unfold over the coming billions of years," said Sangmo Tony Sohn of the Space Telescope Science Institute (STScI) in Baltimore. Computer simulations derived from Hubble's data show that it will take an additional two billion years after the encounter for the interacting galaxies to completely merge under the tug of gravity and reshape into a single elliptical galaxy similar to the kind commonly seen in the local universe. Furthermore, M31's small companion, the Triangulum galaxy, M33, is expected to join in the collision and perhaps later merge with the M31/Milky Way pair. In this video, the scientists discuss their quest to determine the fate of the Milky Way galaxy and reflect on the encounter's possible influence on our solar system. Video courtesy: Nasa, ESA, M. Estacion, F. Summers, G. Bacon, B. Moster, J. Anderson, R. van der Marel, and S.T. Sohn (STScI)