Milky way to hit another galaxy in four billion years
Our galaxy is on a collision course with its nearest neighbour, Andromeda, and the head-on crash is expected in four billion years, the US space agency NASA said. Astronomers have long theorised that a clash of these galaxy titans was on the way, though it was unknown how severe it might be, or when. - But years of “extraordinarily precise observations” from NASA’s Hubble Space telescope tracking the motion of the Andromeda galaxy “remove any doubt that it is destined to collide and merge with the Milky Way,” NASA said in a statement. “It will take four billion years before the strike.” After the initial impact it will take another two billion years for them “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,” NASA added. The stars inside each galaxy are so far apart that they are not likely to collide with each other, but stars will likely be “thrown into different orbits around the new galactic center.” Scientists have long known that Andromeda, also known as M31, is moving toward the Milky Way at a speed of 4,02,000 kilometers per hour, or fast enough to travel from the Earth to the Moon in one hour. But the nature of the crash depended on the galaxy’s sideways motion in the sky, and that trajectory remained a mystery for more than 100 years until the latest analysis of Hubble’s findings were revealed.