Will our Milky Way collide with Andromeda galaxy? What will happen if it happens? Astronomers at ESA say...

Will our Milky Way collide with the Andromeda galaxy that is hurtling towards us at the speed of 110 kilometres per second? If it happens, will the Milky Way be damaged and destroyed? Or will it simply touch with no devastating impact? Will this not happen at all and the Andromeda pass near our Milky Way? It was in 1912 that astronomers came to know about the possible collision for the first time. The astrophysicists at the Space Telescope Science Institute in Maryland, US declared that the galaxy is sure to collide with the Milky Way. Relax, don't get panicked. The collision may take place in four billion years.

What does ESA say?

However, the European Space Agency’s Gaia astrometric mission has said that the possibility of the collision is not as high as predicted earlier. The team of astrophysicists led by Till Sawala of the University of Helsinki, Finland revisited it, re-modelled the impending crash, and found that it’s 50/50 as to whether a collision happens or not.

Earlier in 2012, it was considered that the gravitational effect of an additional galaxy, the Large Magellanic Cloud (LMC), alongside the Milky Way, Andromeda and the nearby Triangulum spiral galaxy M33, may affect the path of collision. It was found that while M33’s gravity may add to Andromeda’s motion towards the Milky Way, the LMC’s gravity may pull the Milky Way out of Andromeda’s path.

What do astronomers say?

Talking to 'Physics World', Sawala said, "We’re not predicting that the merger is not going to happen within 10 billion years, we’re just saying that from the data we have now, we can’t be certain of it." Sawala and his team's research indicates that it may nevertheless be massive enough to turn a head-on collision into a near-miss. Sawala also said that the uncertainty with the greatest effect on merger probability lies in the so-called “proper motion” of Andromeda. This motion is a mixture of Andomeda’s radial motion towards the centre of the Milky Way and the two galaxies’ transverse motion perpendicular to one another.