Milky Way and Andromeda will collide in the Future. How long will it take?
Astronomers predict Titanic Collision between Milky Way and Andromeda.
In about 4 billion years, two galaxies in the Local Group can produce a ‘galactic collision’. The Milky Way and Andromeda Galaxy are the most likely contenders in this regard. It’s a huge cosmic event as the entire solar system including the Sun and the Earth will be affected by it. Andromeda is traveling at a rapid pace of 250000 miles per hour towards our galaxy. Following this mega-clash, both the galaxies will change forever.
They will take two billion years to merge after their initial clash. This merger will mean that the cosmic location of our solar system will also change. A new elliptical galaxy will be formed which will replace the individual identities of both of these galaxies. About it, Sangmo Tony of the Space Telescope Science Institute said,
“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”.
Contrary to many other similar stories, it has nothing to do with fiction. In this era of science and technology, such events can be foreseen with good chances of getting an accurate result. This was the message that was to be transmitted to the general public through the third episode of ‘Cosmos: A Spacetime Odyssey’. Host Neil Tyson said,
“Using nothing more than Newton’s laws of gravitation, we astronomers can confidently predict that several billion years from now, our home galaxy, the Milky Way, will merge with our neighboring galaxy, Andromeda. Because the distances between the stars are so great compared to their sizes, few if any stars in either galaxy will actually collide. Any life on the worlds of that far-off future should be safe, but they will be treated to an amazing, billion-year-long light show.”
Many of you might be wondering, how on Earth do we know all this? The first practical step was taken by an astronomer called Vesto Slipher. He determined that Andromeda is moving swiftly towards us. The mechanism he adopted was to observe the stretching and compression of the light coming from that galaxy. The light coming from objects going away from us is a bit stretched and red-shifted whereas light from objects coming towards us is compressed and blue-shifted. Slipher reported his findings in the following words:
“We may conclude that the Andromeda Nebula is approaching the solar system with a velocity of about 300 kilometers per second.”
For decades, scientists had no method to determine whether these galaxies will smash into each other or not. Ultimately, the solution came through the measurements of Andromeda’s motion taken by the NASA Hubble Space Telescope. Proper motion, which is the speed of lateral movement, of Andromeda was calculated, in light of the images taken by this powerful telescope. Tony explained this procedure in the following words as he said,
“We compared images taken at different times with the Hubble Space Telescope and measured how much the Andromeda stars have moved relative to the fuzzy galaxies in the distant background. This gives us a sense of how fast the Andromeda stars moved across the sky.”
Despite the fact that these galaxies will strike into each other head-on, stars inside them will not collide as the distances among them are just too much. Having said that, the orbits of those stars will certainly change as our solar system will be tossed much away than it is today from the galactic core. Yet another exciting thing related to this galactic clash is the presence of Triangulum galaxy. It is also expected to take part in the collision and can also become a part of that merger. As this collision is beyond any doubt, let’s take a look at some interesting facts about it.
· The name proposed for this merged galaxy is “Milkomeda”.
· The Doppler Effect was used to calculate the speed of Andromeda. It uses the change in frequency and wavelength of the waves produced by an object moving away from an observer.
· When these two galaxies will collide, it will be an exhilarating light show for millions of years.
The space shuttles that are on missions to Hubble are upgraded and have more powerful cameras fixed in them so that more efficient data could be extracted from the motion of Andromeda.
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