Is THIS how the world will end? Scientists reveal the startling odds that the Milky Way will collide with the Andromeda galaxy – swallowing Earth in the process

Daily Mail​

4 days ago

From the death of the sun to a sudden asteroid impact, there are a number of terrifying ways the world could end.
Now, scientists have revealed just how likely one of those doomsday scenarios really is.
Researchers from Durham University have calculated the odds of the Milky Way colliding with the Andromeda galaxy, swallowing the Earth in the process.
Across 100,000 simulations, the researchers found that there is a 50/50 chance of our galaxy colliding with Andromeda within the next 10 billion years.
This collision - estimated to occur at a staggering speed of 220,000mph - would be 'devastating' for both galaxies, the experts warn.
Before you start to panic, the good news is that this probability is actually significantly lower than previous studies had suggested.
Co-author Professor Alis Deason, a computational cosmologist at Durham University, said: 'It used to appear destined to merge with Andromeda forming a colossal "Milkomeda".
'Now, there is a chance that we could avoid this fate entirely.'
The researchers say that the likely scenarios are that the galaxies pass by at over one million light-years apart (left) or they drift within 500,000 light-years (right) for a close pass
At 2.5 million light-years from Earth, the Andromeda Galaxy is the Milky Way's nearest major galaxy.
The large spiral galaxy measures 152,000 light-years from end to end and is believed to be roughly the same mass as the Milky Way.
But as the Milky Way and Andromeda drift through space, the gravitational pull of other nearby galaxies is pushing them dangerously close together.
As they pass in space, the galaxies' mutual gravitational attraction causes them to spiral ever closer together and, eventually, to merge.
Although galactic collisions are rare, light from very distant galaxies, which has been travelling since the early days of the Universe, gives us a hint of what this might look like.
Co-author Professor Carlos Frenk of Durham University, a cosmologist at Durham University, says: 'The Universe is a dynamic place, constantly evolving.
'We see external galaxies often colliding and merging with other galaxies, sometimes producing the equivalent of cosmic fireworks when gas, driven to the centre of the merger remnant, feeds a central black hole emitting an enormous amount of radiation, before irrevocably falling into the hole.'
Previous studies had suggested that the Milky Way and Andromeda would almost certainly suffer this fate in around five billion years' time.
If Andromeda (pictured from Earth) and the Milky Way merge after eight billion years, the Sun will likely have extinguished before this time
MAGELLANIC CLOUDS: SATELLITE GALAXIES FOR THE MILKY WAY
The Magellanic Clouds can be seen in the night sky with the naked eye and have been observed by ancient cultures for thousands of years.
The Large Magellanic Cloud is a relatively small 160,000 light years away from us, while the Small Magellanic Cloud is around 200,000 light years away.
They orbit the Milky Way once every 1,500 million years and each other once every 900 million years.
They were the closest known galaxies to the Milky Way until recently, when the Sagittarius and Canis Major dwarf galaxies were discovered and found to be even closer.
However, the researchers' new simulations now suggest that this might not be the way the world ends.
Professor Frenk says: 'Until now we thought this was the fate that awaited our Milky Way galaxy. We now know that there is a very good chance that we may avoid that scary destiny.'
In just two per cent of the 100,000 simulations, the Milky Way and Andromeda Galaxies collided within five billion years.
In around half of the simulations, the galaxies passed close enough to one another that they slowed, and began to spiral around into an eventual merger.
However, these collisions took place within eight to 10 billion years' time, rather than five billion.
This suggests that the collision between the two galaxies is not likely to mean the end of the world.
Lead author Dr Till Sawala, of the University of Helsinki, told MailOnline: 'Our results suggest that a collision, even if it happens, might take place after the Earth and the sun no longer exist.
'Even if it happens before that, it's very unlikely that something would happen to Earth in this case - even when two galaxies collide, collisions between stars are very unlikely.
Even if the Milky Way and Andromeda do merge before the sun dies, Earth will likely be unaffected since collisions between stars are so rare. Picture: a graph showing the simulated distances between the two galaxies
The researchers say their simulations yield a lower probability because they took more of the Milky Way's neighbouring galaxies into account, in particular the pull from a galaxy called the Large Magellanic Cloud.
Although this 'satellite galaxy' is relatively small, its pull is in the right direction to significantly impact the Milky Way's trajectory through space.
Including this factor in the simulations, makes it much less likely that the Milky Way will get close to Andromeda.
The bad news is that it is 'nearly certain' that the Milky Way will merge with the Large Magellanic Cloud in around two billion years.
'However, unlike the possible merger between the Milky Way and Andromeda, the merger with the Large Magellanic Cloud will be a so-called "minor merger" that will leave the Milky Way intact,' adds Dr Till.