The end of the world might not be something we enjoy thinking about, but a new study has provided a terrifying glimpse at what could be in store.
Astronomers say there’s a 50 per cent chance the Andromeda galaxy – also known as Messier 31 – will collide with the Milky Way in the next 10 billion years, swallowing Earth in the process.
While this sounds like bad news, a 50/50 chance is actually less certain than scientists previously assumed.
If and when the collision occurs, planets and stars in the two galaxies would be flung together, creating one super galaxy known as ‘Milkdromeda’.
There’s a small chance our sun would collide with another star, which could alter our position in relation to the sun and threaten life on Earth – if it still exists by then.
This illustration shows a stage in the predicted merger between our Milky Way galaxy and the neighboring Andromeda galaxy, as it will unfold over the next several billion years. In this image, representing Earth’s night sky in 3.75 billion years, Andromeda (left) fills the field of view and begins to distort the Milky Way with tidal pull
The new study is authored by an international group of astronomers, including professors Alis Deason and Carlos S. Frenk at Durham University.
‘It is commonly believed that our own Milky Way is on a collision course with the neighboring galaxy… predicted in around five billion years,’ they say in their paper.
‘(But there’s) no certainty of a Milky Way-Andromeda collision.’
At 2.5 million light years away, Andromeda is the closest large galaxy to our galaxy, the Milky Way.
Astronomers have long known that Andromeda and the Milky Way are being drawn together by the forces of gravity.
They are expected to come together in about 4.5 billion years and form a giant ‘elliptical galaxy’ – shaped like a stretched circle, NASA says.
But according to the authors of the new study, the nature of the merger may depend on an overlooked ‘confounding factor’.
Specifically, there may be a strong gravitational influence of other galaxies in what’s known as the ‘Local Group’ that could affect their direction.
The Local Group is a group of more than 30 galaxies to which both the Milky Way and Andromeda belong.
Other galaxies in the ‘local group’ include the Large Magellanic Cloud (LMC), Triangulum Galaxy (M33), Leo I, and NGC 6822.
Present day view of Andromeda and the Milky Way galaxy. Astronomers have long known that Andromeda and the Milky Way are being drawn together by the forces of gravity
NASA says that 7 billion years from now, the two galaxies will have combined and formed a huge elliptical galaxy (artist’s impression)
Using observations conducted by the Gaia and Hubble space telescopes, the researchers estimated future scenarios in the evolution of the Local Group over the next 10 billion years.
‘We find that the next most massive Local Group member galaxies – namely, M33 and the Large Magellanic Cloud – distinctly and radically affect the Milky Way-Andromeda orbit,’ they report.
‘Uncertainties in the present positions, motions and masses of all galaxies leave room for drastically different outcomes.’
There’s a probability of ‘close to 50 per cent’ that there is no Milky Way-Andromeda merger within the next 10 billion years, they conclude.
The Andromeda Galaxy is approximately 2.5 million light-years from Earth and the nearest large galaxy to our galaxy, the Milky Way
If the collision does occur, there is of course the chance of it happening after our sun has run out of hydrogen and died.
In the very unlikely event of the Milky Way-Andromeda collision happening while Earthlings are still alive on Earth, we could just survive it.
According to NASA, the sun and its orbiting planets will ‘survive the crash but take on new coordinates in the cosmos’.
Eric Bell, professor of astronomy at the University of Michigan who wasn’t involved in the new study, agreed ‘very likely nothing’ will happen to us in the event of the galaxy collision.
As the merger occurs, it’s likely the sun will be flung into a new region of our galaxy, but Earth and the rest of the solar system won’t be in danger of being destroyed.
However, one potential danger of a galaxy merger would be a collision (or near collision) between our star with another star, although there’s an extremely small chance that would happen.
‘Galaxy collisions would only be dangerous because of a slightly increased chance of star collisions,’ Professor Bell told MailOnline.
Even a near collision with another star – a ‘close pass’ – would affect our orbit, which Professor Bell said would be ‘very bad’.
‘The close pass changes the orbit, bringing us closer to the sun, or bringing us further away,’ he said.
‘What our fate would be depends on exactly how our orbit changed.
‘So we would either escape the solar system (in which case we’d slowly freeze to death over months), or get cooked by the sun (which may be very fast, or take months, depending on the orbit we ended up in) .’
The new study has been released as a pre-print on the arXiv server, meaning it’s yet to be peer-reviewed.