Nearby galaxy is hurtling towards Milky Way on collision course which could wipe out life on Earth

Sarah Knapton

 

A neighbouring galaxy is hurtling towards the Milky Way on a collision course which could shift Earth outside the Goldilocks zone, making it too hot or too cold for life, scientists have warned.

New research led by astrophysicists at Durham University, predicts that the Large Magellanic Cloud (LMC) could hit the Milky Way in two billion years’ time.

Although the collision will not directly impact the Solar System, it will trigger a secondary chain of events, dislodging other stars from their around our galaxy and increasing the chance of entering new gravitational fields which could change the orbit of planets.

Although the crash is a long way off, it could end life on Earth two billion years sooner than expected.

Currently scientists expect changes in the Sun to cause a runaway greenhouse effect around four billion years from now which would melt the surface and kill any remaining life.

Lead author Dr Marius Cautun, a postdoctoral fellow in Durham University’s Institute for Computational Cosmology, said: “Any such change is very dangerous for life, since even small variations in the distance between the Earth and the Sun can move our planet outside the Goldilocks zone and make it either too hot or too cold for life.

“While two billion years is an extremely long time compared to a human lifetime, it is a very short time on cosmic timescales.”

The Large Magellanic Cloud is the brightest satellite galaxy of the Milky Way and only entered the neighbourhood about 1.5 billion years ago.

It currently sits about 163,000 light years from the Milky Way and until recently astronomers thought that it would either orbit the Milky Way for many billions of years, or, escape from our galaxy’s gravitational pull.

However, recent measurements indicate that the Large Magellanic Cloud has nearly twice as much dark matter than previously thought meaning it is doomed to collide with our galaxy.

The black hole at the centre of the Milky Way could increase tenfold, flinging the Solar System out into intergalactic space  Credit: Barcroft Media 

The catastrophic collision could also wake up our galaxy’s dormant black hole, which would begin devouring surrounding gas and increase in size by up to ten times.

And the black hole would throw out high-energy radiation which could fling the Solar System outside of the Milky Way in intergalactic space, devoid of stars.

“We don't fully know how this will affect life on Earth, but we can make a few predictions,” added Dr Cautun.

“Our descendants will see a very different night sky, much darker than currently with only a small bright patch that will correspond to the Milky Way galaxy.

“Furthermore, it will be tremendously more difficult for our descendants to travel to other stars. Currently, the nearest star is four light years away.

“However, if our Solar System would be outside the Milky Way, the nearest star would be hundreds or even thousands of light years away.”  

Co-author Professor Carlos Frenk, Director of the Institute for Computational Cosmology, Durham University, added: “Barring any disasters, like a major disturbance to the Solar System, our descendants, if any, are in for a treat: a spectacular display of cosmic fireworks as the newly awakened supermassive black hole at the centre of our galaxy reacts by emitting jets of extremely bright energetic radiation.”

The findings are published in the journal Monthly Notices of the Royal Astronomical Society.