The Milky Way may face a cosmic collision in about two billion years which is relatively soon at the scale of the universe.
Astrophysicists at Durham University, UK, predict that the Large Magellanic Cloud (LMC) could hit the Milky Way in two billion years’ time.
The satellite galaxy is hurtling towards us and could fling out Solar System out into the depths of space, scientists have said.
There are several reasons that make our galaxy unique among normal spiral galaxies. For its size, its central black hole seems to be an order of magnitude too small; its stellar halo has far fewer heavy elements than other spiral galaxies; and its biggest satellite galaxy, the Large Magellanic Cloud (LMC), is unusually large.
So, a new simulation suggests the collision could occur much earlier than the predicted impact between the Milky Way and Andromeda, which may hit our galaxy in eight billion years.
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The findings are published today (Friday, 4 January) in the journal Monthly Notices of the Royal Astronomical Society.
What Could Happen?
Scientists have predicted that such a collision could cause destruction throughout our galactic neighborhood. It 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.
As it feeds, the now-active black hole would throw out high-energy radiation and while these cosmic fireworks are unlikely to affect life on Earth, the scientists say there is a small chance that the initial collision could send our Solar System hurtling into space.
The LMC will also bring heavy elements into the stellar halo.
“Many of the apparent ‘unusual’ properties of the Milky Way are temporary,” says team member Alis Deason. “After the collision with the LMC, the Milky Way will look much more typical.”
However, this doesn’t necessarily mean Earth is in danger. Luckily, because there is so much space between the stars in galaxies, everything will probably be okay for us.
The Large Magellanic Cloud
The Large Magellanic Cloud is the brightest satellite galaxy of the Milky Way. It only entered our neighborhood about 1.5 billion years ago and sits about 163,000 light years from the Milky Way.
Until recently astronomers thought that it would either orbit the Milky Way for many billions of years or, since it moves so fast, escape from our galaxy’s gravitational pull.
But recent measurements indicate that the Large Magellanic Cloud has nearly twice as much dark matter than previously thought. The researchers say that since it has a larger than expected mass, the Large Magellanic Cloud is rapidly losing energy and is doomed to collide with our galaxy.
Thumbnail image: The Whirlpool Galaxy (M51a) and companion galaxy (M51b). This Hubble Space Telescope image represents a merger between two galaxies similar in mass to the Milky Way and the Large Magellanic Cloud. Credit: NASA, ESA, S. Beckwith (STScI), and The Hubble Heritage Team (STScI/AURA)