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Nearby dwarf galaxy will collide with Milky Way, awaken black hole at its heart

The Milky Way is under threat: new research from astrophysicists at Durham University, UK, suggests that the Large Magellanic Cloud (LMC) will dramatically collide with our galaxy in two billion years’ time.

It was previously predicted that the Milky Way would collide with the nearby galaxy of Andromeda in between four billion and eight billion years’ time, turning both galaxies into one combined giant elliptical galaxy. But now it seems that long before that collision happens, the Milky Way will be impacted by the LMC, the brightest satellite galaxy of the Milky Way which currently sits around 163,000 light-years from us.

The new prediction, published in Monthly Notices of the Royal Astronomical Society, was made once it was discovered that the LMC has nearly twice as much dark matter as previously believed, meaning that it has a much larger mass than was expected which affects the way that it interacts with other nearby galaxies. The increased mass means that the LMC is losing energy at a high rate and will inevitably collide with the Milky Way.

An image from the Hubble Space Telescope showing the merging of the Whirlpool Galaxy (M51a) and its companion galaxy (M51b), which are similar in mass to our Milky Way and the Large Magellanic Cloud. NASA, ESA, S. Beckwith (STScI), and The Hubble Heritage Team (STScI/AURA)

The effects of such a collision will be catastrophic: The meeting of the two galaxies could wake the dormant black hole at the heart of our galaxy, causing it to devour nearby gases and grow in size by up to ten times.

“The destruction of the Large Magellanic Cloud, as it is devoured by the Milky Way, will wreak havoc with our galaxy, waking up the black hole that lives at its center and turning our galaxy into an ‘active galactic nucleus’ or quasar,” lead author Dr. Marius Cautun, a postdoctoral fellow in Durham University’s Institute for Computational Cosmology, said in a statement. “This phenomenon will generate powerful jets of high energy radiation emanating from just outside the black hole. While this will not affect our Solar System, there is a small chance that we might not escape unscathed from the collision between the two galaxies which could knock us out of the Milky Way and into interstellar space.”

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