We’re all gonna die! A rogue cloud galaxy is coming and it’s going to smash into the Milky Way, make its black hole bigger and knock our planet out of the galaxy like a bocce ball!
Well, yes, yes, yes and possibly … although the people riding Earth as it hurdles through space will not be us. While astronomers have always known that galaxies can and do collide and the Milky Way is on a slow crash course towards Andromeda, new models have found a more immediate danger from something called the Large Magellanic Cloud which is headed our way much sooner than expected. How soon? Is it OK to spend the money you were planning to pass down to your grandkids?
“Ultimately, there is no escape.”
That would be a great opening line for “The Day Milky Way Met the Large Magellanic Cloud” but it’s actually the scary warning from Marius Cautun, an astrophysicist at Durham University’s Institute for Computational Cosmology and lead researcher on “The aftermath of the Great Collision between our Galaxy and the Large Magellanic Cloud,” a study published in the latest edition of the Monthly Notices of the Royal Astronomical Society. The Large Magellanic Cloud is a so-called ‘satellite’ galaxy, the second- or third-closest galaxy to the Milky Way and the fourth-largest galaxy in the Local Group – the group of 54 galaxies that includes the larger Andromeda, Milky Way and Triangulum galaxies. It’s visible as a faint cloud from the southern hemisphere between the constellations of Dorado and Mensa.
And it’s headed our way.
“The collision between our galaxy and the [Large Magellanic Cloud] takes place in the majority of cases—over 93 percent.”
Cautun led a team ran eight new supercomputer simulations using data from new observations that the Large Magellanic Cloud is much bigger than previously thought. While it’s currently headed away from the Milky Way, it is expected to turn around and head towards the black hole in its center and wreak havoc the likes of which the galaxy has not seen since the last collision, whenever that was. While that sounds pretty bad – it will cause the black hole to expand to five times its current size, spew jets of radiation, move stars around, knock planets out of orbit and possibly send solar systems out of the galaxy – Cantus, like a true astronomer with a rose-colored telescope, sees some good in the collision.
“This catastrophic and long-overdue event will restore the MW to normality.”
The “MW” (Milky Way) apparently has a small central black hole in comparison to other galaxies and this will give it a normal one. And how long will it be before MW can stop getting counseling to deal with its small black hole?
“Even though the LMC is currently heading away from the MW, dynamical friction acting on such a heavy galaxy will cause its orbit rapidly to lose energy and, approximately a billion years from now, to turn around and head towards the centre where it is destined to merge in another 1.5 billion years or so.”
That’s 2.5 billion years from now. If humans are still around, Cautun says the possibility that they will be knocked out of the galaxy is there but remote. More likely, they will witness a light show in the sky that will change the constellations considerably and get them ready for the bigger collision 2.5 billion years after that when Andromeda and the Milky Way begin to smash together with such force that only one will survive. If there are still bookies around, humans should put their money (or whatever they bet with in the year 5,000,000,002,019) on Andromeda.
If you’re smart, you’ll hide that last part from your grandkids as you spend their inheritance.