Nearby galaxy set to collide with Milky Way, say scientists
Source: The Guardian
Nearby galaxy set to collide with Milky Way, say scientists
Collision will ‘cause fireworks’ but probably won’t happen for about 2.5 billion years
Ian Sample Science editor
Fri 4 Jan 2019 00.01 GMT
As if battered post-Christmas finances, a looming disorderly Brexit and the prospect of a fresh nuclear arms race were not enough to dampen spirits, astronomers have declared that a nearby galaxy will slam into the Milky Way and could knock our solar system far into the cosmic void.
The unfortunate discovery was made after scientists ran computer simulations on the movement of the Large Magellanic Cloud (LMC), one of the many satellite galaxies that orbits the Milky Way. Rather than circling at a safe distance, or breaking free of the Milky Way’s gravitational pull, the researchers found the LMC is destined to clatter into the galaxy we call home.
At the moment, the LMC is estimated to be about 163,000 light years from the Milky Way and speeding away at 250 miles per second. But simulations by astrophysicists at Durham University show that the LMC will eventually slow down and turn back towards us, ultimately smashing into the Milky Way in about 2.5 billion years’ time.
While individual stars and planets are unlikely to collide, the arrival of a galaxy weighing as much as 250 billion suns will still wreak havoc. “The whole of the Milky Way will be shaken and the entire solar system could be ejected into outer space,” said Carlos Frenk, director of the Institute for Computational Cosmology at Durham. “If that happens, I don’t see how our descendants, if we have any, will be able to withstand it.”
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Read more: https://www.theguardian.com/science/2019/jan/04/nearby-galaxy-large-magellanic-cloud-set-to-collide-with-milky-way
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Source: Monthly Notices of the Royal Astronomical Society
The aftermath of the Great Collision between our Galaxy and the Large Magellanic Cloud
Marius Cautun Alis J Deason Carlos S Frenk Stuart McAlpine
Monthly Notices of the Royal Astronomical Society, Volume 483, Issue 2, 21 February 2019, Pages 2185–2196, https://doi.org/10.1093/mnras/sty3084
Published: 13 November 2018
ABSTRACT
The Milky Way (MW) offers a uniquely detailed view of galactic structure and is often regarded as a prototypical spiral galaxy. But recent observations indicate that the MW is atypical: it has an undersized supermassive black hole at its centre; it is surrounded by a very low mass, excessively metal-poor stellar halo; and it has an unusually large nearby satellite galaxy, the Large Magellanic Cloud (LMC). Here, we show that the LMC is on a collision course with the MW with which it will merge in 2.4+1.2−0.8Gyr (68 per cent confidence level). This catastrophic and long-overdue event will restore the MW to normality. Using the EAGLE galaxy formation simulation, we show that, as a result of the merger, the central supermassive black hole will increase in mass by up to a factor of 8. The Galactic stellar halo will undergo an equally impressive transformation, becoming 5 times more massive. The additional stars will come predominantly from the disrupted LMC, but a sizeable number will be ejected on to the halo from the stellar disc. The post-merger stellar halo will have the median metallicity of the LMC, [Fe/H] = −0.5 dex, which is typical of other galaxies of similar mass to the MW. At the end of this exceptional event, the MW will become a true benchmark for spiral galaxies, at least temporarily.
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Read more: https://academic.oup.com/mnras/article/483/2/2185/5181341
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