As seen from the Earth, the Milky Way looks like a long white stripe, luminous and diffuse. Since humanity exists, it is there, peaceful and unchanged. This situation is only calm before the storm.
Galaxies frequently collide with each other. Our Milky Way is no different and will hit its neighbor Andromeda in about 4 billion years. However, researchers have discovered that another threat will upset our galaxy well before this terrible impact.
New data, obtained by researchers at the University of Durham (New Window) , in England, show that the Large Magellanic Cloud, a dwarf galaxy on the outskirts of the Milky Way, will change course and hit us hard in a little over a billion years old.
The Milky Way will pass through this collision without much of the after-effects, but the upheavals we undergo will bring about profound changes, which will considerably change the view we have of the starry sky.
An unpredictable neighbor
Located 160,000 light-years away from the Milky Way, the Great Magellanic Cloud is the third closest galaxy to us, after the dwarf galaxies of Sagittarius and Great Dog.
It is said to be a dwarf galaxy, because it contains only thirty billion stars, a number much smaller than the hundreds of billions that are contained in conventional galaxies.
However, despite this number, recent observations have shown that the Great Magellanic Cloud is a more massive galaxy than previously estimated, a change that researchers explain by the fact that it has a large mass of dark matter.
This additional mass increases the effect of gravity between it and the Milky Way. According to the researchers’ calculations, although the Great Magellanic Cloud is now moving away from our galaxy, this force will slow our neighbor for hundreds of millions of years, until it makes her half turn, thus placing it directly in a path of fusion with the Milky Way, a billion years later.
A dazzling show
Although such impacts have the potential to radically transform the galaxies involved, these events are far from destructive.
These collisions make the resulting galaxies grow thanks to a supply of new stars. The turmoil and gravitational forces that shake the region also warm up gas clouds that collapse on themselves to create nurseries of stars.
According to the astrophysicists, if there is anyone left on Earth at that time, this person will be able to attend an amazing show!
While our galaxy will absorb its neighbor, a large amount of gas will flow directly to the supermassive black hole Sagittarius A, which hides in the center of the Milky Way. This input of material will make him take a size eight times larger than it currently has, in addition to generating a disk of superheated matter spinning towards the black hole. This phase of activity, called quasar, is one of the brightest phenomena in the universe.
There is usually no collision between the stars in these scenarios, because despite their considerable number, the distance between them is disproportionate.
However, the “brewing” suffered by the stars of the galaxy will eject several in the intergalactic vacuum. According to the researchers, there is a very slight probability that the Sun is among the unlucky ones. However, this is a minimal risk, and our “descendants” will have more chance to admire each night, an unprecedented light show.
The collision with Andromeda, a galaxy of a size similar to ours, a few billion years later, however, will not be so lenient.