Eventually all galaxies, including our Milky Way, will come to an end.
So how do galaxies die? If you’re in the mood to destroy an entire galaxy, you have a few options depending on the level of destruction you want.
Relating to: Monstrous black holes may have killed host galaxies in the early universe
Option 1: Awaken the monster black hole
There is a supermassive black hole at the heart of almost every galaxy. In the Milky Way example, Spring A*A monster weighing more than 4.5 million suns. Usually these giant black holes are quiet and motionless, swallowing gas or star particles that wander too close by. But sometimes they feast on a much larger meal. When they do this, the gas rotates around them and becomes compressed, reaching temperatures well above a billion degrees.
These ridiculously high temperatures cause the gas to emit tremendous amounts of radiation, which then floods the entire area. galaxyIt heats gas reserves and prevents the formation of new stars. While things generally calm down after this, in the worst cases, radiation from the device’s surroundings black hole It can completely remove large amounts of gas from the galaxy.
This doesn’t completely destroy a galaxy, but it effectively kills it by preventing new stars from forming for a very long time, in some cases forever.
Option 2: Drop into a cluster
Galaxy clusters are dense urban centers of the cosmos, often home to a thousand or more galaxies. But these clusters contain more than just galaxies; they also host large reservoirs of a hot, thin gas known as the intracluster medium (ICM).
The ICM is so thin that it would be perceived as a vacuum in laboratories on Earth. However, when galaxies fall into a cluster, they still have to pass through the cluster. Initially, this leads to a brief round of star formation as shock waves compress gas clouds in the galaxy. But eventually the pressure of the gas does its job and collects bits of gas from the galaxy, like debris flying from a meteorite.
This leads to a cute situation known as “”.jellyfish galaxiesIt is so named because the stripped gas resembles the tentacles of a jellyfish. Although most galaxies survive their descent into the cluster’s ICM, some smaller galaxies are completely evaporated.
Option 3: Crash into another galaxy
Galaxy collisions represent one of the largest releases of energy in the known universe, which means it’s not a pretty sight. Our own Milky Way will collide with our neighbor galaxy Andromeda about 5 billion years.
Galaxy mergers, a slow and painful process that takes hundreds of millions of years, can give rise to massive tidal tails of broken streams of stars and gas that arc around galaxies. During collisions and mergers, countless stars are lost due to random interactions. And when the respective supermassive black holes meet, a new round of radiation hits the newly merged galaxy. The combined destruction depletes the galaxy’s gas reserves, effectively halting star formation entirely.
Option 4: Feed it to a much larger galaxy
If a smaller galaxy merges with a much larger companion, this could mean the end of the smaller galaxy. In fact, the European Space Agency Gaia The research discovered the bones and corpses of cannibalized galaxies scattered throughout the Milky Way.
One such example is known as: Gaia sausage. This collection of stars scattered around the Milky Way shares core features that differ from the rest of the population, such as abundance of heavy elements and orbital parameters. Astronomers think the stars in the Gaia sausage are the shattered remains of a small dwarf galaxy that was torn apart by its merger with the larger Milky Way.
Astronomers have identified dozens of other such collections, streams, clusters, and remnants; This is a sign of the violent merger history of any reasonably sized galaxy like ours.
Option 5: Just wait
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Eventually time will do its job. Galaxies are quite stable; many have existed for more than 10 billion years. But nothing lasts forever.
In the far, far future, when the universe is many times older than it is today, the Milky Way-Andromeda galaxy merger will begin to unravel. It’s just a matter of gravitational luck. Most stars don’t spend most of their lives in close proximity to each other, but occasionally they get very close. When they do this, they do a little gravitational dance, sending them in new directions. Very occasionally, enough energy can be obtained to escape the galaxy completely.
This is incredibly rare, but it’s bound to happen over trillions and trillions of years. Eventually everything in our galaxy will either collapse into a giant black hole or be dispersed throughout the wider universe. And this will truly be the end of our galaxy.