The Milky Way and Andromeda Galaxies on Collision Course
It sounds almost like something out of a science fiction movie. Two giant barred spiral galaxies on a collision course, set do destroy all life.
Well, as it turns out that is, at least partly, going to happen.
Scientists have long suspected that it was a possibility that our own Milky Way galaxy and the nearby Andromeda galaxy - its about 2.5 million light-years away - could possible collide and merge into a single galaxy.
Now NASA scientists working with the Hubble Space Telescope have confirmed that indeed the two galaxies are on a collision course.
Researchers estimate that the two galaxies will meet in about four billion years. And as the two largest members of our Local Group approach each other in about 3.75 billion years from now the Andromeda galaxy will virtually fill the night sky, while the Milky Way galaxy will be visibly warped by the gravitational pull of the approaching galaxy.
The result of the merger will create a giant elliptical galaxy. In fact, researchers hypothesize that all giant elliptical galaxies are the result of mergers of spiral galaxies (or in this case, barred spiral galaxies).
The third largest galaxy (behind the Milky Way and Andromeda) in our Local Group - a group of at least 54 galaxies that gravitationally interact in this region of the Universe - is the Triangulum galaxy.
The Triangulum galaxy is actually a satellite galaxy of Andromeda. And there is actually a small chance that as Andromeda approaches the Milky Way that it could whip the Triangulum galaxy around into our Galaxy first.
It is more likely, however, that the Triangulum would be absorbed by the Andromeda/Milky Way merged galaxy at some later point.
The effects on our solar system are not entirely clear. Much of what happens to our little neighborhood, if you will, depends on how the Milky Way and Andromeda collide.
Simply because the Milky Way is merging with another galaxy does not mean that the solar systems within it are in danger. In fact, the Milky Way is currently absorbing three other, much smaller galaxies. And two more, the Magellanic clouds will eventually become part of our home galaxy as well. The difference, really, is only the scale of the galaxy we are merging with.
The most likely scenario is that we will be flung into some new part of the galaxy, which will actually at that point be a whole new galaxy.
But because of the relatively large distance between stars in the galaxies - and the fact that we are nowhere near the galactic center - it is unlikely that there would be some catastrophic collision between our Sun (or Earth) and some other object.
The Sun will find a new orbit around the core of the newly formed galaxy. As for life? Well, we certainly will not be here any more. As the Sun's luminosity continues to increase over time - just a part of the stellar evolution process - eventually any life on Earth will not be sustainable.
So unless humans have the ability in the next billion years or so to travel to other solar systems, life here will cease to exist. But in theory, any life forms in the galaxies should be able to survive just as long as their solar systems remain relatively in tact, which is a very reasonable possibility.
Well, as it turns out that is, at least partly, going to happen.
Collision Course
Scientists have long suspected that it was a possibility that our own Milky Way galaxy and the nearby Andromeda galaxy - its about 2.5 million light-years away - could possible collide and merge into a single galaxy.
Now NASA scientists working with the Hubble Space Telescope have confirmed that indeed the two galaxies are on a collision course.
Researchers estimate that the two galaxies will meet in about four billion years. And as the two largest members of our Local Group approach each other in about 3.75 billion years from now the Andromeda galaxy will virtually fill the night sky, while the Milky Way galaxy will be visibly warped by the gravitational pull of the approaching galaxy.
The result of the merger will create a giant elliptical galaxy. In fact, researchers hypothesize that all giant elliptical galaxies are the result of mergers of spiral galaxies (or in this case, barred spiral galaxies).
Not Just Andromeda
The third largest galaxy (behind the Milky Way and Andromeda) in our Local Group - a group of at least 54 galaxies that gravitationally interact in this region of the Universe - is the Triangulum galaxy.
The Triangulum galaxy is actually a satellite galaxy of Andromeda. And there is actually a small chance that as Andromeda approaches the Milky Way that it could whip the Triangulum galaxy around into our Galaxy first.
It is more likely, however, that the Triangulum would be absorbed by the Andromeda/Milky Way merged galaxy at some later point.
Effects on Human (or Alien) Life Forms
The effects on our solar system are not entirely clear. Much of what happens to our little neighborhood, if you will, depends on how the Milky Way and Andromeda collide.
Simply because the Milky Way is merging with another galaxy does not mean that the solar systems within it are in danger. In fact, the Milky Way is currently absorbing three other, much smaller galaxies. And two more, the Magellanic clouds will eventually become part of our home galaxy as well. The difference, really, is only the scale of the galaxy we are merging with.
The most likely scenario is that we will be flung into some new part of the galaxy, which will actually at that point be a whole new galaxy.
But because of the relatively large distance between stars in the galaxies - and the fact that we are nowhere near the galactic center - it is unlikely that there would be some catastrophic collision between our Sun (or Earth) and some other object.
The Sun will find a new orbit around the core of the newly formed galaxy. As for life? Well, we certainly will not be here any more. As the Sun's luminosity continues to increase over time - just a part of the stellar evolution process - eventually any life on Earth will not be sustainable.
So unless humans have the ability in the next billion years or so to travel to other solar systems, life here will cease to exist. But in theory, any life forms in the galaxies should be able to survive just as long as their solar systems remain relatively in tact, which is a very reasonable possibility.
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