What will happen when our galaxy collides with another galaxy?

Question

Basically wondering whats the Earth will feel when it happens.

Answer 1

Galaxy collisions are not a life-threatening event. All the stars and planets of both of the galaxies pass through each other unaffected. The main effect is on the gas in the two galaxies----initially, there may be an increase in pressure of the interstellar gas. This may reduce the size of the helopause (the place where the solar wind ends and interstellar space begins), but it is unlikely that the helopause would contract so much that it was inside the Earth's orbit. This would be bad because it would allow the interstellar medium to reach the Earth, causing an increase cosmic rays. The collision might cause in increase in the number of nearby supernovae. A very nearby supernova (within 15 lightyears) is bad for life on Earth.
Eventually, as the collision continued, the interstellar medium would be swept away and we would get a much better view of the (now distorted) Milky Way and the other galaxy.

The Milky Way has collided with many small galaxies in the past. It collides regularly (every billion years or so) with the Magellanic Clouds. These galaxies, being small, don't affect very much of the Milky Way at one time.

In a few billion years from now, the Milky Way will collide with the Andromeda galaxy, M31. This galaxy is similar in size to the Milky Way. The collision will substantially change both galaxies. By then, the Sun may be a White Dwarf star.

Answer 2

In the southern hemisphere there is The Andromeda Galaxy that is on a collision coarse with the Milky Way it will happen in about a million years there is a chance that stars will collide making some really big fireworks

Answer 3

Andromeda galaxy is the closest galaxy to the milky way galaxy and is scheduled to collide with us sometime before the sun turns into a red giant star.

Answer 4

The Earth will likely be bombarded with a lot more radiation, as the gravitational effects of the collision will likely initiate a burst of rapid star formation. Actual stellar collisions and collisions of planets aren't that likely, as most of the galaxies will be emptry space.

That is of course assuming that the Earth is still there when it happens.

Answer 5

Nothing.... There is so much empty space inside each galaxy that the galaxies merge together and start rotating around a common center as one but the stars do not collide with each other...

Answer 6

Our galaxy is nowhere near another galaxy so it's not going to collide with anything on that scale. The Earth's biggest concern should be asteroids which can hit and cause massive earthquakes and tidal waves.

Take out a globe and look at the shapes of places like Hudson bay or the Gulf of Mexico and realize that these enourmous geographical features were puched out of the Earth's topography by asteroids. Eek!

Answer 7

There's a rather extensive article on exactly this question in the October 2006 issue of "Sky and Telescope", page 30 titled "The Great Milky Way / Andromeda Collision".

Coming to a sky near you in November of 3000002006.

Answer 8

The "collision" will take millions of years to occur. The earth may get moved out of orbit, maybe not, impossible to tell, maybe the sun will be on the far side.

Answer 9

if 2 collided then the stars would crush slowly to begin with. the gravity will increase in that area and the speed of crushing will increase. i assume it would be a gigantic long explosion. maybe once its all crushed it will cause a big bang type explosion. or maybe would die out like a supernova.

Answer 10

Don't lose sleep over it. If it does happen, it is not expected for another 15 million years. Look at Antennae though.....