Are we absorbing Andromeda, or are they absorbing us?

Question

Of course I am referring to the collision of the two galaxies.

Answer 1

not yet.. but its gonna be a blast....

Answer 2

The two are about the same size, so most likely we'll just form a big elliptical.  Sad, really; I like the spiral shape.

Answer 3

Perhaps one should wait a little, as this collision will not take place for another 5 billion years, and may even not occur as the galaxies may pass close of one another without really "impacting"?

Answer 4

Neither.  The "collision" between Andromeda and the Milky Way will happen in about 5 billion of years.

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Answer 5

If either galaxy would be largely unchanged after the impact, we would say, "the bigger galaxy absorbed the smaller one".  But even though Andromeda Galaxy is several times larger than the Milky Way Galaxy, both will be profoundly changed by the impact, which will result in an elliptical galaxy.  So, the "absorption" is mutual.

Addendum:  Milky Way Galaxy has already "absorbed" (cannibalized) over a dozen minor galaxies, the stretched out remnants still visible to astronomers within the galaxy.

Addendum 2:  A little-known fact:  Our Milky Way Galaxy is not a pretty spiral galaxy like the Andromeda Galaxy.  It's actually a barred spiral galaxy--not so pretty as we once thought.  See link.

Answer 6

The Milky Way will be absorbed by the Andromeda.

Both galaxies have a super massive black hole at our core, but the one in the Andromeda galaxy and the galaxy itself is larger so the Milky Way will be sucked in.  However the collision will be more like a merger than a collision.  Galaxies are colliding all over the universe, but the chances of any matter from one hitting matter from another is pretty slim.

The only reason why I would call it a collision is because if the black holes get near enough to each other then the Milky Way Black hole will be sucked in the by Andromeda black hole; those are probably the only two objects to actually hit each other.  Andromeda contains 1 trillion stars, more than our galaxy but the ratio to dark matter could be in our favor; we don't know much about dark matter though.

Another possibility is that some stars could be flung off into space because of the gravity twist, and there is a third possibility that the two galaxies might actually miss each other.  It depends on how accurate our measurements of Cepheid Variables is.

According to Wikipedia:  http://en.wikipedia.org/wiki/Andromeda_g...

"The Andromeda Galaxy is approaching the Sun at about 300 kilometers per second (186 miles/sec.), so it is one of the few blue shifted galaxies. Given the motion of the Solar System inside the Milky Way, one finds that the Andromeda Galaxy and the Milky Way are approaching one another at a speed of 100 to 140 kilometers per second (62–87 miles/sec.). The impact is predicted to occur in about 2.5 billion years. In that case the two galaxies will likely merge to form a giant elliptical galaxy. However, Andromeda's tangential velocity with respect to the Milky Way is only known to within about a factor of two, which creates uncertainty about the details of when the collision will take place and how it will proceed. Such events are frequent among the galaxies in galaxy groups.

The measured distance to the Andromeda Galaxy was doubled in 1953 when it was discovered that there is another, dimmer type of Cepheid. In the 1990s, Hipparcos satellite measurements were used to calibrate the Cepheid distances. The corrected value gives the Andromeda Galaxy a distance of 2.9 million light-years. Unfortunately, all Cepheids lie further than Hipparcos could measure accurately, and it became clear that Hipparcos-calibrated values for Cepheids were not reliable."

According to Wikipedia:  http://en.wikipedia.org/wiki/Andromeda-M...

"The Andromeda-Milky Way collision is a predicted galaxy collision, due to take place in approximately five billion years time, between the two largest galaxies in the Local Group, the Milky Way and the Andromeda Galaxy. It is often used as an example of the kind of phenomena associated with such collisions in simulations. As with all such collisions, it is unlikely that objects such as stars contained within each galaxy will actually collide, as galaxies are in fact very diffuse—the nearest star to the Sun is in fact almost thirty million solar diameters away from the Earth. (If the sun were scaled to the size of an American quarter, the next closest quarter/star would be 475 miles away). If the theory is correct, the stars and gas contained in Andromeda will be visible to a naked-eye viewer in approximately three billion years. If the collision occurs, the galaxies will likely merge into one larger galaxy.

It is worth noting that there is, as yet, no way to know whether the possible collision is definitely going to happen or not. The radial velocity of the Andromeda galaxy with respect to the Milky Way can be measured by examining the Doppler shift of spectral lines from stars in the galaxy, but the transverse velocity (or "proper motion") cannot be directly measured. Thus, while it is known that the Andromeda galaxy is getting closer to the Milky Way by about 120 km/sec, there is no way to tell whether it is going to collide, or miss. The best indirect estimates of the transverse velocity indicate that it is less than 100 km/sec. This suggests that the dark matter halos, although possibly not the actual disks, of the galaxies will collide. A future European Space Agency spacecraft, the Gaia mission, expected to launch around 2011, is intended to measure the positions of stars in the Andromeda galaxy with sufficient precision to pin down the transverse velocity...

Such collisions are relatively common—Andromeda, for example, is believed to have collided with at least one other galaxy in the past It is possible, but not certain, that our Solar System may be ejected from the new galaxy some time during the collision. Such an event would have no adverse effect on the system (especially since Sun is projected to enter red giant phase in 5-6 billion years). Chances of any sort of disturbance to the Sun or planets themselves are remote."

Answer 7

Since we're roughly the same size and moving towards each other, it will be more of a merger than one galaxy absorbing the other.

Us: You got Andromeda in our Milky Way!

Them: You got Milky Way in our Andromeda!

If humans (or our evolutionary descendants) are still around, we'll have to figure out what to call the newly-merged galaxy.  If we keep the same name, the I guess from our perspective, we will have absorbed Andromeda.