galactic merger?

wolram

i have read that our galaxy is being pulled towards
the great attractor, also that the speed of gravity
is equal to C, if both of the above are correct then
our galaxy is being pulled to a position that the
great attractor was in the past, i dont know how far
away the GA is but for dscusion purposes only say
it is 100LYs, that would mean that our galaxy is
being pulled to a position occupied by the GA 100
years in the past, now if i suggest that the GA is
mooving at a right angle to the line of travel our galaxy then they
could never merge.
why is my thinking wrong?

mathman

Under your assumption our galaxy would be moving in a curved path, which would eventually hit the direction vector of the great attractor and pointing toward it. Whether it merges at that time or later depends on how fast the great attractor is moving relative to our galaxy.

Labguy

Yes, it is just like the gravitational effect on any "merging" system of multiple bodies. The fact that is on a >galactic scale is no more or less than on a much smaller scale.

Just think of it like the familiar "protostellar disk" forming a star and planets. The attraction does not pull all the material directly to a single center of mass in a straight line. The material (galaxies in this case) will approach on vectored (curved) paths and spiral closer and closer as they get nearer. Some galaxies may directly merge by chance collision, but most will spiral in with increasing V until they are close enough to collide and/or merge into a large, fat biggie. On this scale, we are probably talking billions of years and maybe even more than the present age of the universe. This is for our large-local group. The same thing is going on in other huge areas of the universe.

Labguy.

wolram

now all is clear thanks