10 months ago
Last edited at 12:21PM on 2/21/2013
Since our galaxy is moving, you are asking for another galaxy that is matching the velocity and trajectory of our own galaxy perfectly. If you consider the number of galaxies in the known universe, and the number of potential galaxies beyond it is mathematically reasonable that there should be at least one galaxy that fits that description. But it would be a matter of coincidence, and not a matter of some celestial force keeping them fixed to each other. And since there are more galaxies than the possible number of combinations of speed and trajectory then it is probable that at least two will have identical paths. If you can imagine a room with 366 people in it. It is inevitable that at least two people will share the same birthdays. It's what mathematicians call the Pidgeon hole theory. But it's highly unlikely that we could ever find such a galaxy in the vastness of space, and with our limited technology.