Galaxies can also have modest local motions as they mill around and gravitationally pull on one another—as the Milky Way and Andromeda are doing.
Galaxies can also have modest local motions as they mill around and gravitationally pull on one another—as the Milky Way and Andromeda are doing.
星系在成群的整体运动之外，也可以有适度的局部运动，并受彼此间的重力牵引──银河系和仙女座星系之间就是如此。