A raisin's relative position inside the cake does not change, ie it is not moving. But as the volume of the cake increases, the raisins get farther apart. Similarly, the galaxies in the universe are getting farther apart, but they aren't necessarily moving through space.
Make sense?
To see if I am following you guys about what it means for space to expand..
If there were a giant tape measure between two galaxies and I made a reading at one moment.
Then I take a vacation and read it again, does it now measure greater than previously?
Or does the tape measure expand with space and read the same as before?
Also what book might be a good choice to learn about current cosmology for someone with about 5 years of science/engineering background, but no previous coursework in cosmology?
Thanks in advance if anyone fields an answer..