CMB Anisotropy: Measuring Our Motion Through Space

[bwana]

Smoot et. al. have measure a dipole (as well as higher order anisotropies) in the cosmic microwave background. This has been interpreted as our motion through the universe.

so how do we know that the dipole is due to our motion through space and not the anisotropic expansion of space? the only way to know this would be to make measurements from two places that are far apart (one measurement taken within our galaxy and another from outside).

 

[Tuomaaca]

So either we're moving through space in 1 direction, or we're stationary and space is expanding faster on one side of us than the other... ?

It sounds to me like the same thing, just two different frames of reference.

 

[bwana]

right, either we are moving through a spherically expanding space or we are motionless in an expanding weiner. if we were moving through space, shouldn't there be a blueshift in the direction opposite to the redshift behind us?