According to special (& galilean) relativity, there is no difference between constant movement or not moving at all but it is possible to detect acceleration and rotation is acceleration.
The earth rotates around the sun and the sun rotates around Sagetarius A* (the black hole in the center of the milky way).
So, there should be small accelerations directed to the center of rotation all the time.
Are those accelerations detectable? I think that it should be easily possible to detect the earths rotation around the sun but what about the rotation of the milky way?
Also, does the milky way accelerate in any direction or is it moving constantly?