From David Clark
Space itself spinning? Truly revolutionary! If it is, then surely it must have a centre. Furthermore, the Universe would then have a plane of rotation, and so not look the same in all directions – another U-turn for my confused brain to try to absorb. Phew, gotta go…my head is in a spin!
Eugenie Samuel writes: There are solutions to Einstein’s equations of general relativity in which the Universe rotates. In these models, there is no centre of rotation. Instead, particles at every point appear to experience an accelerating force. This does indeed mean that the Universe would not look the same in all directions and detailed observations of this could be another way of detecting the spin.
Sandy Bay, Tasmania
