
#19
Jan1312, 11:41 PM

P: 186

One experiment that can give some insight into spacetime curvature is to look at a pulsar as it moves behind our Sun. For a regular pulsar, the interval between pulses should vary with time, if time has a curvature. 



#20
Jan1312, 11:57 PM

PF Gold
P: 322

And now that I mention spacetime, I seem to recall a thread here some months ago, from a mentor no less, to the effect that 'Spacetime is a fantasy' (or a fairytale or someting like that). I will try to find it, though I fear I probably won't understand it. 



#21
Jan1412, 10:57 PM

P: 186

One way of looking at the Universe is to think of it like a Compact Laurentian Manifold. Within this framework, there is no need for expansion into a higher dimension. The Universe doesn’t need to be static, but it can expand or contract. A Compact Laurentian Manifold can allow closed space like and closed time like curves, which may be what is happening near black holes. The Universe doesn’t need to be simply connected.




#22
Jan1512, 06:05 AM

PF Gold
P: 322





#23
Jan1512, 07:50 AM

P: 186

Oops, my bad.
It’s “Compact Lorentzian Manifold.” 



#24
Jan1512, 02:06 PM

Sci Advisor
P: 2,194




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