# All Questions

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### “All energy gets taken from the particles and put into the fields”. What does that mean?

In the The Emperor's New Mind book. While author explains why classical physics fails to explain our universe, says: The root cause of these is that two kinds of physical object must coexist: ...
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### At what speed will objects hit a singularity? [duplicate]

I have read in numerous places like here that an object in free fall into a black hole will be travelling the speed of light when it passes the event horizon. How is it possible to go this fast? ...
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### How to prove the Hubble law is the unique expansion law compatible with homogeneity and isotropy?

In the book physical foundations of cosmology, it saids that Hubble law is unique and a problem seems to be a hint of proving that. In order for a general expansion law,v=f(r,t), to be the same ...
Suppose there is an entangled state of two electrons, the spin part is $$| \downarrow \uparrow \rangle - | \uparrow \downarrow \rangle \tag{1}$$. If I add the spatial part of the wavefunction as two ...