Matterwave's latest activity

A subjective experience is not, at least definitionally, the same thing as its objective manifestation in the brain. If you want to make...

You don't need to do anything fancy, it's basically just a bunch of plug and chug and being very careful with every term. Take...

Yes. That is what I mean. ##T^{\mu\nu}\ne 0## implies ##R^\mu{}_{\nu\eta\xi}\ne 0##. But ##R^\mu{}_{\nu\eta\xi}\ne 0## does not imply...

Only if we measure both spins in the same direction. (And even that ignores the difficulty of how we can ensure that we are measuring...

Gotcha, thanks for clarifying! It depends a bit on what you mean by "source". If you mean just your criterion ##T^{\mu\nu}=0## then I...

I mean every vacuum spacetime (##T^{\mu\nu}=0##) with curvature (##R^\mu{}_{\nu\eta\xi}\ne 0##). That includes the various gravitational...

There are research papers investigating the gravitational effects of light (as a source), see, e.g.: https://arxiv.org/abs/1511.01023...

That's the answer I was looking for. Thank you.

Could you clarify? There's a few different possible things you could mean with this, and I'm not sure which one (or all of them) you're...

The spacetime is curved by the source mass (e.g. the "M" in the Schwarzschild metric). Light itself is massless and will travel along...

The mass of a moving rock is ##{E \over c^2}\sqrt{1-v^2/c^2}=m##. The photon is massless because it is moving with ##c##: ##{E \over...

That's a matter of definition. In modern physics (last few decades, mostly), when we say "mass" we mean the invariant mass (a.k.a rest...

No mass is needed in GR - it's a theory of curved spacetime and particles in free fall follow geodesics (the generalisation of straight...

Use the Attach Files button just below the reply box. Once you've uploaded a file a thumbnail will appear below the reply box. Click on...

A mathematician showed me another way to see the 3 sphere. Slice the 3 sphere along its equatorial 2 sphere. Its two hemispheres are 3...