If massless quanta are the building blocks of the universe how can the universe have mass?

Question

If massless quanta are the building blocks of the universe how can the universe have mass?

Answer 1

The particles inside baryons (protons and neutrons) are zipping around at extremely high energy. That energy is the majority of the mass.

The quarks and glueons themselves are nearly massless.



So most of the mass in the Universe comes from the furious energy of bound quarks.

Answer 2

Properly speaking, it isn't known which is right. The Omega parameter hasn't been measured accurately enough. The errorbar is around 1.01 (which would say finite spatial volume) but includes the case that it is exactly 1.00 (which would make for infinite spatial volume).



But it didn't seem much fun to just answer "don't know".



I took the poll to be asking what is our personal hunch or private opinion. Admittedly we don't know, but which way do you lean?



I lean towards the view that it's likely to be finite spatial volume. that is, the density ratio Omega actually is slightly bigger than 1, say something like 1.01.

And matter seems to be approximately evenly distributed throughout space, so that leads to a finite estimate for matter.



Good poll. It would be interesting to see what other people think, which way they are leaning.



No rigorously correct answer, since the standard cosmological model, LambdaCDM, includes both cases depending on whether Omega exactly one or slightly bigger than one.

Answer 3

That's one of the reasons they built the LHC, to answer that question. Give them some time to get some data from the collider, and analyze it, and maybe they'll be able to tell you. I sure can't.

Answer 4

So. You imply that mass must be a conserved property. That is, mass can only derive from mass.

Would it be fair to say that green can only derive from green? (Not yellow and blue)

Answer 5

Ask me again when we know - we have some hypotheses how this kind of stuff could work, like the Higgs field, but this is not yet a validated theory. It could also be completely different.