How Cn Gravity Affect Light When Light Has No Mass?

[polymath257]

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But definition aside, it does not take neutral atoms to cause gravity.  It does not even take protons or neutrons or electrons to create gravity.   Smash matter into their continue to quarks, the shattered subatomic particles together with the liberated binding energy that formerly held together excertd precisely the same gravity as their when they were assembled into anything you might call matter.

The total gravitational energy of the universe is fixed, however the constituent parts of the universe evolves.

I know the textbook answer, but do you think matter/mass causes gravity or space time curvature?

Yes. gravity *is* spacetime curvature. Mass and energy (as well as momentum density) created the curvature of spacetime via Einstein's equations.

At least for physicists, protons, neutrons, and electrons are matter whether or not they are combined in atoms. And all of those existed before recombination. In fact, they all existed *very* in the expansion phase with most atomic nuclei being formed from protons and neutrons in the first 3 minutes or so.

The recombination phase didn't hit until about 300,000 years into the expansion.

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I don’t believe that is accurate for two reasons:

1.  Recombination refers to electrons pairing up with protons.  They existed separately as ionized plasma before.   So there were matter before recombination, just not electrically neutral matter.
2.  Even if there were not electrons and protons, If there were photons, there were gravity.  Gravity is an artifact of energy in all forms, not just in matter form.   If I am not mistaken, most of the gravity of normal matter is not from the rest mass of the particles with rest mass, but from binding energy that holds These particles together.

In relation to this discussion, I must disagree with both your points.
1.Quanta is not matter but the constituent parts of matter, just as hydrogen and oxygen are the constituent parts of water. That's why quantum mechanics is different from classical mechanics because qunta doesn't follow the laws of matter. The smallest unit of matter is the atom. There are hydrogen atoms. There aren't any hydrogen protons.
2. subatomic particles are held together by the strong force (gluons) which is entirely different from gravity. Before quanta were brought together by the strong force during recombination, there were no atoms, ergo, no matter. Photons may have produced gravity but gravity is a weak force. It wan't enough to held quarks together.

OK, 'quanta' were NOT brought together during recombination. Nuclei (that had already formed much earlier) and electrons combined at that point to form neutral atoms. But there was plenty of matter long before that in a plasma form. The strong force reactions were mostly completed by about 3 minutes into the expansion, with the light elements formed by that point. Heavier elements weren't formed until the development of stars much later on.

Second, there is no type of particle called a quantum. Instead, ALL fundamental particles are considered to be quanta for their fields. So, photons are quanta of light, up quarks are quanta of the up field, etc.

Actually, a proton is a hydrogen nucleus, so a bare proton is often symbolized as an H^+ ion. In that sense, 'hydrogen proton' is redundant, not contradictory.