No Hydrogen Formation: Conditions for a Radiation-Only Universe

[wolram]

AFAIK hydrogen was one of the first elements in our universe, i came to
wonder, what conditions would prevent hydrogen from forming, and our
universe consisting of only radiation?

 

[inha]

permanent high temperature? which would mean no expansion of the universe I suppose.

 

[Astronuc]

AFAIK hydrogen was one of the first elements in our universe, i came to
wonder, what conditions would prevent hydrogen from forming, and our
universe consisting of only radiation?

That question may never be answered.

One could just as well ask, why are the elementary particles the size that they are? Why is the charge what it is? and so on.

What one may ask is - how and why were the initial conditions of the universe (or all of existence), and all of matter and energy, and for that matter time, established?

 

[wolram]

That question may never be answered.

One could just as well ask, why are the elementary particles the size that they are? Why is the charge what it is? and so on.

What one may ask is - how and why were the initial conditions of the universe (or all of existence), and all of matter and energy, and for that matter time, established?

If there are two ways to ask a question i always pick the wrong one
But were the conditions for hydrogen inevitable in our universe?

 

[mathman]

If you start with the big bang conditions - extremely small volume and extremely high energy density, then hydrogen formation (or more specifically quark-antiquark and electron-positron pair production) is inevitable, assuming that the laws of physics are inevitable. A still open question is how did the excess of matter over antimatter come about.

 

[Astronuc]

If you start with the big bang conditions -

But what preceeded the Big Bang? What were the precursors? That question will never be answered.

. . . assuming that the laws of physics are inevitable. A still open question is how did the excess of matter over antimatter come about.

That's a BIG assumption. Yes, it is an open question. But how do we know that there is an excess of matter over antimatter. We cannot see the entire universe. We may be way off center.

 

[SpaceTiger]

AFAIK hydrogen was one of the first elements in our universe, i came to
wonder, what conditions would prevent hydrogen from forming, and our
universe consisting of only radiation?

There are answers to the first part of the question that don't lead to the second. For example, if the rate of the expansion of the universe were much slower and the density much higher, then nucleosynthesis could have led only to the formation of elements much heavier than hydrogen. There are a ton of other initial conditions one could contrive that would lead to a lack of hydrogen. Mostly notably, if matter and antimatter were exactly symmetric and in equal abundance, then all matter would annihilate and you'd be left only with radiation. Another easy way would be to simply start without any baryons.

 

[Danger]

There are answers to the first part of the question that don't lead to the second.

It'd be interesting to see what would happen if Planck's Constant was 5, but I don't think I'd be around to witness it.