No Hydrogen Formation: Conditions for a Radiation-Only Universe

In summary, it is still an open question as to why the universe has an excess of matter over antimatter.
  • #1
wolram
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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?
 
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  • #2
permanent high temperature? which would mean no expansion of the universe I suppose.
 
  • #3
wolram said:
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?
 
  • #4
Astronuc said:
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 :smile:
But were the conditions for hydrogen inevitable in our universe?
 
  • #5
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.
 
  • #6
mathman said:
If you start with the big bang conditions -
But what preceeded the Big Bang? What were the precursors? That question will never be answered.

mathman said:
. . . 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.
 
  • #7
wolram said:
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.
 
  • #8
SpaceTiger said:
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.
 

1. What is a radiation-only universe?

A radiation-only universe refers to a hypothetical universe where the only form of energy present is radiation. This means that there is no matter or dark matter, and all interactions and processes are governed by radiation.

2. How is hydrogen formation related to a radiation-only universe?

Hydrogen formation is a key process in the evolution of a universe, as it is the first element to form after the Big Bang. In a radiation-only universe, the lack of matter and dark matter means that the formation of hydrogen is much more difficult and may not occur at all.

3. What are the conditions necessary for a radiation-only universe to exist?

In order for a radiation-only universe to exist, there must be a high density of radiation and a lack of matter and dark matter. This could potentially occur in the very early stages of the universe or in extreme environments such as the interior of a black hole.

4. How does a radiation-only universe impact our understanding of the universe?

A radiation-only universe challenges our current understanding of the universe and the role of matter and dark matter in its evolution. It also raises questions about the nature of radiation and its role in shaping the universe.

5. Is there any evidence for a radiation-only universe?

Currently, there is no direct evidence for a radiation-only universe. However, some theories and models suggest that it may have existed in the early stages of the universe or in certain extreme environments. Further research and observations are needed to determine the validity of these theories.

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