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14

Free neutrons can be generated by spallation reactions between cosmic rays and heavy metal targets. Such processes do occur in the cosmos. The free neutrons will then beta decay to yield protons (hydrogen nuclei) and electrons. This is a weak reaction, so the protons produced here were not present shortly after the big bang. So not all hydrogen atoms ...


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I believe a great answer to your question is: We don't know We still can't resolve the time before electroweak interactions, so how can we even come close to answering this question? You might get answers from some theories (or I prefer to call them theorems because they're only math until today) like string theory or loop quantum gravity or M-theory or ...


6

This is a metaphysical/philosophical question, imo. There is the platonic ideals school, in this case read for ideals=mathematics, which postulated that ideals existed and nature fell into their form. I have seen a number of theoretically inclined people who are really of that school. One does not have to think of the beginning of the universe to start ...


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As far as I understand, Physics is not able to awnser this question, because the physical laws we use to describe the Universe are not valid up to the exact event of the Big Bang (the Big Bang is said to be a singularity of spacetime). Physics attempts to describe the Universe at a moment when it already existed, but does not states causes for its existence ...


3

Why is the gravitational constant.. constant? We don't actually know that it is. Check out the Dirac Large Numbers hypothesis: "According to Dirac's hypothesis, the apparent equivalence of these ratios might not be a mere coincidence but instead could imply a cosmology with these unusual features: The strength of gravity, as represented by the ...


3

In a static universe it would indeed be true that if you looked at an object, say, 10 billion light years away you would be looking at it as it had been 10 billion years ago. This isn't really an application of special relativity and is merely a consequence of a finite speed of light. Our universe, however, is expanding and so you can actually see across ...


2

We cannot see anything closer than 380,000 years after the big bang because that is when radiation and matter decoupled. The CMB is a picture of what the universe looked like at that point. All clumping of matter into stars, galaxies, etc has occurred since then. If we had looked 1 billion years ago, we would see the same except that the CMB temperature ...


2

A comoving observer and an observer that has been moving at $0.866c$ since Big Bang will disagree on their measured age of the Universe by a factor of 2. While both measurements are correct, we can say that the comoving observer measures a more "natural" age of the Universe. For instance, the comoving observer is the only observer who will measure the ...


2

Suppose two observers, Alice and Bob, are moving relative to each other since the beginning of the universe. While they do it, they construct the chronologies of all the events of the universe, as they record them in their frame of reference. They will construct different chronologies. However, and this is key, each can reconstruct the other's chronology. ...


2

Actually there is a geometry that describes something like the naive idea of the Big Bang. But it's a bit of a cheat because it's really just a piece of the usual expanding universe metric. The first metric suggested to describe a collapsing star was the Oppenheimer-Snyder metric, which describes a spherical ball of dust collapsing under its own gravity. ...


1

The term Big Bang does not have rigorous physical definition. And if you mean specifically inflation, then the modern inflationary models (chaotic inflation with various scalar field potentials) predict that inflation is always present at certain regions of space. Inflation is driven by a scalar field, the value of which lowers with time. When it drops ...


1

Semantics is wrong in more than one way. First of all, there is no "first" without time, and time only exists in the universe, so the question is not well posed. If there was something before the big bang, then both are a part of the same "universe/multiverse" for which common laws must hold (you can't just discretely switch laws all of the sudden - and if ...


1

Pulling together what's been said in various comments: 1) General relativity admits models where spacetime is foliated by spacelike leaves, all of which are indexed by a global time coordinate. The simplest of these models is Minkowski space. All of your observations about models with comoving observers apply equally well to Minkowski space, so if you ...


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What would happen if you were to release the energies of the big bang in our universe a second time? Have a look at this standard history of the universe, History of the Universe - gravitational waves are hypothesized to arise from cosmic inflation, an expansion just after the Big Bang Our universe is now at the far right. Note the beginning ...


1

Philo's answer is spot on, and I'll basically be rephrasing it here into a form that makes more sense to me. Hopefully it will help some others as well. Rather than only dialing back the clock 1B years, let's go waaaay back and see what things look like: we go back 13.82B years and look out into space... And there's no space! The universe is very ...



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