Questions tagged [big-bang]
According to the current cosmological theories, it's the model that explains the early life of the universe, starting from a rapid expansion of hot and dense matter.
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What does the cosmic neutrino background look like today, given that neutrinos possess mass?
This question is inspired by (or a follow-up to) the threads Where are all the slow neutrinos? and Is it possible that all “spontaneous nuclear decay” is actually “slow neutrino” induced?
The cosmic ...
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Why is the Cosmic Microwave Background evidence of a hotter, denser early universe?
In his book Gravitation and Cosmology, Steven Weinberg says that the Cosmic Microwave Background (CMB) makes it "difficult to doubt that the universe has evolved from a hotter, denser early stage&...
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Is Einstein's theory really challenged by the recent paper in news?
A recent paper authored by Niayesh Afshordi and Joao Magueijo is in the news claiming to challenge Einstein's theory on constancy of light speed. It says light might have travelled with a faster pace ...
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How can something finite become infinite?
How can the universe become infinite in spatial extent if it started as a singularity, wouldn't it take infinite time to expand into an infinite universe?
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How can the universe expand if there is gravitation?
We live in an expanding universe - so I'm told. But how can that be possible? Everything imaginable is attracted by a bigger thing. So, why can't gravitation stop the expansion of the universe? I know ...
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Why did the universe not collapse to a black hole shortly after the big bang?
Wasn't the density of the universe at the moment after the Big Bang so great as to create a black hole? If the answer is that the universe/space-time can expand anyway what does it imply about what ...
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Did spacetime start with the Big bang?
Did spacetime start with the Big Bang? I mean, was there any presence of this spacetime we are experiencing now before big bang? And could there be a presence/existence of any other space-time before ...
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When did the first carbon nucleus in the Universe come into existence?
I am a chemist with a passion for astrophysics and particle physics, and one of the most marvellous things I have learned in my life is the process of stellar nucleosynthesis. It saddens me how my ...
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Given that matter cannot escape a black hole, how did the big bang produce the universe we see today?
Extrapolation of the expansion of the Universe backwards in time using general relativity yields an infinite density and temperature at a finite time in the past.
If the matter contained within our ...
Daniel X Moore
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Conservation law of energy and Big Bang?
Did the law of conservation of energy apply to the earliest moments of the Big Bang? If so, what theoretical physics supports this?
I hear that Einstein's theory of relativity disputes the law of ...
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Why does CMB radiation propagate towards us?
There is something with CMB radiation that does not sit well with me... It seems very counterintuitive that we are able to see it. If CMB radiation formed at the early phases of the universe, would it ...
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Interpretation of a singular metric
I'm interested to find out if we can say anything useful about spacetime at the singularity in the FLRW metric that occurs at $t = 0$.
If I understand correctly, the FLRW spacetime is a combination ...
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Stephen Hawking says universe can create itself from nothing, but how exactly?
Stephen Hawking says in his latest book The Grand Design that,
Because there is a law such as gravity, the universe can and will create itself from nothing.
Is it not circular logic? I mean, how ...
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Big Bang and the Pauli Exclusion Principle
Due to some of the basic principles of quantum mechanics, we have the Wolfgang Pauli exclusion principle, where two fermionic bodies cannot occupy the same quantum state simultaneously. If that is ...
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Does red shift evidence necessarily imply that the universe started from a singularity?
We are taught that the universe began as a singularity - an infinitely small and infinitely dense point. At the beginning of time there was a 'Big Bang' or, more accurately, 'Inflation'.
The main ...
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