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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.

According to the current cosmological theories, the Big Bang is the model that explains the early life of the universe, starting from a rapid expansion of hot and dense matter.

This inflation is described by the Friedmann equations, a special case of the Raychaudhuri equation.

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Is it possible to look into the beginning of the Universe?

If we currently can look into some of the furthest stars, actually seeing the past Isn't it conceivable that given enough distance we should be able to see Parts of the Big Bang? If the Universe is endless, it means we should be able to see into…
Asaf
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What would the universe look like if it started out without any irregularities?

(Warning! Newbie question coming up!) Background As seen on this picture of the cosmic microwave background (take from the Wikipedia entry on the very same topic) there exists irregularities in the distribution of matter: To my knowledge, this is…
Speldosa
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Looking for review articles on big bang nucleosynthesis

Can someone point to a good review article covering contemporary developments in big bang nucleosynthesis, beyond what's covered in Kolb and Turner's The Early Universe? Thanks.
felix
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Light years and redshift from our point of view. How can we see it?

So I was reading about GN-108036 this morning and for some reason I thought of something which I can't quite wrap my head around and make sense of. It's early morning so maybe coffee hasn't kicked in yet. If it starts with a central big bang and we…
jfrobishow
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Infinite Universe and the big bang

OK, I was thinking of the big bang and how it relates to an infinite universe. If the universe is infinite is mass and there was a big bang, then at the big bang there was an infinite amount of matter in an infinitely small point. If space expanded…
cleerline
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What information do we have about time before the big bang?

I've heard for awhile now that a lot of physicists think that time was created in the big bang as a dimension (just like space). When I try to look this up online though i just get on old lecture from Stephen Hawking about why that may or may not be…
A studly muffin
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Where is the missing energy from the Big Bang?

"They" say the Big Bang created 1 billion particles of anti-matter for every 1 billion and 1 particles of normal matter. That the 1 billion particles of anti-matter were annihilated when they met 1 billion matter particles, thus leaving 1 matter…
Coyote62901
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Energy and Matter

I was watching a show about the big bang theory. They were saying that in the beginning all that existed was energy. After the big bang that energy transformed into matter which then started forming into different elements. How exactly does…
Linger
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Which big bang theory has more assumptions?

I'm trying to compare the two most popular big bang theories, the big freeze and the big crunch or big bounce theory, and apply Occam's razor, which says the more assumptions a solution has, the more likely it is wrong. First of all, if the universe…
rowanman28
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Is it possible for another Big Bang event to occur inside our universe?

And if it were, would it constitute an expanding bubble in our universe - with a definite (expanding) surface. That would be nice - none of this irritating "everywhere is the centre and there is no edge" business... But would it have the mass of our…
colinh
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At what temperatures did various atomic and subatomic particles begin to form?

I've been simulating the expansion of the universe using the Friedmann Equation and some numerical integration in python. I've been able to calculate the temperature of the universe by dividing the current temperature (2.73K) by the scale factor. Is…
Sam Kennedy
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Assumption in Lambda CDM model

I just read that the Lambda CDM model assumes that General Relativity holds on a cosmological scale. Could someone please explain to me why that assumption would be needed? General relativity is the best theory of gravity we have right now. What…
user45922
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Why not the big crunch?

Entropy As per the second law of thermodynamics "Order tends to disorder" And recently I watched a video series by minute physics 3:25 The Big Picture: Entropy & Time (feat. Sean Carroll)S1 • E1 Why Doesn't Time Flow Backwards? (Big Picture Ep.…
user39460
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Were the known laws of physics valid at the Big Bang?

Did the currently known laws of physics also come into existence at the time of the big bang? What about the various constants such as mass of electron or speed of light? Did these also come into existence or are they part of the novelty of the big…
good_ole_ray
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How is the potential infinitude of the universe compatible with the Big Bang?

I know no physics, but I read that while the observable universe is finite, for all physicists know the universe is infinite. How is this compatible with the Big Bang hypothesis? Does it mean that it's possible that at some point space expanded at…
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