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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How was the universe created?

I do not know much beyond high school Physics. Thus, I am asking this question from almost layman's perspective: What, as per the best of our existing knowledge and widely accepted among the ...
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Connection between BAO und CMB Spectrum

I have a problem understanding the connection between the accoustic peaks in the CMB spectrum and the baryon oscillation picture. On the one hand it is stated, that the odd accoustic peaks (1,3,5..) ...
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238 views

Frame of reference and big bang

I have read Brief History of Time in which he has wonderfully described the formation of universe. What is the frame of reference from which we are viewing the big bang? What is the frame of reference ...
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545 views

Does (it make sense to say that ) the universe has a center?

I was reading this page: http://www.guardian.co.uk/science/2011/oct/23/brian-cox-jeff-forshaw-answers and I found this sentence by Brian Cox: That seems to imply that everything is flying away ...
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If randomness doesn't exist, how come the universe isn't a perfect sphere with predictable distribution of matter?

I'm presuming that the scientific community pretty much agrees that randomness doesn't exits, and that everything has a cause. Please correct me if I'm wrong, I've heard of quantum mechanics, but as ...
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How is Big Bang related to theory of relativity?

I'm not someone with good scientific knowledge, so if my question are weird, correct me. I was reading about big bang and I came by the theory of relativity. Can someone explain the relation between ...
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58 views

Could there be a sort of “Molecular Destiny”?

Let's say we start with the Big Bang. Every bit of matter started from this event. Therefore, given EVERY variable (every particle, movements of particles, weights, times, etc) and an INFINITE amount ...
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2k views

What did Hawking mean? 'Time started at the big bang'. Book suggestions please [closed]

After writing down this question, I have come to realize that. What I really want is reading materials on the questions below. Before the big bang there was no such thing as 'time' (Steven Hawking on ...
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23 views

The Helium mass fraction from the Big Bang Nucleosynthesis

In Perkin's book Particle Astrophysics (page 144): I do not understand how one comes to the following expression (the second equality with $r$) for the Helium mass fraction due to the Big Bang ...
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240 views

Did force of gravity cause evolution of large scale structures?

Did big bang create gravity? What role gravity is assumed to have played in the formation (starting from the big bang) of large structures of our universe and what other important physical mechanisms ...
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81 views

Where did the universe get its initial momentum?

If, according to Newton's third law, forces come in pairs then what about the big bang? where did the universe get that initial push/momentum?
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Is it possible that galaxies' redshift is caused by something else than the expansion of space?

I was thinking that maybe photons loss energy naturally when they travel great distances. Or maybe the mass of all matter is increasing over time and therefore photons emitted in the past are ...
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114 views

Immediately after the Big Bang, was the universe in a state of extremely low or extremely high entropy?

Phase space theory suggests that the largest course-graining region, $p$, in a phase space, $P$, is the point in the phase space with the highest entropy. As such, it is in thermal equilibrium with ...
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105 views

What was ticking just after the Big Bang?

When reading about the Big Bang, I see phrases like 3 trillionths of a second after... So, what was ticking to give a time scale like this? We define time now in terms of atomic oscillations, but ...
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1answer
118 views

Reference request for low entropy big bang

There is a somewhat widely accepted argument that the second law of thermodynamics exists because the universe began in a low-entropy state. I'm writing a paper that mentions this (and must be ...
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1answer
89 views

Why do we need the concept of dark energy to explain the expansion of the universe?

Why can't the expansion of the universe be thought as the Big Bang itself still in progress? Why do we need to introduce dark energy? The Big Bang was powerful, and that explosion itself could still ...
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283 views

Why every galaxy is moving away from every other galaxy on astronomical scale? because of an explosion or because of creation of space?

Why galaxies move away from each other in general on the astronomical scale? Which answer is correct of the following? It is because of the big bang theory, everything is just moving away from ...
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30 views

Big Bang Question

In the early Universe it it's believed that matter and anti-matter annihilated one another till there was but a remaining 1% left. In a matter/anti-matter collision, is there not an explosion of ...
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Entropy was created after inflation?

I'm puzzeled by a statement in Big Bang Cosmology-review about the reheating phase subsequent to the exponential expansion during inflation: In this reheating process, entropy has been created ...
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39 views

Primordial flunctuation gave rise to cosmic structures?

I'm not a physicist, not even a physics student. I'm just reading Lawrence Krauss's book A Universe From Nothing and I got stuck understanding a concept. In his book, Lawrence says: Quantum ...
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1answer
35 views

Experimental evidence for the relic neutrinos

What are the experimental (indirect) evidence for the cosmic neutrino background? Where can I read more about this? The discussion on the wikipedia page about the C$\nu$B seems to me to be more ...
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2answers
112 views

Matter vs. Antimatter shortly after Big Bang

I am not a physicist or astronomer in training at all, so this might be a dumb question with an obvious answer, but as I watched something the other day on matter & anti-matter, and the discussion ...
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125 views

Could there have been two “Big Bangs”?

A couple of years ago, I remember seeing a documentary on the big bang theory. The theory presented was that to explain the cosmic microwave background radiation, there needed to have been two big ...
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381 views

Curiosity episode with Stephen Hawking. The Big-Bang

In an episode of Discovery's Curiosity with host Stephen Hawking, he claims the Big Bang event can be explained from physics alone, and does not require the intervention of a creator. 1) His ...
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205 views

The relation between the speed of light and the Big Bang Theory

I would like to know how much of the Big Bang theory is dependent on the constancy of the speed of light. P.S.: It might be guessed that I am asking this because of the recent CERN news. Yes, of ...
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63 views

Probability of spontaneous Boltzmann brain formation

I was reading through: http://www.scottaaronson.com/papers/giqtm3.pdf But I can't make sense of page 61 discussing Boltzmann brains. Specifically the fact that it says: But the problem is worse. ...
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47 views

Hot Big Bang vs. Big Bang

This should hopefully be a quick one. Is there any difference between the Big Bang Theory and the Hot Big Bang Theory? Around Cambridge I hear everyone using "Hot Big Bang Theory", for example ther ...
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How can I read density fluctuation from microwaves?

The Cosmic Microwave Background Radiation shows temperature differences. The red and yellow areas are warmer. The green and blue areas are cooler. For example consider this picture of CMBR ...
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108 views

How to reconcile these two principles?

Quantum mechanics says that the entropy of an unobserved system remains constant. As such, the apparent growth of entropy is a subjective illusion. If we consider the wave function of the universe, ...
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321 views

Is it possible for dark matter to somehow turn into regular matter?

Is it possible for dark matter to create the regular matter that we, the stars, and the galaxies are made of? The reason I'm asking this is because I have a hard time imagining how something can ...
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403 views

Entropy and Big Bang aren't mutually exclusible? [closed]

There are some principles in entropy im having trouble understanding. If Entropy requires that the energy in the universe must always been constant, shouldnt in theory 'Heat Death' have occurred since ...
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237 views

Primordial Black Hole Detection

There's ample direct evidence for the existence of galactic and stellar mass black holes. However, there is no such direct evidence of primordial black holes, those formed after the Big Bang. A recent ...
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1answer
511 views

How to calculate the density of relic neutrinos?

May be not neutrinos, but antineutrinos? Or both types? In the last case, why they didn't annihilate and what is the ratio of relic neutrinos to relic antineutrinos? Is that ratio somehow related to ...
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175 views

Equation for Hubble Value as a function of time

I am trying to write the equation for the situation where the Hubble parameter $H$ would be changing over time. In other words, it would represent an accelerated expansion of the Universe. That is, ...
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444 views

Superluminal expansion of the early universe how is this possible?

Is this a postulate? I get the expansion of the universe, the addition of discrete bits of space time between me and a distant galaxy, until very distant parts of the universe are moving relative to ...
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656 views

Particles entangled after the big bang

Is that true that the big bang caused the quantum entanglement of all the particles of the universe so every particle is entangled to each other particle of the universe?
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817 views

Is it possible that the Big Bang was caused by virtual particle creation?

As far as I understand, it is understood that throughout the universe there exists, what is known as, a quantum field from which, due to its fluctuations, temporary (pairs of) virtual particles ...
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223 views

Bathroom photons from the edge at the universe [duplicate]

I was looking through my bathroom window this night and I was wondering if any of the photons my retina is hit with are from 13 (40) billion light years away ?! I was looking through it a few ...
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267 views

How can the big bang occur mathematically?

As we know time began with the big bang. Before that there was no time, no laws, nothing. Mathematically how can an event take place when no time passes by? How did the big bang took place when there ...
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819 views

Branes Collision -> Big Bang

Imagine universe occurred when two parallel branes collided, Momentum of Branes converted to big bang kinetic energy after Collision. Thus, high-energy quanta are high-Vibrating strings. what ...
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600 views

Has Cosmological Natural Selection been disproved?

I've been reading Lee Smolin's Life of the Cosmos. Great book and it makes a lot of sense that the conditions in black holes are the same as conditions at the big bang. Question is, has his theory ...
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91 views

What is the age of universe? [closed]

As we know at the time of big bang as mentioned by the scientist the universe expanded faster than the speed of light. So does it mean that at that time all the particles present travelled in the time ...
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453 views

spacetime expansion and universe expansion?

First of all, does the expansion of spacetime solely cause the expansion of universe? Secondly, if spacetime is the sole cause, do objects(matter with mass) themselves expand? Thirdly, by spacetime ...
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128 views

Assuming space is infinite can our observable universe be an island amongst an archipelego?

According to recent measurements our observable universe is roughly 93 billion light years in diameter; also it appears (according to WMAP measurements) that spacetime is flat. Supposing space is ...
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244 views

Do laws of thermodynamics have a place in Theory of Everything? [closed]

I am having a difficulty understanding why second law of thermodynamics is still a valid universally accepted concept. I understand it works on paper for describing isolated heat systems. However, I ...
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255 views

Can cosmic inflation be explained by matter antimatter reactions?

The big bang theory proposes that equal amounts of matter and antimatter were created in the beginning. Shortly afterwards most of it annihilated. Could that have produced enough energy to drive ...
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327 views

How is it possible that we see light from shortly after the big bang?

How can astronomers see light from shortly after the big bang? How did we get "here" before the light that emanated from our "creation"?
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1answer
45 views

Black holes attracting each other [closed]

I was watching the tv series called, through the wormhole, and they mentioned a theory about multiple universes that are separated by a very small distance, like parallel membranes. They mentioned ...
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1answer
54 views

Connection between the Big Bang and Black Holes [closed]

So... this is my first question here after a little while of lurking; so be gentle. I've been thinking lately about trying to wrap my head around the concept of spacetime and how it can be affected ...
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88 views

Time dilation at the Big Bang

At the time the Big Bang happened the matter had enormous density. According the GR (I may be wrong here) such density dilates time. If so, could it be that the time periods just after Big Bang which ...