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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Did spacetime curve infinitely about 13.7 billion years ago? [duplicate]

GR/Big Bang Model implies that there was a singularity about 13 billion years ago, in which all the matter and energy along with the observable universe (or perhaps, the entire universe) was ...
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62 views

The infinitely dense point from which the universe allegedly originated - the universe must expand, right?

This is all based on some thoughts this article gave me. Assertions The big bang theory is currently accepted theory about the origin of the universe Infinitely dense implies some kind of material ...
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218 views

How could the “Big Bang” singularity have actually expanded? [duplicate]

We have mountains of evidence about singularities and how they work, and we have mountains of evidence that the "Big Bang" was the origin of the universe as we know it. But if compressing enough ...
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How come some people are claiming that the Big Bang never happened?

A news story is going viral on social media networks claiming that two physicists have found a way to eliminate the Big Bang singularity, or in layman's terms (as claimed by many sensationalist news ...
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4answers
971 views

Why do we theorize that the Big Bang created space? [duplicate]

I just asked this astronomy question about how far away the light is that would show us the beginning of time, the Big Bang. Some answers claim that the light I ask about doesn't exist, because "The ...
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354 views

Is there an exact formal definition of the Universe?

I've read several articles about Observable universe, Universe and Hubble volume, including Wikipedia articles and other references. After this I wondered: Is there a formal, rigorous definition in ...
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101 views

Did the Earth (amongst other things) travel faster than light?

It's often said that when you look far across space with a telescope you are looking back in time, as the light has only just reached our position in space. However, given that the Earth and many ...
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1answer
119 views

Did light already experience death of the universe immediately after the Big Bang?

Let's suppose that I am on Point A with a light-beam launcher. My goal is to launch a beam of light to Point B, which is about 8,000 quadrillion light years away. My friend named Jack is at Point B ...
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Is it possible for the universe to be moving towards something, rather than expanding?

We all know that the universe is flying away from the Big Bang at speeds approaching or exceeding the S.O.L. However, is it physically possible for an object to be pulling the universe away as well?
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60 views

Big bang theory

How much energy and heat were produced by the big bang? I'm reading Bill Bryson's Short history.... He mentioned a point that to forage light elements like hydrogen, helium and lithium into elements ...
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38 views

Would the universe look any different today if energy/matter had not appeared until some time after spacetime had begun expanding?

Why is it necessary for spacetime and energy/matter to begin together at spacetime = 0? Would the universe look any different today if energy/matter had appeared some time after spacetime had begun ...
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166 views

Theory of black holes producing matter or antimatter [closed]

One of my friends gave a theory about the formation of black holes. He said that: Black holes are formed when an extremely massive star collapses in its own gravity to produce a particle of ...
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Was everything in the Universe “created” from light?

Is the following true? The only matter existing directly after the big bang was electromagnetic radiation.
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251 views

Expanding universe - Creation of Space [duplicate]

Is the expansion of the space between the galaxies caused by stretching of existing space or the creation of new space? The fact that the energy content remains constant, and is therefore not being ...
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193 views

Is entropy absolute (as in absolute temperature)?

Following this question on the Entropy at the Big Bang where I asked: Since Entropy always increases (in general); its expected that the entropy at the beginning of the universe should be the ...
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15 views

Does the density of matter increase as we approach the big bang? [duplicate]

I am interested in knowing whether it is clear (undisputed) that the density of matter/energy increases as we approach the time of the big bang? Does this follow from the FLRW metric?
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What was the entropy of the universe at the time of the Big Bang?

(I asked this question in Philosophy.SE; but I was advised to direct it here, despite it is, in my opinion, somewhat too speculative for physics.SE). High entropy generally means high disorder; and ...
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98 views

The Big Bang theory [duplicate]

According to big bang theory the whole universe was formed by this big explosion and it gets bigger and bigger Does that mean it has limits? and what do you think we can found beyond all that ?
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56 views

How Do we Know How Old the Universe Is? [duplicate]

It is common knowledge that the universe is 13.8 ± 0.037 billion years - but how was this calculated?
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1answer
896 views

The mass of universe at the point of the Big Bang

The density of universe at the time of the Big-Bang was infinitely high. Does that mean that the mass was also infinitely high? ( the universe was extremely small at that time)
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353 views

How is the Horizon Problem really a problem?

I always thought the uniformity in the temperature of the CMB was supposed to be expected, since it's a much more probable initial condition for the universe. I finally found someone explaining what I ...
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519 views

How does inflation relate to spontaneous matter creation?

According to Inflation for Beginners, ... quantum physics allows the entire Universe to appear, in this supercompact form, out of nothing at all, as a cosmic free lunch. The idea that the Universe ...
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1answer
170 views

Why did the big bang explode if there is no oxygen in space? [duplicate]

If there is no oxygen in space, where the super dense singular object was suspended, then why did it explode because this reaction needs oxygen?
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4answers
805 views

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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2answers
214 views

What is the origin of CMB fluctuations?

I have read somewhere that CMB (cosmic microwave background radiation) fluctuations in temperature are linked to mass distribution fluctuations in the early universe (at ~350000 years after Big Bang, ...
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74 views

What force made the big bang erupt?

Might be a stupid question, but it has been bugging me for a week. Pre big bang conditions look like an universe mass black hole to me, so what force acted against the massive gravity at the ...
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171 views

Infinite Universe and Big Bang

A common view now in the physics community is that the Universe is infinite in extent (which makes Hubble sphere an infinitely small part of the Universe). On the other hand, there is the Big Bang ...
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58 views

Light speed after the Big Bang

We know that immediately after the Big Bang space was opaque to light. As space expanded, light could travel. However I would think that as space expanded at some de sites the light would be much ...
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Quantum Wavefunctions Without Space

A handful of physicists have a rather peculiar definition of 'nothing' in terms of cosmology. Their claim is that the Universe, assuming it has 0 total energy, could have arisen from nothing but ...
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190 views

Is the big bang a fact? [duplicate]

I have watched many physics debated and in everyone of them, physicists take big bang for granted. But, is the big bang actually proven, or there are many evidence that indicate that it did happen?
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83 views

What (if any) state did energy exist in prior to the big bang? [duplicate]

I am comfortable with the idea that 'pure energy' cannot be observed, only different forms in which it manifests. I can also understand that matter-antimatter interactions result in fundamental ...
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353 views

Was the Big Bang actually cold?

As I understand, from watching the Discovery Channel, the total amount of energy in the universe is zero. As such, people like Hawking explain that the universe can be created out of nothing ...
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618 views

Why isn't our universe symmetric?

Why were random variations introduced in the spherically symmetric universe after Big Bang which made it non-symmetrical. Since the outcome of a coin toss depend on factors such as torque applied, air ...
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614 views

What caused the expansion of the universe to slow down after the inflationary epoch?

As everyone knows, when the big bang happened, the universe expanded at an unbelievable rate and this was called the inflationary epoch (or more popularly cosmological inflation) which lasted for ...
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132 views

Where's all the light going in the universe?

According to my knowledge, matter can not go faster than light, and light is emitted constantly in the universe from many types of reactions. If this is so, then isn't light constantly getting past ...
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What prevented the early universe to become a black hole before inflation? [duplicate]

I am an ignoramus on this subject, and I assume that these statements quoted from wikipedia are more or less accurate:(http://en.wikipedia.org/wiki/Inflaton) 1) Prior to the expansion period, the ...
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Loop quantum gravity- is the critical density sufficient to form a 'black hole'?

I think in loop quantum gravity the rate of expansion of the universe is found from: $H^2=\frac{8\pi G}{3}\rho\left(1-\frac{\rho}{\rho_c}\right)$ And I was wondering whether the critical density ...
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86 views

Why seeing further in “timespace” does not add up?

I've read that astronomers have received a light (a photon) 13 billion years old. Here's my question: If we start to turn the clock backwards all matter, energy, etc should start heading to the ...
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108 views

Center of mass & Big Bang Theory

I have read in my text books about the Big Bang theory and quote "the entire matter in the universe was once concentrated in a single very dense and hot fire ball; it exploded some 20 billion years ...
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Will the background radiation get “dimmer”? If so when will it be “turned off” [duplicate]

This video http://youtu.be/_mZQ-5-KYHw talks about the background radiation which we can observe today. It's from the beginning of the universe and has traveled so long that the expansion of the ...
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1answer
172 views

What would be the first compound formed in the early universe?

This may sound like a chemistry problem, but I suspect this would have lot to do with primordial nucleosynthesis. After all physics underlies everything. It is believed that several elements were ...
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59 views

TEO: raise of a System [closed]

I think this question is settled somewhere betweeen physics and philosophy and we surely can not find a answer that fits 100%, but lets talk about it. While thinking about how the universe and its ...
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1answer
189 views

How can the Big Bang singularity exist in spacetime if it has zero volume? [closed]

How can the Big Bang singularity exist if it has zero volume? I tried googling to find the answer - no help. Can someone give a general idea how can the big bang singularity exist even if it has zero ...
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Why is the graph of CMB/black-body radiation asymptotic?

Speaking of this graph of blackbody radiation, I see that the graph goes to 0 asymptotically: As we go to higher and higher frequencies, the energy of a single photon becomes increasingly high. ...
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Did the Big Bang happen at a point?

TV documentaries invariably show the Big Bang as an exploding ball of fire expanding outwards. Did the Big Bang really explode outwards from a point like this? If not, what did happen?
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562 views

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 ...
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2answers
370 views

How do we know that space expanded with speed faster that a speed of light during big-bang inflation?

How do we know that space expanded faster than a speed of light in inflation? I have read this Phys.SE question, and it says that limit for faster than a speed of light is for matter and waves only. I ...
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3answers
261 views

Has the universe we live in started as a black hole that is imploding?

As discussed in this question, as far back as the 1960s it was suggested that the Schwarzschild metric can be smoothly joined to a de Sitter metric. For example the idea has been used by Lee Smolin in ...
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35 views

Is energy since the big-bang still here in the present?

Based on the concept that energy can never be destroyed and is only transferred. Does it mean that energy since the formation of literally everything still here today?
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Searching for Big Bang Neutrinos

How is it possible to discover neutrinos from the big bang? Were the neutrinos emitted just before the big bang? Or at the same moment? If they moved outward in all directions, basically unhindered ...