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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Is redshift the only way by which we can tell that space is expanding?

There's another question on physics.SE whose answer, if I have understood it correctly, explains that the farther the points are in space the faster they are moving away from each other. Actually, ...
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144 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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293 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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4answers
340 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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22 views

particle horizon and big bang

The farthest radiation we can see is from the particle horizon. But the farthest radiation is the CMB. Why does all radiation from the particle horizon stem from that earliest possible source time? In ...
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126 views

Age of the universe [closed]

Does the fact that the edge of our observable Universe contains information from the beginning of the Universe give us an ability to determine its age? The edge of our observable universe surely has ...
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305 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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228 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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101 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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562 views

How far away is Cosmic Background Radiation? [duplicate]

I've been reading about Cosmic Background Radiation (CMBR) lately. My understanding so far is that this is the "Noise"/"Flash" from the big bang. Assuming that information is correct, how far away ...
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2k views

Did space and time exist before the Big Bang? [duplicate]

I accept the Big Bang theory. What I can't understand is how there can be a where or when to the Big Bang if space time did not exist prior to it. Did space and time exist prior to the Big Bang?
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253 views

In the big crunch theory, when the big crunch singularity forms, can the resulting black hole decay through hawking's radiation?

I've been pondering about this and I couldn't really find the answer for this. The big crunch theory postulates that the universe will eventually stop expanding and reverse back in on its self into a ...
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531 views

If the Big Bang theory suggests that the Universe is “expanding” then what is it expanding INTO? [duplicate]

I am a software engineer and not an astrophysicist but I want to know if anyone is working on sorting out what exists outside the universe? So what about outside spacetime? what is there? or shall I ...
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2k views

List of theories supporting origin of universe [closed]

Big Bang theory is widely accepted theory when it comes to origin of universe. What other really compelling theories are out there explaining/supporting the origin of universe. I know many people ...
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49 views

Is there any situation in which a primordial black hole-sized black hole form AFTER the “Big Bang?”

I have seen that primordial black holes may have formed at the start of the universe due to the density of matter. So, is there any way in which our current Universe could spawn a non-stellar mass ...
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45 views

Can accelerating universe avoid Big Bang?

Expansion of our universe is accelerating. This means that it was expanding less rapidly in the past. Is in accordance with the laws of physics a model of accelerating universe in which the rate of ...
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329 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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84 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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202 views

Is there an absolute center of mass exist in the universe? [duplicate]

By the "absolute center of mass" I mean the center of all the matter that exists in a given moment. My friend asserted that today and it intrigued us very much but since we only have a CS degree and ...
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120 views

The universe appears to have a lower bound in the time dimension, why not an upper bound?

The Big Bang looks like a lower bound to the "size" of the universe in the time dimension. Could it also have an upper bound, some furthest point in time from the Big Bang?
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120 views

Infinite number of universes? Black holes are guilty? [closed]

I was thinking, if the space is infinite, what if there are infinite number of spaces, inside our universe? I mean, everyone knows that black holes exist, but nobody knows what happens when you get ...
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2answers
125 views

Could the universe have evolved WITHOUT the non-determinism of quantum mechanics? [closed]

(I'm going to make a few conjectures here - please answer the question in light of them as if they were true, even though of course they may be overly simplistic or wrong) Assuming that: the ...
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82 views

How has the age of the Universe been derived from the observations made by the Planck mission?

The parameters of $\rm\Lambda CDM$ model have been determined to an amazing high precision from the measurements made by the Planck mission. In particular, the Hubble "constant" (the value of Hubble ...
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103 views

Understanding the cause of the big bang

Ok, as I understand the expansion of the initial singularity was caused by quantum fluctuations like the ones predicted by the Heisenberg Uncertainty Principle. But how can these fluctuations occur ...
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180 views

the nature of the big bang

If space-time expanded together with matter then why do physicist bother extrapolating backwards the expansion back to a point in time? I mean does that really tell us anything? I mean if the speed of ...
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287 views

If nothing can travel faster than speed of light then how the Universe is only 13.7 billion years old? [duplicate]

The light would take 93 billion years to reach the edge of universe but nothing can travel faster than the speed of light not even the big bang?
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99 views

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 ...
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86 views

Is this a possible big-bang scenario? [closed]

Assume an universe with a single black hole that contains all the universe's mass and then let's wait for quite some time. What happens if by Heisenberg's uncertainty principle a virtual ...
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98 views

A well-defined quantum probability in the beginning of the universe?

In mathematics or statistics, a well defined probability requires a large sample space. However, in the beginning of the universe, when the first quantum collapse happened, the sample space contains ...
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138 views

Are there still Big Bang Gravitational effects

If all matter was concentrated at one point before the big bang, I assume that the gravity was at a huge scale. For a long time many believed that the universe would eventually collapse back upon ...
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134 views

Cosmic Background Radiation: How did planets form before the CBR could reach us?

I've understood that the Cosmic Background Radiation(CBR) is an electromagnetic wave that originated from the big bang. However, we now live on a planet which that is also originating from the big ...
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3answers
449 views

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 ...
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571 views

How did the energy/entropy/volume/pressure/temperature relationship exist at the Big Bang and how did it evolve thereafter?

According to the current Big Bang with inflation cosmological model? I was under the mistaken impression that there was very low volume, very high temperature/pressure, very low entropy and the Big ...
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274 views

Are there any theories or suggestions for how the multiverse came into existence?

I've just seen a documentary about the multiverse. This provides an explanation for where the big bang came from. But it leaves me wondering: how did the multiverse come into existence? Because this ...
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337 views

How to concile flat spacetime and big bang?

After reading How do we resolve a flat spacetime and the cosmological principle? I still remain perplex. Please excuse my ignorance and try explaining to me : I thought that basically, when we ...
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43 views

About Time and the Big Bang [duplicate]

In a TV ducumentary, I heard that time started with Big Bang, and it is meaningless to talk of "before". This was given without any further explanation, in the peculiar, irritating style of ...
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70 views

Is there evidence that the universe truly is the entirety of “everything”? [closed]

This is a question that has popped in my head recently. Do we have any verifiable proof that the "known" universe truly is everything that is out there? I'm not talking about the multiverse theory ...
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57 views

What happens if the big bang occurs once again?

according to string theory every universe is a large brane and big bang is a event which takes place when two branes collide with each other. if our universe brane collides with another brane there ...
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61 views

Why did the universe have a low entropy at the big bang?

Sean Carroll, in his book "From Eternity to Here", asks the following question. Why did the universe have a low entropy at the big bang? in John Cramer version of the Wheeler - Feynman absorber ...
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39 views

Can quantum fluctuation happen outside space-time? [duplicate]

So far I know, quantum fluctuations happen inside the vacuum which resides in the space-time. So, can it happen outside space-time? Because, one proposition suggest, big-bang was result of some kind ...
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1answer
137 views

How can the universe by infinite when it has known start and finite time since? [duplicate]

Just watched the 'How Big is the Universe?' TV program and it indicated that the universe is believed to be infinite in size. They used an approach involving measuring the internal angles of ...
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2answers
141 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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0answers
41 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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26 views

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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34 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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136 views

Big Bang, Heat Death, and cause and effect

If the Universe has two 'end points', one being the Big Bang, and the other being heat death, is there anything in the laws of physics which forbid a random fluctuation in the heat death state from ...
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87 views

The gravity waves from the big bang? How can we know?

The latest news says that scientists detected gravitational waves from the Big Bang. My question is how do they know the waves originated in the big bang verses any number of supernovae and or ...
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70 views

According to Penrose, Weyl Tensor=0 is the start/end of the Universe. Must it =0?

If I understand Roger Penrose's theory, as the Universe expands and cools, matter is consumed by black holes. Eventually the black holes collide and evaporate so that there is only energy and the Weyl ...
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2answers
235 views

Initial conditions of the origin of the universe [duplicate]

I'm not quite sure this question fits the format of this site but I try to word it the best I can to comply the rules. The question is simple: How far can we go talking about the origin of the ...
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74 views

Speed of light's relation with the expansion of the universe [duplicate]

If nothing can travel at the speed of light and light cannot escape the universe, then the rate of expansion of the universe should be equal to the speed of light, why it is not?