Big bang Definition and 916 Threads

It is postulated that there was a "Dark Age" subsequent to the so called Big Bang. The "matter" subsequent to the Big Bang would be composed of Quarks,if there was no light postulated for that time. This would indicate that the forces present would be only the Strong Force. The Strong Force of...

Homework Statement According to the standard assumptions, there are three species of (massless) neutrinos. In the temperature range of 1MeV < T < 100MeV, the density of the universe is believed to have been dominated by the black-body radiation of photons, electron-positron pairs, and three...

I don't know this question makes sense or not but; Respect to the two possible size universe models (finite and infinite) how would be the evolution of the universe without the cosmic inflation?

Greg Bernhardt submitted a new PF Insights post Intro to Big Bang and Infinity Concepts Continue reading the Original PF Insights Post.

As I understand it the big head scratcher regarding the BB is how did it get set in motion? How about the notion that regarding our universe, it didn't expand from an inert pinpoint but is instead a breach in the "wall" of an even larger system - i.e. essentially like a volcanic eruption. Of...

- I never quite understood , while people generally believe they must search for the reason of matter, anti-matter unbalance. I mean the big-bang was a violation of the energy conservation law. As far as I understand in the first moment there was only energy which later condensed into matter and...

Hi, did the energy of the universe, right before big bang equal to zero? And if so, does zero as zero-point energy in relativistic theory and quantum mechanics make any sense? If this is not possible, are there any models, including the standard model, SUSY or QFT which consider ground state...

As I understand it, time runs backwards inside a black hole. If the universe were far denser than a black hole when the universe was a fraction of a second old, then how did physical processes ever move forward? That is, how can a clock advance in something as dense as the initial universe?

If the universe suffered a false vacuum decay, would this change physical laws? Could it change the universe so much that it would allow our universe to be a multiverse of level 1, 2, 3 and 4? https://en.wikipedia.org/wiki/Multiverse

A new paper is proposing a new alternative to the Big Bang. His model includes a concept known as bouncing cosmology. https://www.space.com/38982-no-big-bang-bouncing-cosmology-theory.html

My understanding is that gravitational waves have not been detected from the proposed inflationary epoch of the big bang, only from the merger of two super massive objects. Is that correct? Are GWs predicted from the big bang in models where there is no inflationary epoch? If GWs are detected...

So if we summed up all the gravitational force acting on everything (planets stars etc) would the final end point for everything be the location of the big bang? Or does this make no sense due to space bending?

If we discovered that physical laws could not have been otherwise in our universe as a result of the big bang multiverse ideas would be dead "nature could not have been otherwise, and with a fundamental theory we will be able to prove this" If this was true, would exist any possible way of...

I understand that there are roughly ##N=10^{79}## nucleons in the visible Universe. This number comes from adding up the nucleons of ##100## billion stars in ##100## billion galaxies in the visible Universe i.e. $$N=\frac{10^{30}}{10^{-27}}. 10^{11}.10^{11}=10^{79}$$ where mass of sun is...

Greeting Everyone, My name is Bruce Zerr. I have a B.S. degree in Chemical Engineering. I just completed (May, 2017) my second degree in B.S. Business Administration - Finance. I love talking/explaining the Thermodynamics of the Forced Vortex - as it applies to: 1) the Vortex Tube, 2)...

There is a series of documentaries from professor Hawking and his colleagues. Hope you enjoy it.

If a Big Bounce can occur "after a universal singularity is reached or a repulsive quantum force causes re-expansion" then what differentiates it from oscillatory/cyclic models if both of them defend that the universe will re-expand from a singularity or before that...

Hello. I mean no challenge against current existing theories. I wanted to ask, how does the Big Bang model explain the creation of all the existing matter in the Universe? I read that the BB created matter but how how could matter be created? I think it should have been either infinitely...

---I am not sure in which section i should post this question , so if it is wrong section kindly move it to the proper section ---- I am really confused to draw a clear line between what is science and what is not . I know science has some characteristics which differentiates it from...

Does it?

A lot of people talk about the big bang, saying it created something from nothing - it is even used against the big bang. People say "it is impossible to create something from nothing." However, to my understanding, the big bang never created something from nothing. I have read it in many book...

What if we weren't the only big bang that happened in our universe? I don't know much about quantum physics and I won't claim to be anything more than someone who enjoys making queries. However, when I think about the big bang, being the explosion that brought us into existence, I can't help but...

I'm assuming for some time after the Big Bang we may have been close enough to another universe to observe it. Would all signature of such observation be lost due to the heat in the early universe or the length of time past? Could anything observed be a remnant of this?

The ubiquity of the big bang holds no matter how big the universe is or even whether it is finite or infinite in size. How are we so confident that the part of the universe that is unobservable also falls under the Big Bang model?

True or False? A clear answer would clear up years of confusion. Thank you. Edit: I mean observable universe, obviously. I always thought the Big Bang model somehow also accounts for the part of the universe beyond the observable limit, since it is always advertised as the beginning of "the"...

I am wondering, if the big bang was an explosion how can it be that all of the space and time was created simultaneous. Because an explosion have a center, but everywhere is the center of the universe.

In compression of information, once any patterns have been 'condensed' as much as is possible, the information appears entirely random. Any further compression produces loss of information and the quantity of information required to encode it is increased. In one theory it is supposed that all...

Suppose the initial force and energy bursting out during big bang was very huge . The matter just after big bang would have been very close , so the gravitational attraction would have been very high , which would have caused the acceleration produced by big bang to decrease . As time increased...

I just want to verify from physicists whether what I have read in this article is true: http://www.astro.ucla.edu/~wright/infpoint.html It says: The Universe was not concentrated into a point at the time of the Big Bang. But the observable Universe was concentrated into a point

My question is very simple but it is something I have been thinking about for some time. Every time a person needs to have the expansion of the Universe explained or the question "What does the Universe expand into?", people who know a bit about the topic answer that it expands into and onto...

My apologies if there are some related discussions on this topic in another thread here, but I could not find one specifically addressing this question. Big bang theory, as it currently stands, talks of some extraordinarily precise time measurements; you see numbers like that 10^-37 sec...

We all know BigBang theory, which states that the universe is continuously expanding, my doubt is the term expanding, does it mean the expansion of galaxies as a whole or including the planets in it?.

Homework Statement Use Friedmann equations to show that if ##\dot{a} > 0##, ##k<0## and ##\rho>0## then there exists a ##t*## in the past where ##a(t*)=0## Homework Equations [/B] Friedmann : ##(\frac{\dot{a}}{a})^2=\frac{8\pi G}{3}\rho-\frac{k}{a^2}##The Attempt at a Solution [/B]...

What is nucleation and how it works? In cosmology, which is the relationship that nucleation have with quantum tunneling, vacuums and Big Bang?

I have been looking online and in other resources for some answers to no avail. Thought I would sign up on astrophysics forums to find the answer.What is the evidence and data for the period before the cosmic microwave background (CMB) in the early universe? In other words, is the idea of energy...

I read somewhere here (but couldn't find the exact message) where it was mentioned the size of spacetime during the Big Bang is the same size as it is now. But the metric expands. However semantically even though the metric expands, spacetime doesn't expand. But spacetime should get bigger now...

In wikipedia says that in a big amount of time quantum tunneling can create a new Big Bang. EXACTLY, how this happens. https://en.wikipedia.org/wiki/Future_of_an_expanding_universe ("Beyond" part) *note: I'm in high school, but feel free to explain this with complicate process.

The following is from https://en.wikipedia.org/wiki/Big_Bang_nucleosynthesis The era began at temperatures of around 10 MeV (116 gigakelvin) and ended at temperatures below 100 keV (1.16 gigakelvin). The corresponding time interval was from a few tenths of a second to up to 103 seconds. The...

Was the concept of a White Hole ever intended to as a POSSIBLE explanation for the Big Bang, inflation and dark energy expansion of the Universe? Or is it considered crack pottery by the cosmology community? I presume the observable Universe would need to be as small as say a single atom in...

When, as a layman, I read or hear about the Big Bang, it generally comes to the same issues: massive release of energy, very high temperatures, very fast expansion, questions about what came before the Big Bang and so on. Yet, there are some issues that, at least to me, appear to be left aside...

another philosphical Q. i make notion that from what we have learned over the life of humans, is that we don't know too much, and for some things we were just wrong. i ponder this Q, why do we write The Big Bang at time=0 as a very small point that contains all the mass of the universe. can't...

"Before the big bang, scientists believe, the entire vastness of the observable universe, including all of its matter and radiation, was compressed into a hot, dense mass just a few millimeters across." Isn't this describing what the singularity of a black hole is? Black holes spin extremely...

Is it fair to think about the statement "the big bang happened everywhere at once." as meaning the singularity that spawned the "big bang" was very large by cosmic scales, even infinitely large? (I am aware that the word "singularity" refers to a place where the math breaks down and not a point...

Did the universe Absolutely begin?

Any pointers about where to get information and perhaps pictures of the different whiteboards shown in Big Bang Theory? I am particularly interested on the season where Sheldon abandons string theory; the boards for this chapter (155, season 7 ep 20, aired 10th April 2014) seem to show some...

In a discussion with a friend I am unable to explain to him why at this moment we still can detect cosmic background radiation. According to his reasoning the radiation that originated from the big bang should have passed us long ago. Where in fact does this radiation that we now detect come...

Homework Statement the relative concentration by mass of helium at 3 minutes after the big bang is 2-5 parts per 100,000. If you had 1 kilogram of the normal matter from the universe at a time 3 minutes after the big bang, how much of it would be normal helium nuclei? Homework EquationsThe...

I've never been able to visualize the big bang and my hubris is now leading me to believe it must be impossible. A line in "A Universe from Nothing" talks about how if you look far enough away, since you're looking into the past, you could theoretically see the big bang. I get that; I just can't...

The sound horizon is the distance that a wave of plasma can move from the end of Inflation to Recombination (roughly 300,000 years). In several papers and talks, this is described as a moving wave (see https://www.youtube.com/watch?v=JSqIBRbQmb0 at the 23 minute mark). The velocity of the wave...

If it is not know what happened in the first fraction of a second after the big bang, how is it know that it was really only a fraction of a second?