The big bang still happening?

[too-open-minded]

Here is a concept that I'm really trying to wrap my head around.

 

If the big bang started from a singularity and then just began to expand, with everything in the universe still expanding. How can see still see the cosmic microwave background radiation? Wouldn't it of have dissipated with the universal expansion rather than congregate back to earlier locations of the universe?

 

I'm guessing that I am just misunderstanding something, please help.

[StringJunky]

too-open-minded, on 01 Nov 2013 - 05:03 AM, said:too-open-minded, on 01 Nov 2013 - 05:03 AM, said:too-open-minded, on 01 Nov 2013 - 05:03 AM, said:too-open-minded, on 01 Nov 2013 - 05:03 AM, said:

Here is a concept that I'm really trying to wrap my head around.

 

If the big bang started from a singularity and then just began to expand, with everything in the universe still expanding. How can see still see the cosmic microwave background radiation? Wouldn't it of have dissipated with the universal expansion rather than congregate back to earlier locations of the universe?

 

I'm guessing that I am just misunderstanding something, please help.

The light that was over there, is coming over here and the light that was here, is going over there...it's taken billions of years for those photons to reach us. You might find it easier to visualise if you imagine yourself standing on the surface of a sphere and this sphere's surface is the path the photons travel on. Wherever you are on it, photons from the CMBR will be coming to you.

Edited November 1, 2013 by StringJunky

[Strange]

Here is a concept that I'm really trying to wrap my head around.

 

If the big bang started from a singularity and then just began to expand, with everything in the universe still expanding. How can see still see the cosmic microwave background radiation? Wouldn't it of have dissipated with the universal expansion rather than congregate back to earlier locations of the universe?

 

I'm guessing that I am just misunderstanding something, please help.

 

It is a tricky concept. The important point is the the cosmic microwave background (CMB) radiation was everywhere; it was released when the universe became transparent as it cooled. This is called the "surface of last scattering". Over time we receive radiation from further and further away - simply based on the time it has taken for those photons to reach us.

 

Here is a nice analogy called "the surface of last screaming" which might make it clearer: http://ned.ipac.caltech.edu/level5/March03/Lineweaver/Lineweaver7_2.html

[BusaDave9]

The universe is mostly empty space. Light will travel billions of lightyears without hitting anything. The same can be said of the background radiation. It will travel for ever until it hits something and is absorbed.

[Гера�им]

Expansion of the Universe results in increasing entropy (i.e., cooling) and the eventual end of the Universe is expected to be the Big Freeze, more than 10¹⁵⁰⁰ years from now.

So gloomy. I don't trust. The Universe will extend beacause it develops, it has a matter, which not all is involved.If the matter of vacuum ends, the Universe again will contact and will blow up.

[too-open-minded]

I understand that, but would it be irrational to think that maybe CMBR and whatever first expanded from the singularity is still being emitted from the singularity or where it was? Before photon decoupling, isn't that the light(CMBR) we are looking at?

[Strange]

I understand that, but would it be irrational to think that maybe CMBR and whatever first expanded from the singularity is still being emitted from the singularity or where it was?

 

If that were the case, then wouldn't you expect to see a single, very small source?

 

Although, in a sense it is true, because the radiation does appear to come from where the singularity was (i.e. everywhere).

 

(Although, the singularity, probably, was not a physical "thing".)

[machapungo]

Physicists generally agree that the singularity causing the big bang also caused inflation.

I accept that inflation is the creation of space.

I accept that current black holes are also singularities.

 

I assert that all black holes are currently causing inflation via the creation of space.

I assert that the creation of space is really a transformation of mass into space and that space is a form of energy.

I assert that the "dark energy" spoken of as the reason for the expansion of the universe is really "clear energy" that is commonly called space.

 

I accept that all black holes will eventually evaporate due primarily to the transformation of the energy of mass into the energy of space.

I accept that gravity has infinite range.

 

I assert that after the black holes evaporate the universe will stop expanding but there will still be plenty of mass in existence.

I assert that gravity will begin to accelerate all mass toward a location at the overall center of gravity.

I assert that as all mass continues to increase in velocity the total energy of all space in the universe will be increasingly transformed into kinetic energy.

I assert that this acceleration of mass will continue like a bunch of runaway trains all heading for the same station and will eventually crash and form the mother of all black holes.

I assert that at that instant a big bang will occur and a vast amount of mass will be instantly transformed into space and the rest of the energy will form a very large blob of quark-gluon plasma.

I assert that this process is how the universe experiences an eternal bang crunch cycle and that all energy is conserved and is finite.

I assert that the question of what is outside the universe is best answered by the word "nothing", not even space since space is a form of something called energy.

I assert that "dark matter" is largely, if not totally, composed of the quantum particles that pop into and out of existence throughout all of space and is nothing more than a transformation of energy.

I assert that the concept of the existence of multiple universes is invalid because the range of gravity is infinite. "In the end, there can be only one"

 

That is all I have to say about the big bang. Regards.

[Delta1212]

I understand that, but would it be irrational to think that maybe CMBR and whatever first expanded from the singularity is still being emitted from the singularity or where it was? Before photon decoupling, isn't that the light(CMBR) we are looking at?

We're currently inside the singularity, as is everything else in the universe, or at least inside the space where the singularity used to be. That space has just gotten a bit bigger in the meantime.

[GeeKay]

I would much prefer to call it the Big Boom. The vowel in 'bang' (as in Big Bang) is not really long enough for a process that began some 13.7 billion years ago. . . assuming it did, of course.

[Sharanjeet Singh Mand]

May be big bang its a cycle processes, after some time when the force emitted during big bang will finish or the kinetic will turn fully in potential then universe may again start contracting to the singularity .i know this is some thing new but i feel it make sense because a static universe is a dead universe , untill there is a flow of energy!!!but the question is that how every where is a center of universe(it is probably a obstacle -assumption )but if there is some center the celestials or matter must be denser at center or at edges.if it is that means it will contract if the push of big bang stops (due to imbalanced gravitation, it will choose its center automatically .possibly energy serves as the space or surface to the expansion of matter.

[BusaDave9]

...

if there is some center the celestials or matter must be denser at center or at edges.if it is that means it will contract if the push of big bang stops (due to imbalanced gravitation, it will choose its center automatically .possibly energy serves as the space or surface to the expansion of matter.

 

The big bang happened everywhere. All throughout the universe. The early universe was much more uniform than it is today. Even the singularity was everywhere. That's the hard part to comprehend. The universe expanded. Now we have galaxies with lots of space between. It's the gravity that made the universe go from being very uniform to galaxies and star systems.

[StringJunky]

BusaDave9, on 05 Nov 2013 - 03:05 AM, said:

 

The big bang happened everywhere. All throughout the universe. The early universe was much more uniform than it is today. Even the singularity was everywhere. That's the hard part to comprehend. The universe expanded. Now we have galaxies with lots of space between. It's the gravity that made the universe go from being very uniform to galaxies and star systems.

I think IIRC you missed a step. It is theorised that quantum fluctuations caused the actual deviations or granularity in the initial homogenous universe, which was then amplified by gravity as it inflated...gravity caused the slightly denser gaseous areas to coalesce and ultimately create the galaxies we know today. I just thought it was pertinent to add how the universe went from smooth to irregular.

[too-open-minded]

All the energy in the known universe together in a singularity, I wonder what kind of gravitational proportions that could have had?

 

Did gravity exist before the big bang?

Edited November 5, 2013 by too-open-minded

[imatfaal]

All the energy in the known universe together in a singularity, I wonder what kind of gravitational proportions that could have had?

 

Did gravity exist before the big bang?

 

Before the big bang is difficult and purely hypothetical - but one of the reasons that we search for unification of the 4 forces is that immediately after the big bang we need to use some sort of quantum gravity and I guess that if we need it immediately afterwards then we would probably need a unified theory for before as well(even though before has very little meaning)

[BearOfNH]

[...]I assert that gravity will begin to accelerate all mass toward a location at the overall center of gravity.[...]

 

First you need to assert the universe is convex. If it is not convex, say instead a Torus, then the predicted collapse may not happen the way you envision.

[MigL]

It is fortunate that for you, machapungo, assertions don't have proof or supporting evidence, otherwise I could assert that you don't know what you are talking about.

[too-open-minded]

So before the big bang, what are the most widely accepted views on it?

[Delta1212]

The most widely accepted view is that we have no idea what, if anything, came before the Big Bang.

[pantheory]

So before the big bang, what are the most widely accepted views on it?

 

There are just a few logical possibilities.

 

1) If there was such a thing as the Big Bang and a time before the BB, then the BB was not the beginning of everything.

 

2) If the universe is finite in age it had a beginning time and the word "before" could have no meaning. If the universe is infinite in time, it had no beginning by definition.

 

3) Regardless of the model of the universe chosen it would be logically impossible for the universe to have had a cause if the universe is defined as everthing that exists. A finite universe cannot have had a cause if the word universe means everything. An infinite universe also cannot have had a cause by definition.

 

primary possibilities are:

 

1)The Big Bang was the beginning of everything in the universe.

 

2) We are in a cycling finite or infinite universe involving periods of contraction and expansion.

 

2) There was no BB and the universe may be in a generally unchanging condition. Redshifts would have had a different cause other than an expanding universe. Such a universe may or may not have had a beginning.

 

3) Our universe is just one of many. This is usually considered an infinite universe model since each universe had a cause before itself in a never ending chain or cycle of events.

[too-open-minded]

See this is what I don't understand, the big bang. Implying that there was a beginning, and nothing existed before?

[Strange]

See this is what I don't understand, the big bang. Implying that there was a beginning, and nothing existed before?

 

But the big bang theory doesn't imply that. We can model what happened at earlier and earlier times; the universe was hotter and denser. At some point the conditions become such that we cannot say, with current theories, what happened before then.

 

The "beginning from nothing" idea is just a bad extrapolation beyond where the data is valid.

[pantheory]

.... this is what I don't understand, the big bang. Implying that there was a beginning, and nothing existed before?

 

 

From my posting #45, you realize that either the known universe had a beginning and has existed for a finite time period, or that the observable universe is infinite concerning past time. If the universe is really expanding then it is theoretically believed to be expanding from a single point or from a small finite hot dense volume.

 

This theory could be wrong but it does not violate logic. Something from nothing is really not a real proposal of the Big Bang model. Instead theorists like Hawking have proposed that the beginning could have come from the Zero Point Field. This field is full of energy so it is very different from "something from nothing.." The Zero Point Field origin for the universe, although it may be presently popular, it is not the mainstream version of the BB model, nor is a multi-verse version of it a consensus hypothesis.

Edited November 16, 2013 by pantheory

[magma time light]

Is there only one universe?

[BearOfNH]

Is there only one universe?

Nobody knows for sure. Hawking thinks there are a lot of universes, but doesn't have (nor claims to have) any proof.

 

It's also a matter of definition. Where one physicist says there are many universes, another may claim those are all "sub-universes" and there's only one "universe" that contains them all. One man's meat is another man's poison...