A single question re Big Bang Theory.

[xelasnave]

I find it difficult to determine what the Big Bang Theory says given there are many opinions that do not seem to reflect the science.

It is my understanding that the theory deals only with the evolution of the Universe after a certain point and deals with that evolution from " a hot dense state" to the current Universe.

I note that it is my understanding that the theory does not say that the Universe was formed from nothing and this aspect seems like unsupported speculation...is my view correct?

However my question is this, (in light of the Hubble and James Web images I wonder about stuff)...does the theory tell us that all we can observe ( presumably a sphere some 93 billion light years diameter) was all at a point in time an infinitely small point that was initially referred to as the " primordial atom" and also " the singularity" ... is the proposition that all we see, notably what we see in the various images, all part of the initial "singularity" or "primordial atom"....

Alex

[JohnF (John)]

A professor of Astrophysics from Princeton University, plus another one from Corwell University [I do have there names in a book at home -- no internet or mobile phone at home] claimed that Magnetism is the major problem with that Big Bang theory.

Also I picked up a freeby 'NEW SCIENTIST' MAGAZINE. It had an article talking of problems in AstroPhysics. It did mention that a cluster of Galaxies thought to be the same distance away from Earth show very different Red Shifts. It also talked about evidence that the speed of light is decreasing. Certainly our earth's Magnetic field is rapidly decreasing.

[Atmos (Colin)]

The latest theory I read (which was a few years ago) was that the Big Bang Theory had the universe starting the size of a watermelon before going through it's great expansion where it increase in volume some crazy amount in some fraction of a fraction of a nanosecond before slowing down to the speed at which it is expanding today.

[xelasnave]

Originally Posted by JohnF

A professor of Astrophysics from Princeton University, plus another one from Corwell University [I do have there names in a book at home -- no internet or mobile phone at home] claimed that Magnetism is the major problem with that Big Bang theory.

Also I picked up a freeby 'NEW SCIENTIST' MAGAZINE. It had an article talking of problems in AstroPhysics. It did mention that a cluster of Galaxies thought to be the same distance away from Earth show very different Red Shifts. It also talked about evidence that the speed of light is decreasing. Certainly our earth's Magnetic field is rapidly decreasing.

Hi John

I do hope you are well.

I am not interested in finding problems with the in Bang Theory I merely want to establish what it says and does not say.

I find it difficult enough to learn the mainstream position and even when reasonably educated really don't think finding flaws is of any help...I subscribe to the notion that if one has a better theory then present it taking into the account of the requirements a new theory must cover.....it is a very big job and one that I do not plan wasting my time upon.

I like to think I can look at something and not be driven to form an opinion.


Thank you for your input.

Alex

[AdamJL]

Hi Alex

At the moment, we can't see back that far. JWST can see very far back into time, but only after the universe cooled and matter formed. We can see the afterglow of the plasma of course (CMBR) but that's it so far.
Why can't we see that far? Because there's a giant wall of plasma (i.e. no matter) between us and the "event". We can only theorise what was before the formation of matter and the CMBR helps a lot, but we can't actually see beyond that.

One area where the standard model breaks down is anywhere near infinity.. that is, a black hole or the birth of the universe. Whenever we see something "infinite" then it's usually a warning that something's wrong with the science.

[oska (John)]

Alex, I think your understanding is correct.
The maths, worked backwards gives the theoretical notion of a singularity.
As to your question: In reality the bottom line is we don't (perhaps can't) know and are merely speculating as to the state(s) at the early time scales. And the level of speculation goes up (perhaps exponentially) as time t approaches the theoretical singularity.
In my opinion terms like "primordial atom" are designed to provoke emotions.

[xelasnave]

Originally Posted by Atmos

The latest theory I read (which was a few years ago) was that the Big Bang Theory had the universe starting the size of a watermelon before going through it's great expansion where it increase in volume some crazy amount in some fraction of a fraction of a nanosecond before slowing down to the speed at which it is expanding today.

Hi Colin nice to have your input but I expected you to be the man with some very solid specifics...


The " understanding" I have is that the Universe started at the size of an atom ( without being very specific... even a big one will do I guess), it then experienced a period referred to as " inflation" where the size went from the size of the atom to the size of a basket ball in, and here I quote Neil Dr Grasse Tyson..."in a zillionth of a zillionth of a zillionth of a second" and thereafter expanded at more or less the current rate although there is a paper that tells us the rate of expansion is speeding up....

As I understand things the Big Bang Theory was in peril of being discarded until the Theory of Inflation was presented by Mr Allan Guth...when..I don't recall...which was basically a math fix concluding the inflation could occur by a rapid doubling but as far as I am aware there was no observation that offerred any basis. I can only assume that my ignorance hides from me stuff that would make the proposition seem more reasonable.

I guess what is going on in my head after looking at the various images we are now very lucky to have is..."How the heck could you extrapolate the observed expansion of the Universe such that the proposal has billions of gallaxies rewond to fit in the volume of an atom...or even a watermelon".... At the time of the floating of the Big Bang Theory the entire Universe was considered to consist of the Milky Way so squeezing that back down somehow seemed doable but we now know the observable Universe is billions of times bigger..that is the observable Universe..that which we can somehow " observe" add in what is past the limits of our observation can't be done as we have no idea...although I have read one model suggests 250 times and others say infinite...does anyone other than me wonder how it Al came down to an atom or watermelon size?.

My poor little brain can't accept that such could be possible and I know the idea is there is heaps of "emptyiness" in an atom even taking into account the electrons and nucleus...

My thoughts would be that past the CBR the theory is unsupported speculation...

Thanks again I hope all is good in your world.

Alex

[xelasnave]

Originally Posted by AdamJL

Hi Alex

At the moment, we can't see back that far. JWST can see very far back into time, but only after the universe cooled and matter formed. We can see the afterglow of the plasma of course (CMBR) but that's it so far.
Why can't we see that far? Because there's a giant wall of plasma (i.e. no matter) between us and the "event". We can only theorise what was before the formation of matter and the CMBR helps a lot, but we can't actually see beyond that.

One area where the standard model breaks down is anywhere near infinity.. that is, a black hole or the birth of the universe. Whenever we see something "infinite" then it's usually a warning that something's wrong with the science.

Thank you for your input Adam.

And I tend to agree with your approach...it's like the use of "dark" ...when you see "dark" I think it is a declaration that everything there after ais s entire speculation...dark matter for example...why someone just does not declare the obvious..."if we use our current sums we create so much hidden matter that the prospect would seem unreasonable".

It is my unsupported belief that gravity is not a force of attraction or best described as the bending of space but a universal pressure created perhaps by the pressure of radiation, or the pressure from nutrinoes but if you think of gravity being external then the unexpected rotation curves of gallaxies seem reasonable and what one would expect if gravity is indeed a universal pressure...

Anyways we are only a century into cosmology and I expect things will change over time...

Thanks again.

Alex

[xelasnave]

Originally Posted by oska

Alex, I think your understanding is correct.
The maths, worked backwards gives the theoretical notion of a singularity.
As to your question: In reality the bottom line is we don't (perhaps can't) know and are merely speculating as to the state(s) at the early time scales. And the level of speculation goes up (perhaps exponentially) as time t approaches the theoretical singularity.
In my opinion terms like "primordial atom" are designed to provoke emotions.

Thanks John for sharing your wisdom.

The primordial atom was a key term when the Therory was being developed and seems to have been sparked by many cultures having their cosmology starting with a " cosmic egg"...which was in general a Pagan notion but the notion seemed to appeal and so reinvented as the "cosmic atom".

Having time on my hands I tend to think about these things... I am more inclined to think the Universe is eternal and has always been here rather than coming from a super hot dense state but what I think is irrelevant and please realise I make no claim that I have the answers...the method of extrapolating things back to a dot seems entirely flawed to me.

Still I am not a crack pot as I respect current theories and scientific method...

I do wish that I had the ability to program so I could create a universe with universal pressure operative and then put things in like a galaxy to observe the rotation curves...

Alex

[Atmos (Colin)]

Adam has pretty much hit the nail on the head. We can see back to ~ 380,000 years after the Big Bang, before that time every atom in the universe lived in a plasma which was virtually homogenous and isotropic except for some very minor fluctuations which are visible in the CMB as the warmer and cooler patches.

There is no real evidence for anything before the CMB. We know the universe had a beginning and if we use the cosmological constant as reverse back from the size of the universe as far back as we can see we know roughly when it began... As long as the universal constant was actually constant during that period. Much of this hinges on whether we are an open, closed or flat universe. Currently we are considered as "flat" meaning that the cosmological constant is actually constant. In an "open" universe the Hubble Constant was slower in the past and continues to increase in speed over time. In a "closed" universe you could say that it'll eventually reverse direction and we'll have the Big Crunch! That's probably the most exciting of the theories as it means that the universe restarts every few trillion years.

The universe starting as a dot in the most logical if you think of the universe as "flat" as it started somewhere at some point and expanded from there. Much like what happens behind the event horizon of a black hole, we don't actually know what happens when we compress matter excessively. A black hole to us is really just the event horizon, a point where the gravitational well of space time is steeper than the speed of light. As for what happens in the cosmic soup before the universe became visible? Lets peer into a black hole and see :wink:

[Wussell (Russell)]

I thought nothing could travel faster than the speed of light, but it appears that the universe expanded much faster than the speed of light

[AdamJL]

Originally Posted by Wussell

I thought nothing could travel faster than the speed of light, but it appears that the universe expanded much faster than the speed of light

Nothing can move faster than C (which really should be called the universal speed limit not necessarily the “speed of light” IMO, because other things move as fast as light, and yes I’m nitpicking!) in space, but space itself does not have that rule.

[xelasnave]

Thanks to everyone...I like it that here there is recognition that the CBR is somewhat a barrier to actual evidence further back....another question ..at that point in the evolution how big was the universe?

Alex

[Atmos (Colin)]

Originally Posted by Wussell

I thought nothing could travel faster than the speed of light, but it appears that the universe expanded much faster than the speed of light

This is where physics gets a bit whacky, none of the matter actually needs to move faster than light if space itself is being created… if you think of space as actually being a non-physical construct. Enter dark energy!

[xelasnave]

I googled for an answer to my previous question...

Here is one result.


People also ask
How big was the universe when the CMB was emitted?
The Cosmic Microwave Background was emitted when the Universe was about 400000 years old. When this happened, the size of what is visible now was about 1000 times smaller than it is now, or about 100 million light years across.https://www.google.com/url?sa=t&sour...6r_ORnRulE9uIA

[ChrisD (Chris)]

Originally Posted by Atmos

The universe starting as a dot in the most logical if you think of the universe as "flat" as it started somewhere at some point and expanded from there. Much like what happens behind the event horizon of a black hole, we don't actually know what happens when we compress matter excessively. A black hole to us is really just the event horizon, a point where the gravitational well of space time is steeper than the speed of light. As for what happens in the cosmic soup before the universe became visible? Lets peer into a black hole and see :wink:

That's such an interesting comparison.

What's inside a black hole is the subject of debate and research in theoretical physics. It may not be a singularity, all we can say is that you have a given mass inside the Schwarzschild radius (event horizon).

The radius of the event horizon for any given mass black hole, the Schwarzschild radius, can be calculated using r = 2GM/c^2.

So if the Earth became a black hole it would have an event horizon radius of 8.87 millimeters. For the Sun, less than 3km. A black hole the mass of the entire Milky Way would be 11.2 million kilometers, easily inside the orbit of Mercury.

However, the interesting one is the event horizon for a black hole the mass of the entire visible universe. It would have a radius of around 157 billion light years. That's larger than the observable universe, so is it possible our universe is inside a black hole? Is it possible that big bang might have been an expansion of the singularity in the black hole we live in.

Since there is no way to know how matter is arranged inside a black hole or to prove that we live inside one we may never know. But it is possible, and interesting to think about.

Chris

[AdamJL]

Originally Posted by ChrisD

But it is possible, and interesting to think about.

Chris

it certainly is.. Especially if you consider that the vast majority of the universe's life (that we know of) will be the age of the Black Holes. These initial ~13-14bn or so will pale into insignificance against the trillions upon trillions of years that black holes will exist. So if it's possible for a universe to exist within a black hole, it's almost a mathematical certainty that we're in one

Have a watch of this cool vid and try (and fail like we all do!) to understand the timescales involved

https://www.youtube.com/watch?v=uD4izuDMUQA

edit: or there's the holographic principle idea, similar but the not the same as the black hole concept. That it's possible to encode higher dimensions on a lower dimensional surface. So our 3 dimensional spacetime is the projection of a 2 dimensional surface somewhere...
https://www.space.com/black-holes-ho...omputing-study
https://www.scientificamerican.com/a...-anniversary1/
(this idea needs lots more work, but it's cool to think about!)

[Kal (Andrew)]

The speculation that our observable universe is inside of a black hole is the one that I believe is most plausable. It would also mean that black holes within our observable universe that we see would be seperate space-time universes themselves. This theory could also help explain why the expansion of our universe is not constant, as it depends on external factors such as how much energy is absorbed from outside of our observable universe (much like how a black hole can grow when it consumes mass, or lose mass through Hawking radiation)

[xelasnave]

That is interesting.

I need to change the title to this thread because I have another question , I know the answer if course but it is an interesting matter to speculate upon particularly with the universe possibly being inside a black hole...

Is the universe finite or infinite ?



Alex

[croweater (Richard)]

I don't know Alex but given that Hawking says black holes evaporate does that mean that our universe is evaporating into a universe that is evaporating, that is evaporating.........
Cheers, Richard