Author Topic: Help to understand the Big Bang  (Read 7675 times)

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Offline AngraMelo

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Help to understand the Big Bang
« on: February 04, 2019, 03:32:57 pm »
I always thought of the Big Bang as being the beginning of everything. There was nothing. No space, no black emptiness, no energy, no nothing. Just a big nothing that we cant even picture in our minds.
But then I started checking out lectures and written material (that I could understand, given that Im not in the area) and got a bit into the Higg's Boson/field and matter itself.
Now I wonder if I got my interpretation of the Big Bang all wrong. Is the big bang just the creation of matter? I started to imagine just empty space. Thinking of the universe before the big bang as if it was a section of the deadest, emptiest and darkest part of the universe after the big bang. Then, BANG and matter shows up.
Im having a really hard time to interpret the nothingness before the big bang, imagining there was no canvas for matter to exist.
Do we know if before the big bang there was a place for matter to exist? Or that is the very concept of the big bang? As it being the creation of matter and a place for it to exist?
Do scientist refer to the word "universe" as being the place where matter can exist? Or the place where matter travelled through or has the potential of traveling through? Because if it is the first "definition", what prevents the edge of particle that is the furthest on the edge of the universe to be the thing creating the universe? I mean, if the big bang created the space for matter to exist doesnt it mean that it either created the space for matter to exist instantly and infinitely in all directions or the very first particles (or waves, or whatever) that left the big bang and are now the ones defining the boarder of the universe are the ones creating the space for matter to exist as they travel?


 
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Online Ampera

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Re: Help to understand the Big Bang
« Reply #1 on: February 04, 2019, 03:35:21 pm »
I need help understanding The Big Bang Theory too, it's one of the most annoying sitcoms out there.  :-+
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Offline AngraMelo

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Re: Help to understand the Big Bang
« Reply #2 on: February 04, 2019, 03:41:09 pm »
I need help understanding The Big Bang Theory too, it's one of the most annoying sitcoms out there.  :-+
hahahaha I have to confess that I like it!
 

Online Ampera

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Re: Help to understand the Big Bang
« Reply #3 on: February 04, 2019, 03:49:43 pm »
I need help understanding The Big Bang Theory too, it's one of the most annoying sitcoms out there.  :-+
hahahaha I have to confess that I like it!

I used to when I was younger, but now it just seems so stilted.
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Offline ataradov

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Re: Help to understand the Big Bang
« Reply #4 on: February 04, 2019, 07:02:48 pm »
My understanding is that there was no "space" in which matter appeared. The space appeared too during that event. This does not mean that there is nothing outside of our bubble, but it is absolutely non-observable to us, so does not really matter.

So I guess my personal understanding is better described by this:
Quote
As it being the creation of matter and a place for it to exist?
.


And also, TBBT was a good sitcom, but it should have been ended at season 5 or so. Now it is just a routine to extract more easy money.
« Last Edit: February 04, 2019, 07:05:44 pm by ataradov »
Alex
 

Offline apis

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Re: Help to understand the Big Bang
« Reply #5 on: February 04, 2019, 08:43:06 pm »
There is a lot of evidence that indicate that the known universe started with a big bang about 14 billion years ago. What existed before that point in time is anyone's guess. That's all.
 

Offline ataradov

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Re: Help to understand the Big Bang
« Reply #6 on: February 04, 2019, 08:56:34 pm »
What existed before that point in time is anyone's guess. That's all.
That is obvious. What is not too obvious is the behavior of matter during that expansion. Sometimes you see people attach measurements to the very first stages of the expansion. Like how long it took in seconds, and how big was the original "clump" at that stage. But you can only measure this stuff as an outside observer. If you are inside the system and your coordinate system expands as you do the measurement, how do you even do it? 

There must be a good explanation for that, I'm not trying to poke the holes in this theory. But this part is usually glossed over and just accepted. At least in popular literature.
Alex
 

Offline bsudbrink

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Re: Help to understand the Big Bang
« Reply #7 on: February 04, 2019, 09:25:42 pm »
What existed before that point in time is anyone's guess. That's all.
If you are inside the system and your coordinate system expands as you do the measurement, how do you even do it?
I wonder about this one myself.  What if entire civilizations existed and perished during those "first few seconds"?  They might consider our current universe cold, empty, dark and dead.

At the other end of things, I have heard physicists talk about the distant dead future of the universe.  All of the black holes evaporated, just a dead cold diffuse gas of iron atoms with occasional random quantum fluctuations.  What if, in that time, through those random (to our perceptions) fluctuations, there were some, very large, very slow "arrangements" (for lack of a better word) of that "material".  What would things "look" like from their point of view?  What if they tried to create a "colossal" (from our point of view) machine to force a few of those iron atoms together to "briefly" create a small amount of iron metal?  A particle collider like machine.
 

Offline apis

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Re: Help to understand the Big Bang
« Reply #8 on: February 04, 2019, 09:35:12 pm »
You can work backwards to about 10−12 s before "time zero" but before that physics as we know it breaks down and no one really knows what happened before that. You can obviously not go back in time and measure what happened 13 billion years ago but you can take the observation we make today and combine them with the theory we have and work backwards. There is a fair amount of evidence that is consistent with the big bang theory that would be hard to explain otherwise (like the cosmic background radiation). If you simulate what sort of universe you end up with if you begin with a big bang, you end up with a universe that seems to perfectly match the one we observe today (it has precisely the right composition of elements/isotopes for example).
 

Offline ataradov

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Re: Help to understand the Big Bang
« Reply #9 on: February 04, 2019, 09:43:10 pm »
You can work backwards to about 10−12 s before "time zero" but before that physics as we know it breaks down and no one really knows what happened before that.
That is exactly the blank statement repeated everywhere.

How exactly do "seconds" work in that original small and dense universe? When you talk about 10−12 seconds. Is this "modern" second as applied to that "old" world? Is there a strong proof that those seconds make sense as a unit of measurement in the early universe?
Alex
 

Offline apis

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Re: Help to understand the Big Bang
« Reply #10 on: February 04, 2019, 10:32:10 pm »
Seconds are seconds, there is no special "old" or "modern" second. I don't know where that figure comes from exactly, but it's like everything else, it is what the established theories would predict given what we observe today. You would have to ask an astrophysicist to get a better answer I suspect.

I believe it's wrong to say the universe in the past was "smaller", it was more compressed and the energy densities were larger. For example, at one point in time it was so hot that all matter was evaporated like a plasma (which would be opaque and thus provides a wall which em-telescopes can't see through) and that is the wall of matter/energy that produced the cosmic microwave background I believe. We can look back in time through telescope up until that point (em-waves take a long time to travel here so when looking at stars and galaxies we are effectively looking back in time, i.e. distance=time). If you keep compressing things, increasing the energy density, established theory eventually gives nonsensical answers, it's too different from anything we have ever observed. The maths indicate that happens about 10-12 after time zero. Thus what happened before that point can't really be answered using the current best theories. There is no doubt very big uncertainty to such estimates though. As someone said in another thread, all physical quantities comes with an uncertainty attached. Maybe 10-100 is a less impressive estimate if it has an associated +/- 10100 s of uncertainty?
« Last Edit: February 04, 2019, 10:33:41 pm by apis »
 

Offline timelessbeing

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Re: Help to understand the Big Bang
« Reply #11 on: February 04, 2019, 10:41:13 pm »
It is my understanding that space-time itself is expanding. (Hence the red shift of the CMB).

What is our universe expanding into? We don't know. There are theories such as multiverse.
 

Offline timelessbeing

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Re: Help to understand the Big Bang
« Reply #12 on: February 04, 2019, 10:43:01 pm »
What if entire civilizations existed and perished during those "first few seconds"?
The universe was just a very homogeneous soup. Not enough complexity for anything to exist. Not even molecules.
 

Offline apis

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Re: Help to understand the Big Bang
« Reply #13 on: February 04, 2019, 10:49:17 pm »
It is my understanding that space-time itself is expanding. (Hence the red shift of the CMB).

What is our universe expanding into? We don't know. There are theories such as multiverse.
Not sure it makes sense to say it's expanding into something even, anything "outside" of the universe is just pure speculation, just as anything that would have happened before big bang. Not because there wasn't/isn't anything, it's just that our current theories gives no information about it.
 

Offline sleemanj

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Re: Help to understand the Big Bang
« Reply #14 on: February 04, 2019, 10:58:02 pm »
If we accept that time "began" at the big bang, without time there is no before.

"At some point in the distant past, all matter and time existed, for reasons unknown, as a single point, something happened and that single point exploded decompressing initially quickly and at an ever decreasing rate, into matter and time comprising the universe."

Can we as humans comprehend more than that?  I suspect not.  Even that is hard.  Imagine nothingness.  No you're imagining an empty space, that's not nothingness, imagine nothingness, no you're still thinking of a bigger empty space aren't you, imaging nothing, nope you're still thinking of a universe with nothing in it, imagine nothing... humans are conditioned to think about things, not nothings, "before the big bang" was nothing.
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Offline apis

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Re: Help to understand the Big Bang
« Reply #15 on: February 04, 2019, 11:17:26 pm »
If we accept that time "began" at the big bang, without time there is no before.

"At some point in the distant past, all matter and time existed, for reasons unknown, as a single point, something happened and that single point exploded decompressing initially quickly and at an ever decreasing rate, into matter and time comprising the universe."

I believe saying all of space time existed as a single point is only a simplification and it's wrong to take that as an absolute. In the same way people say that elementary particles (or even atoms/molecules) are "points". In reality what we mean is just that for our purposes they are so small they might as well be considered infinitely small "mathematical" points since it makes calculations and theory easier. (EDIT: In this case, when talking about the big bang and the universe, it's actually wrong to talk about a point because the universe might still have been infinitely big, but it was infinitely compressed.)

On Wikipedia they wrote the following about big bang, "The model describes how the universe expanded from a very high-density and high-temperature state" which is a better description imo.

I think it's also wrong to say time began with the big bang, it's just we don't know what happened before t=10-12 s from big bang so we can only speculate about what the universe was like before that.

Indeed it's hard to imagine nothingness, but it is also wrong to assume there was nothingness before the big bang. We just don't know -- that is the hard thing we have to accept!
« Last Edit: February 04, 2019, 11:27:57 pm by apis »
 

Offline timelessbeing

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Re: Help to understand the Big Bang
« Reply #16 on: February 04, 2019, 11:20:09 pm »
I don't think there was necessarily nothingness. There could have been "something", but just arranged in a different way.

Maybe a big crunch or collision of some sort. Maybe a energy manifested in a different shape....
 

Offline MT

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Re: Help to understand the Big Bang
« Reply #17 on: February 04, 2019, 11:21:05 pm »
Right now the theory among multiverse dudes/duddetts is that there are many universes each coming from many big bangs who in turn is the other end of the black hole who in it self is sort of holograms that preserves all information of the  galaxies and finally the universe it swallows up along the way, data is contained on the rim of the hole. The whole thing is according to them a oscillation moment, destruction and construction (no god involved).

For me? I have no clue im just an onlooker and accepts any kind of hypothesis. :)
« Last Edit: February 04, 2019, 11:23:00 pm by MT »
 

Offline bsudbrink

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Re: Help to understand the Big Bang
« Reply #18 on: February 04, 2019, 11:21:55 pm »
What if entire civilizations existed and perished during those "first few seconds"?
The universe was just a very homogeneous soup. Not enough complexity for anything to exist. Not even molecules.
Yes, the supposed conditions in the early universe would prevent atoms and molecules as they exist now.  But what if behaviors of matter that (due to our prevailing conditions) we can no longer understand or describe (that we now describe as random and incredibly brief when we glimpse them in a particle accelerator) allowed kinds of order on a very small scale, for very brief periods of time?  But the basic questions are "Small compared to what?" and "Brief compared to what?".  What do you compare against when the prevailing conditions are such that you would imagine "back then"?
 

Offline timelessbeing

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Re: Help to understand the Big Bang
« Reply #19 on: February 04, 2019, 11:43:20 pm »
What can I say... very imaginative.
 

Offline bsudbrink

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Re: Help to understand the Big Bang
« Reply #20 on: February 05, 2019, 12:20:25 am »
Imaginative, I guess.  And certainly meaningless, as the conditions "back then" can have no more impact on "now" as can events beyond our light cone.

But I still find it interesting to speculate...

I would invite you to go the other direction.  Say, ten to the power one-hundred years from now.  As I understand it, all of the mass in the universe will be in the form of iron atoms.  It will no longer be possible to concentrate enough energy to split or fuse them.  They will be the indivisible particles, the point masses.  They will be evenly distributed, moving at random.  Energy will be minimized at all points.  But think of entropy (that universal laws seem to maximize).  Suddenly (or maybe very gradually, depending on how you look at it) entropy will be gone.  The universe will be highly homogeneous.  Will the greater laws of physics and mathematics allow this condition to persist?  Maybe there will be some kind of "additional big bang (or "really big ripple")".  Some kind of spontaneous symmetry breaking.  Pressure waves moving through the gas, caused by some quantum behavior.  Those pressure waves might take on very interesting and complex patterns.  It might require millions of years of "watching" thousands of cubic light-years of space to see them, but so what?  The universe has the time.
 

Online edy

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Re: Help to understand the Big Bang
« Reply #21 on: February 05, 2019, 12:48:15 am »
Isn't there some theory that we "pinched off" from another Universe... parallel to our own but not possible to observe as we are in different dimensions? In that case, things got all started by a "previous" entity. I have trouble understanding time itself, how it can be treated like one of the 3 spacial dimensions (spacetime), and I also have a very naive view of space built up from personal experience. I keep imagining we are just a large MMORPG simulation.  :-DD
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Offline apis

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Re: Help to understand the Big Bang
« Reply #22 on: February 05, 2019, 12:59:22 am »
But I still find it interesting to speculate...
Have you heard of a Boltzmann brain? If not you might find this interesting:
 
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Offline timelessbeing

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Re: Help to understand the Big Bang
« Reply #23 on: February 05, 2019, 02:27:01 am »
As I understand it, all of the mass in the universe will be in the form of iron atoms.  It will no longer be possible to concentrate enough energy to split or fuse them.  They will be the indivisible particles, the point masses.
After black holes evaporate, won't there just be white and brown dwarfs and neutron stars accelerating apart? "big rip" theory says that eventually even matter will decay into fundamental subatomic particles. I think any quantum waves will be spread infinitely far apart and very weak and uninteresting.


I have trouble understanding time itself, how it can be treated like one of the 3 spacial dimensions (spacetime)
I don't think astrophysicists treat time as a spacial dimension. Rather space and time are interconnected parts of a overarching concept. You can't affect one without affect the other because they are relative, hence relativity. Minute Physics has nice videos about it.

 

Offline xrunner

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Re: Help to understand the Big Bang
« Reply #24 on: February 05, 2019, 02:41:05 am »
The Big Bang was just a result of existing branes crashing into each other -

https://arxiv.org/abs/hep-th/0103239

Now where did the branes come from?  :box:
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