Is Big Bang True? Physics and SR/GR

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In summary, scientists have found evidence that contradicts the big bang theory. The first problem involves the three predictions that the theory makes, that the universe is expanding, that the cosmic background radiation exists and that the abundances of light elements are correct. The second problem is that the universe is presumed to have started out smooth and homogeneous, like the background radiation. Recent observations have shown the actual universe to be profoundly discontinuous and clumpy. A part of the problem is that the alleged "dark matter" does not seem to exist at all. The third problem is that if the big bang occurred 20 billion years ago, it seems logical to assume that nothing in the universe can be older than this. Yet, mammoth clusters of galaxies have been discovered
  • #71
Chiclayo guy said:
If the Big Bang was thought of as an event of no real consequence – not really the beginning of anything - merely a hiccup or burp in an eternal and infinite universe, would that in any way influence the thinking, assumptions or focus of present investigation?

We would only think this if we found evidence for it, which would most definitely influence many things.
 
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  • #72
Chiclayo guy said:
If the Big Bang was thought of as an event of no real consequence – not really the beginning of anything - merely a hiccup or burp in an eternal and infinite universe, would that in any way influence the thinking, assumptions or focus of present investigation?

It wouldn't affect the big bang model, no. The big bang model merely attempts to describe the universe after the big bang, how the particles and elements formed, and how structures developed.

As Drakkith points out, it most certainly would have an affect on our thinking in other areas. But if we discovered the big bang was the beginning, I think that would have an effect too - we don't know which is true, even though the idea of the big bang being the beginning of time became more popular because of the Hawking-Penrose singularity theorems. What happened at or before the big bang doesn't have any relevance to the big bang model itself.
 
  • #73
Q: So, is Big Bang true or wrong?

A: Its definitely not true ... since any scientific theory can't be proven (can be only confirmed to a certain level).
This is a wrong question to me and it should not bother science.
 
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  • #74
Flowerpunkt said:
Q: So, is Big Bang true or wrong?

A: Its definitely not true ... since any scientific theory can't be proven (can be only confirmed to a certain level).
This is a wrong question to me and it should not bother science.

We have a preponderance of evidence that the universe started off very small and very dense. You are correct that it cannot be "proven". Science does not attempt to prove things. However, science is perfectly happy with moving forward based on our best models, and we have a pretty good one regarding the Big Bang.
 
  • #75
Flowerpunkt said:
Q: So, is Big Bang true or wrong?

A: Its definitely not true ... since any scientific theory can't be proven (can be only confirmed to a certain level).
This is a wrong question to me and it should not bother science.
It is true in the sense that it's an accurate description of reality...up to a point.
 
  • #76
there are various proposals,
Hartle-Hawking's no-boundary wave function, Linde's wave function, Vilenkin's tunneling wave
function...
they predict different types of gravity waves.
 
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  • #77
DaveC426913 said:
We have a preponderance of evidence that the universe started off very small and very dense. You are correct that it cannot be "proven". Science does not attempt to prove things. However, science is perfectly happy with moving forward based on our best models, and we have a pretty good one regarding the Big Bang.

As an unofficial representative of the average public mind let me suggest that this is one of the issues within cosmology that absolutely confounds Mr John Q Public. If I may paraphrase hundreds if not thousands of comments…”The universe started everywhere, not at one central point.” Everywhere to me implies vastness…lots of distance plus locations like ‘here’ and ‘there.’

To say that the universe “started off very small” (I have seen estimates of golf ball and grapefruit size) seems to me to be diametrically opposed to ‘everywhere.’ I’ve tried to reconcile the problem by merging the two views… the universe started everywhere within the golf ball, but that sounds more like tap dancing than a plausible explanation.

I’m sure I’m not understanding something, but I’m just as certain that my fellow average public minds are as confused as I am. Is there no way to put layman speak to the issue so we can put it aside and go on to other concepts that we have absolutely no understanding of?
 
  • #78
Chiclayo guy said:
I’m sure I’m not understanding something, but I’m just as certain that my fellow average public minds are as confused as I am. Is there no way to put layman speak to the issue so we can put it aside and go on to other concepts that we have absolutely no understanding of?
The way I usually prefer to put it is that in the distant past, things in our universe were much closer together. Go early enough, and everything that we can see was once contained in a volume smaller than an atom. Now, we're pretty sure that the universe continues some distance beyond what we can see, so we don't know just how big the universe was (if it even has a size!), but everything we can see came from just one teeny tiny patch.
 
  • #79
Chiclayo guy said:
I have seen estimates of golf ball and grapefruit size
I think you'll find that those are estimates of the OBSERVABLE UNIVERSE at the beginning, NOT "the universe"
 
  • #80
Chiclayo guy said:
I’m sure I’m not understanding something, but I’m just as certain that my fellow average public minds are as confused as I am. Is there no way to put layman speak to the issue so we can put it aside and go on to other concepts that we have absolutely no understanding of?

Imagine if everything in the observable universe (that means the parts we can see) occupied a volume of space no bigger than a golf ball. Now imagine a possibly infinite number of golf balls surrounding ours in every direction. That is what we think the early universe was like. Hot, dense, and still possibly infinite in size.
 
  • #81
One point to add to the previous few posts - even if the universe is finite (e.g. it has a positively curved topology, or that of a 3-torus), it remains true that it has no boundary. To get an analogy in lower dimensions, think of the surface of the earth. It has no edge, no boundary, but we can still speak of it's overall size (the distance required to circumnavigate it's surface). Generalize this to three dimensions. No matter how far you travel, you'll never encounter an edge. You'll just wrap back around, like a three dimensional analogue of Pac-man.

So, we can say two things - the universe has no boundary, and it has no outside.
 
  • #82
I have heard OP's arguments before. It was in a creationist VS science debate, to discredit the big bang theory and science, without bringing forward any proof to show why their model of the universe would be more plausible.
 
  • #83
cueball B said:
I have heard OP's arguments before. It was in a creationist VS science debate, to discredit the big bang theory and science, without bringing forward any proof to show why their model of the universe would be more plausible.

Yes, the OP was presenting a thoroughly non-scientific point of view and you will notice that once people pushed back on his nonsense he was not heard from again.
 
  • #84
cueball B said:
I have heard OP's arguments before. It was in a creationist VS science debate, to discredit the big bang theory and science, without bringing forward any proof to show why their model of the universe would be more plausible.

Boys listen to this and have a laugh. I have wondered for weeks what this "OP argument" was. I am interested in cosmology and alternative cosmologies, and I believed it had to be some well-known philosophical argument, and searched it on the internet. I found hundreds of citations of the socalled "OP argument", in many different fields, and I was puzzled about what it was, or what O and P stand for or who was this OP... I was about to write here to ask, when I eventually came across a site about internet slang, where I finally understood that OP stands for "Original Poster", and so it is not a specific argument! :-D
 
  • #85
Well, if you push the universe back to t=0, it was not even the size of a golf ball, or even an atom - it was a point of zero size and infinite density. Most cosmologists would agree this is unrealistic and signals the laws of physics, as we know them, are incomplete. It's not much different than the case of a point charge which, in theory, should have an infinite charge density. We are still working on the cosmological case by trying to formulate a theory of quantum gravity.
 
<h2>1. What is the Big Bang theory?</h2><p>The Big Bang theory is a scientific explanation for the origin and evolution of the universe. It states that the universe began as a singularity, a point of infinite density and temperature, approximately 13.8 billion years ago. This singularity then expanded rapidly, creating the universe we know today.</p><h2>2. How do we know the Big Bang actually happened?</h2><p>Scientists have gathered evidence from various fields of study, such as cosmology, astronomy, and particle physics, to support the Big Bang theory. This evidence includes the expansion of the universe, the cosmic microwave background radiation, and the abundance of light elements. Additionally, the predictions made by the theory have been consistently confirmed by observations and experiments.</p><h2>3. What is the role of physics in understanding the Big Bang?</h2><p>Physics plays a crucial role in understanding the Big Bang. The theory is based on fundamental principles of physics, such as Einstein's theory of general relativity and the laws of thermodynamics. Physics also helps us understand the behavior of matter and energy in the early universe and how it led to the formation of galaxies, stars, and planets.</p><h2>4. What is special relativity (SR) and general relativity (GR)?</h2><p>Special relativity (SR) is a theory developed by Albert Einstein that describes the relationship between space and time in the absence of gravity. It explains how the laws of physics are the same for all observers moving at a constant velocity. General relativity (GR) is a theory that extends SR to include the effects of gravity. It explains how massive objects, such as planets and stars, affect the curvature of space and time.</p><h2>5. How does the Big Bang theory relate to special and general relativity?</h2><p>The Big Bang theory is consistent with both special and general relativity. SR is used to describe the expansion of the universe and the behavior of matter and energy in the early stages of the universe. GR is used to explain the large-scale structure of the universe and how gravity affects the evolution of the universe. The Big Bang theory also helps us understand the origin of the cosmic microwave background radiation, which is a key prediction of GR.</p>

1. What is the Big Bang theory?

The Big Bang theory is a scientific explanation for the origin and evolution of the universe. It states that the universe began as a singularity, a point of infinite density and temperature, approximately 13.8 billion years ago. This singularity then expanded rapidly, creating the universe we know today.

2. How do we know the Big Bang actually happened?

Scientists have gathered evidence from various fields of study, such as cosmology, astronomy, and particle physics, to support the Big Bang theory. This evidence includes the expansion of the universe, the cosmic microwave background radiation, and the abundance of light elements. Additionally, the predictions made by the theory have been consistently confirmed by observations and experiments.

3. What is the role of physics in understanding the Big Bang?

Physics plays a crucial role in understanding the Big Bang. The theory is based on fundamental principles of physics, such as Einstein's theory of general relativity and the laws of thermodynamics. Physics also helps us understand the behavior of matter and energy in the early universe and how it led to the formation of galaxies, stars, and planets.

4. What is special relativity (SR) and general relativity (GR)?

Special relativity (SR) is a theory developed by Albert Einstein that describes the relationship between space and time in the absence of gravity. It explains how the laws of physics are the same for all observers moving at a constant velocity. General relativity (GR) is a theory that extends SR to include the effects of gravity. It explains how massive objects, such as planets and stars, affect the curvature of space and time.

5. How does the Big Bang theory relate to special and general relativity?

The Big Bang theory is consistent with both special and general relativity. SR is used to describe the expansion of the universe and the behavior of matter and energy in the early stages of the universe. GR is used to explain the large-scale structure of the universe and how gravity affects the evolution of the universe. The Big Bang theory also helps us understand the origin of the cosmic microwave background radiation, which is a key prediction of GR.

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