Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: lassewe on 17/06/2018 21:03:59
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Since heat and temprature is just atoms and molecules moving fast relative to each other. And since the warmer somthing is the faster they move then there has got to be an upper limit to temprature, just like there is a lower limit, 0 kelvin. Since nothing can move faster than light that has to be the upper limit, if not something else already limits it.
That's where I have a problem with the big bang theory because the theory revolves around the universe expanding from a single point aka a singularity. So the universe acording to the theory has been infintively small at one point. Since energy cannot be created, there has to be the same amount of energy in the universe from the point of the big bang to now. That means that since the only sort of energy that existed back then was heat there had to be an infinite temprature because all the heat was centered at one single point. But how can this be if there is an upper limit to temprature?
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Hi Lassewe, welcome.
That's where I have a problem with the big bang theory because the theory revolves around the universe expanding from a single point aka a singularity.
Don’t be derailed by the concept of a singularity. Chris Baird says of singularities:
“In general, singularities are the non-physical mathematical result of a flawed physical theory. When scientists talk about black hole singularities, they are talking about the errors that appear in our current theories and not about objects that actually exist.”
I think it is worth keeping in mind that the same would apply to a BB singularity.
So the universe acording to the theory has been infintively small at one point.
Chris Baird, again:
“….infinities never exist in the real world. Whenever an infinity pops out of a theory, it is simply a sign that your theory is too simple to handle extreme cases. [/quote]
This must suggest that “an infinite temperature” is not something that would occur in the real world.
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Since heat and temprature is just atoms and molecules moving fast relative to each other. And since the warmer somthing is the faster they move then there has got to be an upper limit to temprature, just like there is a lower limit, 0 kelvin. Since nothing can move faster than light that has to be the upper limit, if not something else already limits it.
That's where I have a problem with the big bang theory because the theory revolves around the universe expanding from a single point aka a singularity. So the universe acording to the theory has been infintively small at one point. Since energy cannot be created, there has to be the same amount of energy in the universe from the point of the big bang to now. That means that since the only sort of energy that existed back then was heat there had to be an infinite temprature because all the heat was centered at one single point. But how can this be if there is an upper limit to temprature?
1. The singularity is generally conceded to be an artifact of the inadequacy of current theory to explain everything.
2. Atoms did not exist in the very earliest stages of the universe. It required the temperature to become low enough and for the separation of forces to occur before these could form.
3. Conclusion: your perceived objections are invalid.
Caveat: I am a geologist, not a cosmologist, so the foregoing is a gross simplification, but I believe it is fundamentally accurate.
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Since nothing can move faster than light that has to be the upper limit, if not something else already limits it.
Welcome to the forum! :)
Your assumption is incorrect. The relativistic kinetic energy, K ,of a particle is given by the expression
K = [( - 1/√(1 - v2/c2)]m0c2
where m0 is the particle's rest mass, v is the speed of the particle and c is the speed of light. If you take a close look at that expression you'll notice that as v approaches the speed of light the kinetic energy goes to infinity. So for any kinetic energy that you can imagine there is a finite speed associated with it.
That's where I have a problem with the big bang theory because the theory revolves around the universe expanding from a single point aka a singularity. So the universe acording to the theory has been infintively small at one point. Since energy cannot be created, there has to be the same amount of energy in the universe from the point of the big bang to now.
That is incorrect. There is the same amount of energy before the big bang as there is now. The total amount of energy in the universe is zero. That's how energy remain conserved as it was created. There's two kinds of energy; positive and negative. Negative energy comes from gravitational potential energy and positive energy comes from particles. You can read about it in The Inflationary Universe by Alan Guth. I can make those pages available to you if you'd like?
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1. The singularity is generally conceded to be an artifact of the inadequacy of current theory to explain everything.
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3. Conclusion: your perceived objections are invalid.
Neither of those two assertions of yours are correct. The OP never used the term "objection" just problem or can't. Where the OP said can't he/she was merely wrong, that's all.
It's bad juju to tell a newbie that what they're speculating/asking about is invalid.
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The total amount of energy in the universe is zero.
I have no problem with the assertion that the balance of energy in the Universe is zero.
However, I find myself wondering if that is actually the same as saying the “total amount” is zero.
If there is x amount of +ve energy, that is an amount.
If there is x amount of -ve energy, that is an amount.
One may cancel the other, so that the balance is zero, but there is still x amount of +ve and x amount of -ve energy; or can they mutually destroy each other?
If so, can energy be destroyed?
I’m willing to believe my reasoning is off track, but I need to know where.
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1. The singularity is generally conceded to be an artifact of the inadequacy of current theory to explain everything.
...
3. Conclusion: your perceived objections are invalid.
Neither of those two assertions of yours are correct. The OP never used the term "objection" just problem or can't. Where the OP said can't he/she was merely wrong, that's all.
It's bad juju to tell a newbie that what they're speculating/asking about is invalid.
Can you explain what you think is the difference between my statement and that of Chris Baird, quoted by Bill S. (Bill, I would welcome your input here also.) For your convenience here are both statements.
My statement: "The singularity is generally conceded to be an artifact of the inadequacy of current theory to explain everything."
"“In general, singularities are the non-physical mathematical result of a flawed physical theory. When scientists talk about black hole singularities, they are talking about the errors that appear in our current theories and not about objects that actually exist.”
In my caveat I made clear my statement was a simplification, but it seems to me wholly consistent with the Baird quote.
The OP never used the term "objection" just problem or can't. Where the OP said can't he/she was merely wrong, that's all.
The OP was raising objections to Big Bang Theory that accounted for them having a problem with it. They did not need to use the word objection in order to be making one. Up until this point I have not used the word disagreement, yet, based on the previous sentences, you would be correct to say I was in disagreement with you. I was correct to note that the OP had objections. And that was perfectly fine: objections are the lifeblood of the scientific method.
It's bad juju to tell a newbie that what they're speculating/asking about is invalid.
I quite agree, but since I didn't do that there is no issue. I told them that their conclusion was invalid, not that what they were speculating about was invalid. You know, the way you told them directly that they were incorrect and repeated here that they were "merely wrong". Check out a dictionary sometime - you may find that invalid, incorrect and wrong are considered to be synonyms.
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I have no problem with the assertion that the balance of energy in the Universe is zero.
See: http://www.newenglandphysics.org/ask_a_physicist/guth_grav_energy.pdf
However, I find myself wondering if that is actually the same as saying the “total amount” is zero.
Seems to be a matter of semantics to me.
If there is x amount of +ve energy, that is an amount.
If there is x amount of -ve energy, that is an amount.
What does "+ve energy" etc mean? I never saw that term before.
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Don’t be derailed by the concept of a singularity. Chris Baird says of singularities:
“In general, singularities are the non-physical mathematical result of a flawed physical theory. When scientists talk about black hole singularities, they are talking about the errors that appear in our current theories and not about objects that actually exist.”
I think it is worth keeping in mind that the same would apply to a BB singularity.
So the universe acording to the theory has been infintively small at one point.
MAY have been.
Chris Baird, again:
“….infinities never exist in the real world. Whenever an infinity pops out of a theory, it is simply a sign that your theory is too simple to handle extreme cases.
What's the charge density of an electron? :)
I don't buy any of what Baird claims. There's nothing in physics that implies something can't be infinite, such as singularities. And its a matter of fact that if the universe is an open one, which it appears to be more and more, then there's an infinite amount of matter in the universe.
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And its a matter of fact that if the universe is an open one, which it appears to be more and more, then there's an infinite amount of matter in the universe.
That is, as long as you don't interpret a "fact" as something that requires physical/experimental confirmation.
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What does "+ve energy" etc mean? I never saw that term before.
Sorry if my non-expert terminology is confusing. Perhaps the following reference to positive and negative energy might help to rectify the situation.
https://www.google.co.uk/search?q=what+is+a+positive+and+negative+energy+balance&oq=is+there+positive+and+negative+energy+&aqs=chrome.2.69i57j0l5.24634j1j1&sourceid=chrome&ie=UTF-8
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What's the charge density of an electron?
Pete, you know I don’t have the maths to do justice to this, but if asked a question, I like to do my best to respond.
Besides, some day I may want to take you to task for not answering. :)
My understanding is that the charge density of a particle is the ratio of its charge to its volume.
Charge/volume. (?)
I assume, from the context; also from a post of yours in Physics Forums that I struggled with a few years ago; that you are saying that the charge density of an electron is infinite (?)
My thoughts would be along the lines that the charge is finite and the volume is finite, so although the ratio may be mathematically “infinite”, two finite entities do not equal a physical infinity.
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Just to make things _even more complicated and confusing_ --- What is generally understood to be described by the 'Big Bang' in current models, describes a period _post inflation_ .
As pmbphy suggested, Alan Guth is the go to guy on inflation. Highly worth a look..... I read _The Inflationary Universe_ and managed to digest about half of it.
Also, no model of the BB suggests that things emerged from a point or a singularity..... that is just a mathematical consequence of trying to work events backwards following an incomplete model. Quantum mechanics (sort of) avoids this problem, but has a bunch of others. BB simply starts out with the universe in a very hot and dense state.... however, not unlike when the football game on TV runs long, it 'joins the universe already in progress.'
It is worth noting, that in such a postulated hot dense state in which the universe is speculated to have existed way back 13.7 Billion years ago, there are some really funky consequences, like the four forces being indistinguishable (or really basicly one) and when you have such high energy levels in such close quarters, there is the (speculative) possibility for the creation and rapid decay of largely unimaginable and exotic highly massive particles that can (likely) never be replicated...... really some far out stuff. A lot of the conventional stuff we think about in our current macroscopic universe really doesn't apply -- or at least applies really differently when things are expressed at extreme scales too (e.g. very high energy, very large, very small, etc) -- opens up whole different ballgames.
diogenesNY
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" That means that since the only sort of energy that existed back then was heat there had to be an infinite temprature because all the heat was centered at one single point. "
Not as I get it. The Big Bang does not postulate an 'infinite temperature' to start with, and the 'single point' you discuss doesn't exist, at least not in our 'dimensions'. And as inflation (sorry, 'accelerating expansion') still happens new 'points' gets set in, and as far as I see they too becomes 'inseparable origins' of that Big Bang.
" There should be an upper limit, smaller than the Planck scale, to the temperature of the Universe in the distant past. This is also a signature that shows up in the cosmic microwave background: how high a temperature the Universe reached at its hottest. Remember, if there were no inflation, the Universe should have gone up to arbitrarily high temperatures at early times, approaching a singularity. But with inflation, there's a maximum temperature that must be at energies lower than the Planck scale (~1019 GeV). What we see, from our observations, is that the Universe achieved temperatures no higher than about 0.1% of that (~1016 GeV) at any point, further confirming inflation."
https://www.forbes.com/sites/startswithabang/2017/05/11/what-if-cosmic-inflation-is-wrong/#6afa0fce8e50