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Member (Idle past 3855 days) Posts: 390 From: Irvine, CA, United States Joined: |
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Author | Topic: Does the universe have total net energy of zero? | |||||||||||||||||||||||
subbie Member (Idle past 1276 days) Posts: 3509 Joined: |
Wow. You can't even read your own sources. That's Buz level wrong.
Abusive ad hominem (also called personal abuse or personal attacks) usually involves insulting or belittling one's opponent in order to attack his claim or invalidate his argument... My emphasis. Calling you a twit for the sole purpose of alerting others to your twithood with no intent to attack your claim or invalidate your argument is not ad hominem, as the source you quote makes clear. But thanks for trying. If at first you don't succeed, at least do something to amuse your audience.Ridicule is the only weapon which can be used against unintelligible propositions. -- Thomas Jefferson We see monsters where science shows us windmills. -- Phat It has always struck me as odd that fundies devote so much time and effort into trying to find a naturalistic explanation for their mythical flood, while looking for magical explanations for things that actually happened. -- Dr. Adequate ...creationists have a great way to detect fraud and it doesn't take 8 or 40 years or even a scientific degree to spot the fraud--'if it disagrees with the bible then it is wrong'.... -- archaeologist
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Admin Director Posts: 13018 From: EvC Forum Joined: Member Rating: 1.9 |
To all participants:
Please keep the focus on the topic. If you feel someone is wrong then it is incumbent upon you to explain how they are wrong.
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kbertsche Member (Idle past 2153 days) Posts: 1427 From: San Jose, CA, USA Joined: |
quote:This is called a "thought experiment" and has a grand tradition in physics. Thought experiments are very helpful in figuring out how to think about a problem. The basic idea is that gravity "wants" to pull things together. If no other forces counteract it, gravity will do so. In principle, this gravitational force could be harnessed to do work on an external device such as a generator. (Force times distance equals work or energy). This extracts energy from the gravitational field. Thus the gravitational field loses energy. Imagine two masses that are infinitely far apart. There is no gravitational force between them, and no gravitational energy in the system. As they move closer together, they can do work on (supply energy to) an external device like a generator. But since energy is conserved, and positive energy has been extracted to the generator, the gravitational field must contain negative energy. Edited by kbertsche, : Add last paragraph"Science without religion is lame, religion without science is blind." — Albert Einstein I am very astonished that the scientific picture of the real world around me is very deficient. It gives us a lot of factual information, puts all of our experience in a magnificently consistent order, but it is ghastly silent about all and sundry that is really near to our heart, that really matters to us. It cannot tell us a word about red and blue, bitter and sweet, physical pain and physical delight; it knows nothing of beautiful and ugly, good or bad, God and eternity. Science sometimes pretends to answer questions in these domains, but the answers are very often so silly that we are not inclined to take them seriously. — Erwin Schroedinger
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designtheorist Member (Idle past 3855 days) Posts: 390 From: Irvine, CA, United States Joined: |
The basic idea is that gravity "wants" to pull things together. If no other forces counteract it, gravity will do so. In principle, this gravitational force could be harnessed to do work on an external device such as a generator. (Force times distance equals work or energy.). This extracts energy from the gravitational field. I still don't get it. Can you answer the individual questions I asked? I don't understand how gravitational field energy could be used to run a generator as in Guth's analogy. Okay, you have added a new paragraph. I still don't get it. You write:
But since energy is conserved, and positive energy has been extracted to the generator, the gravitational field must contain negative energy. Are you saying that as you extract energy from the gravitational field then the negative gravitational field energy becomes stronger? That seemed to be Guth's claim as well. It is an interesting thought but I still don't see how energy would be extracted without an energy expenditure. Edited by designtheorist, : No reason given.
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designtheorist Member (Idle past 3855 days) Posts: 390 From: Irvine, CA, United States Joined: |
From Wikipedia article on Potential Energy:
Why choose a convention where gravitational energy is negative? Gravitational potential is a scalar potential energy per unit mass at each point in space associated with the force fields. Notice at r tends to infinity, ϕ tends to 0 :.As with all potential energies, only differences in gravitational potential energy matter for most physical purposes, and the choice of zero point is arbitrary. Given that there is no reasonable criterion for preferring one particular finite r over another, there seem to be only two reasonable choices for the distance at which U becomes zero: r = 0 and . The choice of U = 0 at infinity may seem peculiar, and the consequence that gravitational energy is always negative may seem counterintuitive, but this choice allows gravitational potential energy values to be finite, albeit negative. The singularity at r = 0 in the formula for gravitational potential energy means that the only other apparently reasonable alternative choice of convention, with U = 0 for r = 0, would result in potential energy being positive, but infinitely large for all nonzero values of r, and would make calculations involving sums or differences of potential energies beyond what is possible with the real number system. Since physicists abhor infinities in their calculations, and r is always non-zero in practice, the choice of U = 0 at infinity is by far the more preferable choice, even if the idea of negative energy appears to be peculiar at first. The negative value for gravitational energy also has deeper implications that make it seem more reasonable in cosmological calculations where the total energy of the universe can meaningfully be considered; see inflation theory for more on this. So is the claim then that all of the positive energy of matter and energy is offset by the potential negative energy of the gravitational field? Are Krauss and the others who hold to zero energy universe offsetting real energy in the universe with potential gravitational energy?
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designtheorist Member (Idle past 3855 days) Posts: 390 From: Irvine, CA, United States Joined: |
Please compare these two comments from you:
Not only do you know nothing about the topic, you don't even know what an ad hominem is. and
Calling you a twit for the sole purpose of alerting others to your twithood with no intent to attack your claim or invalidate your argument is not ad hominem... As you can plainly see, you were trying to "attack" my claim by saying I don't know anything about the topic even as you called me a twit. Personal abuse and name-calling is always an ad hom attack. Just so you know.
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subbie Member (Idle past 1276 days) Posts: 3509 Joined: |
Personal abuse and name-calling is always an ad hom attack. Just so you know. I have explained to you that this is not the case. The only authority you quoted explained that this is not the case. I can only conclude that you are ineducable. Whether this is due to handicap, sloth or stubbornness I will not venture to guess. However, it does establish to my satisfaction the futility of continued communication with you, in case observing your interactions with others here over the last 3 months was not sufficient.Ridicule is the only weapon which can be used against unintelligible propositions. -- Thomas Jefferson We see monsters where science shows us windmills. -- Phat It has always struck me as odd that fundies devote so much time and effort into trying to find a naturalistic explanation for their mythical flood, while looking for magical explanations for things that actually happened. -- Dr. Adequate ...creationists have a great way to detect fraud and it doesn't take 8 or 40 years or even a scientific degree to spot the fraud--'if it disagrees with the bible then it is wrong'.... -- archaeologist
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designtheorist Member (Idle past 3855 days) Posts: 390 From: Irvine, CA, United States Joined: |
I was originally grateful for the offer, but I should not have that attitude.
Any on topic post from you would be welcome. Edited by designtheorist, : No reason given.
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Admin Director Posts: 13018 From: EvC Forum Joined: Member Rating: 1.9 |
Please do not post messages with no on-topic content.
Please keep your focus on the position and not on the perceived foibles of the person holding the position. Please explain and clarify your position as many times as necessary without becoming frustrated. Please explain how someone is wrong if you think they are wrong. Please don't complain if you ignore the above and get suspended after this thread is reopened.
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Admin Director Posts: 13018 From: EvC Forum Joined: Member Rating: 1.9 |
Please follow the moderator requests in the previous message. Thanks.
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kbertsche Member (Idle past 2153 days) Posts: 1427 From: San Jose, CA, USA Joined: |
I'll try again to answer your questions, but I'm not sure that I can explain it any better than I've already tried to do.
quote:Yes, really. If energy is conserved, and positive energy was extracted from the gravitational field, then the gravitational field energy must have become more negative. quote:If the mass is held constant, then as it shrinks to a smaller and smaller volume, the gravitational field becomes stronger and the gravitational field energy becomes more negative. As your wiki article said, if the mass were to shrink to a size of zero the gravitational field energy would become infinite. quote:No, the volume is reduced, but the mass remains fixed. The mass does not reduce. quote:Then you haven't quite grasped the arguments yet. Guth's and wikipedia's arguments should be persuasive. quote:Good points. I agree that it seems incredible that gravitational energy can offset the mass energy of the universe. I don't have a simple explanation or illustration for this. But I have no solid reason to doubt or deny it, either. It may well be true. Physics offers many examples of things which challenge our intuition until we learn how to think about them correctly. "Science without religion is lame, religion without science is blind." — Albert Einstein I am very astonished that the scientific picture of the real world around me is very deficient. It gives us a lot of factual information, puts all of our experience in a magnificently consistent order, but it is ghastly silent about all and sundry that is really near to our heart, that really matters to us. It cannot tell us a word about red and blue, bitter and sweet, physical pain and physical delight; it knows nothing of beautiful and ugly, good or bad, God and eternity. Science sometimes pretends to answer questions in these domains, but the answers are very often so silly that we are not inclined to take them seriously. — Erwin Schroedinger
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designtheorist Member (Idle past 3855 days) Posts: 390 From: Irvine, CA, United States Joined: |
I like thought experiments. The one you proposed is not clear to me but a very similar thought experiment is clear.
Imagine an asteroid on a near collision course with an earth-like planet. As the asteroid approaches the planet, the gravitational field energy is increased and the kinetic energy (velocity) is increased. Based on the conservation of energy, the gravitational field energy must be negative.
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kbertsche Member (Idle past 2153 days) Posts: 1427 From: San Jose, CA, USA Joined: |
quote:Yes, that's the claim. They are offsetting the positive mass energy of the universe with the negative, potential gravitational energy. (Note: both are equally "real" and physical). Dark matter and dark energy must also be added into the equation. "Science without religion is lame, religion without science is blind." — Albert Einstein I am very astonished that the scientific picture of the real world around me is very deficient. It gives us a lot of factual information, puts all of our experience in a magnificently consistent order, but it is ghastly silent about all and sundry that is really near to our heart, that really matters to us. It cannot tell us a word about red and blue, bitter and sweet, physical pain and physical delight; it knows nothing of beautiful and ugly, good or bad, God and eternity. Science sometimes pretends to answer questions in these domains, but the answers are very often so silly that we are not inclined to take them seriously. — Erwin Schroedinger
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kbertsche Member (Idle past 2153 days) Posts: 1427 From: San Jose, CA, USA Joined: |
quote:This is a reasonable example. As in Guth's example, if the ropes and generators were absent and the mass shell were allowed to freely contract, then the elements of the mass shell would be accelerated toward the center and would gain kinetic energy. This kinetic energy comes from the gravitational field, the energy of which becomes more negative. "Science without religion is lame, religion without science is blind." — Albert Einstein I am very astonished that the scientific picture of the real world around me is very deficient. It gives us a lot of factual information, puts all of our experience in a magnificently consistent order, but it is ghastly silent about all and sundry that is really near to our heart, that really matters to us. It cannot tell us a word about red and blue, bitter and sweet, physical pain and physical delight; it knows nothing of beautiful and ugly, good or bad, God and eternity. Science sometimes pretends to answer questions in these domains, but the answers are very often so silly that we are not inclined to take them seriously. — Erwin Schroedinger
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NoNukes Inactive Member |
How are you defining controversy? Is it controversial if an informed person holds a contrary opinion? I think that is a reasonable definition in the circumstances. I thought it was intriguing that he came to the view that light did not warp space when discussing the same topic that brought me to the issue - dark energy. A single contrary article on the internet does not establish a controversy regarding regarding General Relativity. But let's consider Gowan's theory. He believes that there is no dark energy, and that the effect attributed to dark energy is provided by not allowing photons to produce a gravitational effect. As best as I can tell, that idea does NOT extend to kinetic energy or thermal energy those quantities do not have the relativistic properties that Gowan claims makes light unique.
quote: So the only thing this guy's ideas have in common with yours is that he doesn't want to include radiation as contributing to a gravitational field. But if he is correct, then there is no dark energy that makes up 75 percent of the cosmos. Dark matter and ordinary energy plus a funky behavior of light explain everything. So why even cite Gowan's work? It doesn't help you in any way and you don't even subscribe to his theory.
I am unwilling to simply believe in GR theory when so much new evidence is calling it into question What evidence is that? Certainly it is not the accelerated expansion of the universe. With inclusion of a properly valued cosmological constant, GR models an accelerating universe. Edited by NoNukes, : No reason given.
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