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Member (Idle past 4025 days) Posts: 390 From: Irvine, CA, United States Joined: |
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Author | Topic: Does the universe have total net energy of zero? | |||||||||||||||||||||||||||||||||||||||||||
designtheorist Member (Idle past 4025 days) Posts: 390 From: Irvine, CA, United States Joined:
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The thread proposal was rewritten in Message 11, please start there. --Admin
As I was reading The Grand Design by Stephen Hawking, I came across this passage: "If the total energy of the universe must always remain zero, and it costs energy to create a body, how can a whole universe be created from nothing? That is why there is a law like gravity. Because gravity is attractive, gravitational energy is negative: One has to do work to separate a gravitationally bound system, such as the earth and moon. This negative energy can balance the positive energy needed to create matter, but it’s not quite that simple. The negative gravitational energy of the earth, for example, is less than a billionth of the positive energy of the matter particles the earth is made of. A body such as a star will have more negative gravitational energy, and the smaller it is (the closer the different parts of it are to each other), the greater the negative gravitational energy will be. But before it can become greater than the positive energy of the matter, the star will collapse to a black hole, and black holes have positive energy. That’s why empty space is stable. Bodies such as stars or black holes cannot just appear out of nothing. But a whole universe can." Stephen Hawking, The Grand Design, p. 180. The concept that the total net energy is zero or close to zero seems to be widely accepted. Hawking states it like it is a law, others do not. I believe it was Paul Davies who said it was estimated to be within one percent of zero or something like that. Then, we have this comment on youtube from Larry Krauss. https://www.youtube.com/watch?v=NfOL_oGgRVk Even though this concept seems to be widely accepted, I am extremely skeptical. If I am wrong, I hope someone can convince me. Here are the facts as I see them. Please correct me where I'm wrong. I understand that gravitational field energy can be negative, but the gravitational field energy between the earth and the moon is very small compared to the positive energy of the matter particles. Hawking says it less than a billionth of the positive energy. When can gravitational field energy be greater than the positive energy of the matter? If I read Hawking correctly, not until the matter is so dense it is a black hole. The entire universe would have to be a black hole for the net energy to be zero. Second, there is nothing to offset the positive heat energy of the universe. The cosmic microwave background radiation is only ~2.7 kelvin, so not much above absolute zero - but there is no way to go below absolute zero. Plus we have the heat output of all the stars in the universe. Third, the universe is expanding at an accelerating rate. Theorists are postulating some type of "antigravity force" at work called dark energy. If a gravitational field has negative energy, then dark energy must be positive energy. Since the expansion is accelerating, the antigravity energy must be greater than the gravitational energy. Someone is wrong here. Either it is Hawking, Krauss and Davies or it is me. Modesty would indicate it is probably me. What am I missing? Edited by Admin, : Add moderator note.
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Admin Director Posts: 13100 From: EvC Forum Joined: |
Hi DesignTheorist,
I think a debate about whether the universe has zero net energy that is based upon evidence would be great. I could consider promoting the thread if you can eliminate the parts of the proposal that might drag the thread into a discussion of whose quote means what, such as this:
designtheorist writes: Someone is wrong here. Either it is Hawking, Krauss and Davies or it is me.
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designtheorist Member (Idle past 4025 days) Posts: 390 From: Irvine, CA, United States Joined:
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As I was reading The Grand Design by Stephen Hawking, I came across this passage:
"If the total energy of the universe must always remain zero, and it costs energy to create a body, how can a whole universe be created from nothing? That is why there is a law like gravity. Because gravity is attractive, gravitational energy is negative: One has to do work to separate a gravitationally bound system, such as the earth and moon. This negative energy can balance the positive energy needed to create matter, but it’s not quite that simple. The negative gravitational energy of the earth, for example, is less than a billionth of the positive energy of the matter particles the earth is made of. A body such as a star will have more negative gravitational energy, and the smaller it is (the closer the different parts of it are to each other), the greater the negative gravitational energy will be. But before it can become greater than the positive energy of the matter, the star will collapse to a black hole, and black holes have positive energy. That’s why empty space is stable. Bodies such as stars or black holes cannot just appear out of nothing. But a whole universe can." Stephen Hawking, The Grand Design, p. 180. Joseph Silk, an astronomer at Oxford in a review of Hawking's book, wrote:"Gravity accounts for negative energy, whereas the mass of a star is undeniably positive. On large enough scales, once one counts all the black holes, stars, and empty space, the overall energy of the universe is close to zero (as measured). If the universe has zero energy, then it could have been spontaneously created from nothing by quantum fluctuations." Just a moment... The concept that the total net energy is zero or close to zero seems to be widely accepted. Hawking states it like it is a law, others do not. I believe it was Paul Davies who said it was estimated to be within one percent of zero or something like that. Then, we have this comment on youtube from Larry Krauss. https://www.youtube.com/watch?v=NfOL_oGgRVk Even though the concept seems accepted by leading authors, I am extremely skeptical. If I am wrong, I hope someone can convince me. Here are the facts as I see them. I understand that gravitational field energy can be described as negative, but the gravitational field energy between the earth and the moon is very small compared to the positive energy of the matter particles. Hawking says it less than a billionth of the positive energy. When can gravitational field energy be greater than the positive energy of the matter? If I read Hawking correctly, not until the matter is so dense it is a black hole. The entire universe would have to be a black hole for the net energy to be zero. Second, negative heat energy does not exist. There is nothing to offset the positive heat energy of the universe. The cosmic microwave background radiation is only ~2.7 kelvin, so not much above absolute zero - but there is no way to go below absolute zero. Plus we have the heat output of all the stars in the universe. Third, the universe is expanding at an accelerating rate. Theorists postulate an "antigravity force" at work called dark energy. If a gravitational field has negative energy, then the antigravity force of dark energy must be positive energy. Since the expansion is accelerating, the antigravity energy must be greater than the gravitational energy. Fourth, negative energy densities may exist according to quantum field theory but this is negligible and described in the literature as "potentially observable," so I doubt this was even considered in the calculations leading to the view of zero total energy. Can anyone convince me I'm wrong?
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designtheorist Member (Idle past 4025 days) Posts: 390 From: Irvine, CA, United States Joined: |
I have sent emails to Paul Davies and Joseph Silk to ask for their comments (or for them to comment on this forum).
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Admin Director Posts: 13100 From: EvC Forum Joined:
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Hi DesignTheorist,
I don't think you understand what I'm trying achieve. I'd like to avoid having discussion threads that turn into arguments about what someone thinks or what their quotes mean. My goal is discussions of the evidence. This means that for purposes of discussion I don't care what Hawking or Davies or Silk or Krauss think the data means. I want people to discuss the data and render their own interpretations of what it means. Your proposal in Message 1 did a good of doing that, except that it left the door wide open to arguments about quotes. If you can close that door I can consider promoting the thread.
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designtheorist Member (Idle past 4025 days) Posts: 390 From: Irvine, CA, United States Joined: |
You're right. I didn't understand. I'm still not certain I understand. Are you asking me to remove quotes from the OP?
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Admin Director Posts: 13100 From: EvC Forum Joined: |
There's nothing wrong with quotes. Frequently the words of our best minds are the best way to make a point or explain something complex.
But I fear you're making quotes the central focus of discussion when they should play only a supporting role. This fear springs from when you present some quotes and then say something like, "I want to know who's wrong here, Krauss, Davies, Silk or Hawking." Presentation and interpretation of the evidence should be the main focus.
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designtheorist Member (Idle past 4025 days) Posts: 390 From: Irvine, CA, United States Joined: |
Perhaps I was not clear. I am using the quotes to present the evidence from the side I don't agree with. All of the authors (Hawking, Silk, Davies and Krauss) are on the same side. i asked if the authors were wrong or me.
I quoted Hawking because he provides the ratio of gravitational energy to the energy of earth's matter. But Hawking also did something unusual in that he presented the zero total energy idea like it was a law. Silk presents it like it is the result of measurement/estimation which is more usual. But Hawking and Silk do not disagree with each other. I, on the other hand, would think the idea completely laughable if not for the fact so many people think it is true. So I presented my evidence after presenting the evidence from the authors. At this point, I'm uncertain what I can do to make the OP acceptable to you. Let me know what you would like me to change and I will try again. Edited by designtheorist, : Clarification
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Admin Director Posts: 13100 From: EvC Forum Joined: |
Hi DesignTheorist,
You're right, I misunderstood. I thought you had arrived at interpretations of Hawking, Davies, Krauss and Silk that had them at odds with each other. It doesn't actually matter to me whether they agree or not, I just didn't want to open a thread arguing about the meaning of quotes from famous physicists. I see where you're going now and think it would make a great thread. If you give me the okay I'll make a few edits to your opening post just to make sure no one arrives at the same misinterpretation I did.
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designtheorist Member (Idle past 4025 days) Posts: 390 From: Irvine, CA, United States Joined: |
I was in a rush when I first wrote the OP. Let me try one more time. If you still think it needs editing, feel free.
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designtheorist Member (Idle past 4025 days) Posts: 390 From: Irvine, CA, United States Joined: |
About a year ago I came across a Larry Krauss video clip explaining the concept of zero total net energy in the universe at
https://www.youtube.com/watch?v=NfOL_oGgRVk When I first watched the clip, I laughed out loud. I thought "Larry's lost it! No one is going to believe the net energy in the universe is zero or even close to zero!" I was surprised to find out the viewpoint is actually quite common. In The Grand Design, Stephen Hawking writes:"If the total energy of the universe must always remain zero, and it costs energy to create a body, how can a whole universe be created from nothing? That is why there is a law like gravity. Because gravity is attractive, gravitational energy is negative: One has to do work to separate a gravitationally bound system, such as the earth and moon. This negative energy can balance the positive energy needed to create matter, but it’s not quite that simple. The negative gravitational energy of the earth, for example, is less than a billionth of the positive energy of the matter particles the earth is made of. A body such as a star will have more negative gravitational energy, and the smaller it is (the closer the different parts of it are to each other), the greater the negative gravitational energy will be. But before it can become greater than the positive energy of the matter, the star will collapse to a black hole, and black holes have positive energy. That’s why empty space is stable. Bodies such as stars or black holes cannot just appear out of nothing. But a whole universe can." Stephen Hawking, The Grand Design, p. 180. This is a valuable passage because Hawking gives us a couple of examples of the ratio of energy from particle matter to negative energy from the gravitational field. But Hawking speaks of the zero net energy like it is a given or a law. This is unusual. Most authors speak of it like both the positive and negative energy has been measured/estimated and the total is zero or very close to zero. In a review of Hawking's The Grand Design, Joseph Silk, an astronomer at Oxford, wrote:"Gravity accounts for negative energy, whereas the mass of a star is undeniably positive. On large enough scales, once one counts all the black holes, stars, and empty space, the overall energy of the universe is close to zero (as measured). If the universe has zero energy, then it could have been spontaneously created from nothing by quantum fluctuations." Just a moment... So Krauss, Hawking, Silk, Davies - all of the leading authors in physics and astronomy - seem to agree that the net total energy for the universe is zero or close to zero. I am extremely skeptical of this. The total net energy of the universe looks to be strongly, strongly positive. Here are the facts as I see them. I understand that gravitational field energy can be negative, but the gravitational field energy between the earth and the moon is very small compared to the positive energy of the matter particles. Hawking says it less than a billionth of the positive energy. When can gravitational field energy be greater than the positive energy of the matter? If I read Hawking correctly, not until the matter is so dense it is a black hole. The entire universe would have to be a black hole for the net energy to be zero. Second, there is nothing to offset the positive heat energy of the universe. In addition to the heat output from all the stars, we have the cosmic microwave background radiation. CMB radiation is only ~2.7 kelvin, so not much above absolute zero - but when spread out over billions of light years in every direction - that's a lot of joules! Plus, there is no way to go below absolute zero. You cannot have negative thermal energy. Third, the universe is expanding at an accelerating rate. Theorists are postulating some type of "antigravity force" at work called dark energy. If a gravitational field has negative energy, then dark energy must be positive energy. Since the expansion is accelerating, the antigravity energy must be greater than the gravitational energy. The WMAP Project claims to have measured the amount of dark energy. "WMAP's accuracy and precision determined that dark energy makes up 72.1% of the universe (to within 1.5%), causing the expansion rate of the universe to speed up. - 'Lingering doubts about the existence of dark energy and the composition of the universe dissolved when the WMAP satellite took the most detailed picture ever of the cosmic microwave background (CMB).'"Wilkinson Microwave Anisotropy Probe (WMAP) Either Krauss, Hawking, Silk and Davies are all correct or I am. Modesty would suggest I am probably in the wrong. If so, explain it to me. What am I missing? Edited by designtheorist, : Clarification Edited by designtheorist, : Clarification
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Admin Director Posts: 13100 From: EvC Forum Joined: |
Thread copied to the Does the universe have total net energy of zero? thread in the Big Bang and Cosmology forum, this copy of the thread has been closed.
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