Understanding through Discussion


Welcome! You are not logged in. [ Login ]
EvC Forum active members: 61 (9042 total)
93 online now:
DrJones*, ICANT (2 members, 91 visitors)
Newest Member: maria
Post Volume: Total: 886,022 Year: 3,668/14,102 Month: 288/321 Week: 104/44 Day: 20/26 Hour: 0/0


Thread  Details

Email This Thread
Newer Topic | Older Topic
  
Author Topic:   Does the universe have total net energy of zero?
subbie
Member (Idle past 193 days)
Posts: 3509
Joined: 02-26-2006


Message 166 of 404 (644658)
12-19-2011 8:03 PM
Reply to: Message 164 by designtheorist
12-19-2011 7:32 PM


Re: Is net zero energy universe "not even wrong?"
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


This message is a reply to:
 Message 164 by designtheorist, posted 12-19-2011 7:32 PM designtheorist has responded

Replies to this message:
 Message 171 by designtheorist, posted 12-19-2011 10:58 PM subbie has responded

  
Admin
Director
Posts: 12719
From: EvC Forum
Joined: 06-14-2002


Message 167 of 404 (644660)
12-19-2011 8:53 PM


Moderator Request
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.


--Percy
EvC Forum Director

  
kbertsche
Member (Idle past 1069 days)
Posts: 1427
From: San Jose, CA, USA
Joined: 05-10-2007


Message 168 of 404 (644662)
12-19-2011 9:20 PM
Reply to: Message 165 by designtheorist
12-19-2011 7:38 PM


Re: On the nature of negative gravitational energy – Part I
quote:
Can you please explain this portion for me?
quote:
Part (b) shows how energy can be extracted as the shell is allowed to uniformly contract. Each piece of the shell is tied by a rope to an electrical generator, producing power as the piece is “lowered” toward its final position.

How is energy extracted? What effect does the rope have when "tied" to an electrical generator? Isn't there an energy output in "allowing" the mass to uniformly contract?


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


This message is a reply to:
 Message 165 by designtheorist, posted 12-19-2011 7:38 PM designtheorist has responded

Replies to this message:
 Message 169 by designtheorist, posted 12-19-2011 10:28 PM kbertsche has not yet responded
 Message 177 by designtheorist, posted 12-20-2011 12:03 PM kbertsche has responded

  
designtheorist
Member (Idle past 2771 days)
Posts: 390
From: Irvine, CA, United States
Joined: 09-15-2011


Message 169 of 404 (644668)
12-19-2011 10:28 PM
Reply to: Message 168 by kbertsche
12-19-2011 9:20 PM


Re: On the nature of negative gravitational energy – Part I
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.


This message is a reply to:
 Message 168 by kbertsche, posted 12-19-2011 9:20 PM kbertsche has not yet responded

  
designtheorist
Member (Idle past 2771 days)
Posts: 390
From: Irvine, CA, United States
Joined: 09-15-2011


Message 170 of 404 (644669)
12-19-2011 10:43 PM


Is negative energy a mathematical convention or something different?
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?


Replies to this message:
 Message 178 by kbertsche, posted 12-20-2011 12:04 PM designtheorist has not yet responded

  
designtheorist
Member (Idle past 2771 days)
Posts: 390
From: Irvine, CA, United States
Joined: 09-15-2011


Message 171 of 404 (644670)
12-19-2011 10:58 PM
Reply to: Message 166 by subbie
12-19-2011 8:03 PM


Re: Is net zero energy universe "not even wrong?"
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.


This message is a reply to:
 Message 166 by subbie, posted 12-19-2011 8:03 PM subbie has responded

Replies to this message:
 Message 172 by subbie, posted 12-19-2011 11:34 PM designtheorist has responded

  
subbie
Member (Idle past 193 days)
Posts: 3509
Joined: 02-26-2006


Message 172 of 404 (644672)
12-19-2011 11:34 PM
Reply to: Message 171 by designtheorist
12-19-2011 10:58 PM


Re: Is net zero energy universe "not even wrong?"
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


This message is a reply to:
 Message 171 by designtheorist, posted 12-19-2011 10:58 PM designtheorist has responded

Replies to this message:
 Message 173 by designtheorist, posted 12-19-2011 11:47 PM subbie has acknowledged this reply

  
designtheorist
Member (Idle past 2771 days)
Posts: 390
From: Irvine, CA, United States
Joined: 09-15-2011


Message 173 of 404 (644676)
12-19-2011 11:47 PM
Reply to: Message 172 by subbie
12-19-2011 11:34 PM


Reply to subbie
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.


This message is a reply to:
 Message 172 by subbie, posted 12-19-2011 11:34 PM subbie has acknowledged this reply

  
Admin
Director
Posts: 12719
From: EvC Forum
Joined: 06-14-2002


Message 174 of 404 (644705)
12-20-2011 7:25 AM


Closing this thread for 4 hours
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.


--Percy
EvC Forum Director

  
Admin
Director
Posts: 12719
From: EvC Forum
Joined: 06-14-2002


Message 175 of 404 (644737)
12-20-2011 11:28 AM


This thread now open
Please follow the moderator requests in the previous message. Thanks.

--Percy
EvC Forum Director

  
kbertsche
Member (Idle past 1069 days)
Posts: 1427
From: San Jose, CA, USA
Joined: 05-10-2007


Message 176 of 404 (644741)
12-20-2011 11:58 AM
Reply to: Message 137 by designtheorist
12-17-2011 2:18 PM


Re: On the nature of negative gravitational energy – Part I
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:
Part (a) is a three-dimensional sphere, represented in Figure A2 as a large circle. The gravitational field lines pointing at the circle end at the point of the circle. They do not proceed to the center of the hollow sphere.

Part (b) is a somewhat smaller circle (intermediate-sized) circle. Outside of the circle are figures representing ropes and generators. This is the stage at which energy is extracted.

Part (c) shows a smaller circle. The ropes and generators are gone. The original larger circle is represented by a dotted line. The area between the smaller circle and the dotted circle is shaded. The gravitational lines now extend past the dotted circle and stop at the smaller circle.

According to Dr. Guth, energy is extracted and the gravitational field is enlarged and together this proves gravitational field energy is negative. Really, Dr. Guth?



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:
According to this thinking, the smallest particle would have the largest gravitational field.

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:
Perhaps I am missing the point, but let’s examine this. It appears that energy is extracted from the hollow shell of mass by reducing the size of the mass. If one reduces the mass, then the strength of the gravitational field is reduced. The fact the region of the field is increased is meaningless.

No, the volume is reduced, but the mass remains fixed. The mass does not reduce.

quote:
None of these illustrations or descriptions of gravity show persuasively that gravitational energy is negative.

Then you haven't quite grasped the arguments yet. Guth's and wikipedia's arguments should be persuasive.

quote:
But even if they did, all the illustrations are dealing with local effects. Everyone agrees that the local effects of gravity are about one-billionth of the positive energy of the local mass.

If the universe-wide effects of gravitational energy are so strongly negative, where are the illustrations and descriptions of that negative energy?



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


This message is a reply to:
 Message 137 by designtheorist, posted 12-17-2011 2:18 PM designtheorist has not yet responded

  
designtheorist
Member (Idle past 2771 days)
Posts: 390
From: Irvine, CA, United States
Joined: 09-15-2011


Message 177 of 404 (644743)
12-20-2011 12:03 PM
Reply to: Message 168 by kbertsche
12-19-2011 9:20 PM


Reply to kbertsche
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.


This message is a reply to:
 Message 168 by kbertsche, posted 12-19-2011 9:20 PM kbertsche has responded

Replies to this message:
 Message 179 by kbertsche, posted 12-20-2011 12:12 PM designtheorist has not yet responded

  
kbertsche
Member (Idle past 1069 days)
Posts: 1427
From: San Jose, CA, USA
Joined: 05-10-2007


Message 178 of 404 (644744)
12-20-2011 12:04 PM
Reply to: Message 170 by designtheorist
12-19-2011 10:43 PM


Re: Is negative energy a mathematical convention or something different?
quote:
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?


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


This message is a reply to:
 Message 170 by designtheorist, posted 12-19-2011 10:43 PM designtheorist has not yet responded

  
kbertsche
Member (Idle past 1069 days)
Posts: 1427
From: San Jose, CA, USA
Joined: 05-10-2007


Message 179 of 404 (644746)
12-20-2011 12:12 PM
Reply to: Message 177 by designtheorist
12-20-2011 12:03 PM


Re: Reply to kbertsche
quote:

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.


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


This message is a reply to:
 Message 177 by designtheorist, posted 12-20-2011 12:03 PM designtheorist has not yet responded

  
NoNukes
Inactive Member


Message 180 of 404 (644752)
12-20-2011 12:45 PM
Reply to: Message 141 by designtheorist
12-17-2011 3:59 PM


Re: A Simple Thought Experiment
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:
The "acceleration" (or reduced deceleration) of the expansion of the Cosmos is caused by the expansive entropic property (intrinsic dimensional motion) of light, combined with a reduction of the total gravitational energy of the Cosmos. This expansive combination is the "dark energy" or "cosmological constant" producing the observed acceleration (which should have been anticipated if we had realized that light does not produce a gravitational field).

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.


This message is a reply to:
 Message 141 by designtheorist, posted 12-17-2011 3:59 PM designtheorist has responded

Replies to this message:
 Message 188 by designtheorist, posted 12-20-2011 10:00 PM NoNukes has responded

  
Newer Topic | Older Topic
Jump to:


Copyright 2001-2018 by EvC Forum, All Rights Reserved

™ Version 4.0 Beta
Innovative software from Qwixotic © 2021