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Author Topic:   Does the universe have total net energy of zero?
Modulous
Member (Idle past 1091 days)
Posts: 7789
From: Manchester, UK
Joined: 05-01-2005


Message 23 of 404 (643701)
12-10-2011 2:12 PM
Reply to: Message 22 by designtheorist
12-10-2011 1:15 PM


Re: Is the total net energy in the universe zero?
I'm not a physicist, and I can't offer you a persuasive paper. I can offer a badly designed home webpage of a physics tutor which gives back of an envelope calculations. See here

To summarize

positive energy content = mc2
negative energy content = m Mu G / R u

The little m's can be ignored so now we get

positive = c2
negative = Mu G / R u

All you need to do is know the speed of light, the mass and radius of the universe and the gravitational constant. The web page gives some numbers for this and we end up with

positive energy = 9 x 1016
negative energy = - 9.77 x 1016

And so positive energy ≈ -negative energy. Obviously we don't know the exact radius and mass of the universe so it seems reasonable to consider the possibility that it balances out equally.

Of course I need to repeat my non-physicist status so that might all be bollocks but it is the most accessible resource for explaining this that I can find. Physics papers tend to give more complex, but probably more accurate, descriptions - for example:

ON THE ZERO-ENERGY UNIVERSE, Berman, 2009

quote:
The zero result for the spatial components of the energy-momentum-pseudotensor calculation,
are equivalent to the choice of a center of Mass reference system in Newtonian theory,
likewise the use of comoving observers in Cosmology. It is with this idea in mind, that we are
led to the energy calculation, yielding zero total energy, for the Universe, as an acceptable
result: we are assured that we chose the correct reference system

Hope that proves to be of use, but I've no idea if it'll prove 'persuasive' to you.

Edited by Modulous, : No reason given.


This message is a reply to:
 Message 22 by designtheorist, posted 12-10-2011 1:15 PM designtheorist has responded

Replies to this message:
 Message 25 by designtheorist, posted 12-10-2011 11:49 PM Modulous has responded
 Message 26 by designtheorist, posted 12-11-2011 12:17 AM Modulous has responded

  
Modulous
Member (Idle past 1091 days)
Posts: 7789
From: Manchester, UK
Joined: 05-01-2005


Message 30 of 404 (643728)
12-11-2011 3:38 AM
Reply to: Message 25 by designtheorist
12-10-2011 11:49 PM


pseudo tensors
A quick reading of the paper did not convince me the author is correct. For one thing, I'm not sure what pseudo-tensors are or how they might be helpful in estimating total net energy.

I can see why not understanding the physics could render the paper unpersuasive to you. I propose that given that you don't know what a pseudo-tensor is, that this topic may simply be beyond your expertise to fully grasp.


This message is a reply to:
 Message 25 by designtheorist, posted 12-10-2011 11:49 PM designtheorist has responded

Replies to this message:
 Message 31 by Chuck77, posted 12-11-2011 4:19 AM Modulous has responded
 Message 41 by designtheorist, posted 12-11-2011 11:22 AM Modulous has acknowledged this reply

  
Modulous
Member (Idle past 1091 days)
Posts: 7789
From: Manchester, UK
Joined: 05-01-2005


Message 32 of 404 (643731)
12-11-2011 4:25 AM
Reply to: Message 31 by Chuck77
12-11-2011 4:19 AM


Re: pseudo tensors
It's beyond me. Can you simplify it some?

It's beyond me too, so no I can't.

What is negative energy compared to positive energy in the universe mean?

As far as I can tell negative energy is related to the gravitational field. Positive energy is energy as we generally use it.

Do some physicists say all the matter energy cancels eachother out therefore zero?

Not quite. They say the positive energy content of the universe is essentially cancelled out by the negative energy content of the universe.

Edited by Modulous, : No reason given.


This message is a reply to:
 Message 31 by Chuck77, posted 12-11-2011 4:19 AM Chuck77 has responded

Replies to this message:
 Message 33 by Chuck77, posted 12-11-2011 4:30 AM Modulous has responded

  
Modulous
Member (Idle past 1091 days)
Posts: 7789
From: Manchester, UK
Joined: 05-01-2005


Message 69 of 404 (643786)
12-11-2011 7:17 PM
Reply to: Message 26 by designtheorist
12-11-2011 12:17 AM


Re: Is the total net energy in the universe zero?
Not true. The m is not a hypothetical particle; the m stands for mass.

I think it's safe to say that the author knows what m stands for. A superior argument would be that the m in the first equation is referring to something subtly different than the m in the second equation.

What you really probably should be saying is that the m in Einstein's equation is really the same as Mu in the gravitational equation when we're talking about energy content of the entire universe.

I believe that in the gravitational equation, when M is actually Mu then I'm not sure m is actually the mass of. This may be what is being said when he talks of it being hypothetical. But I don't think it's hypothetical in both equations and that might be where the problem is.

As far as my limited physics knowledge goes the gravitation equation calculates the gravitational energy between two masses. So maybe the thought is that when calculating the gravitational energy of the universe it has to be compared with the mass of a hypothetical particle.

Those were my thoughts at least, when I hinted that the calculations might be bollocks.

Einstein's equation for calculating how much energy you can get from matter or how much matter you can get from energy.

I assume you misspoke here. It's not a matter/energy equivalence its a mass/energy equivalence.


This message is a reply to:
 Message 26 by designtheorist, posted 12-11-2011 12:17 AM designtheorist has responded

Replies to this message:
 Message 72 by designtheorist, posted 12-11-2011 7:29 PM Modulous has acknowledged this reply

  
Modulous
Member (Idle past 1091 days)
Posts: 7789
From: Manchester, UK
Joined: 05-01-2005


Message 89 of 404 (643872)
12-12-2011 1:35 PM
Reply to: Message 33 by Chuck77
12-11-2011 4:30 AM


positive and negative
Ok, but there is still energy right?

Right.

A neutron is made of an up quark which has a charge of +2/3e and two down quarks each with a charge of -1/3e.

There is charge, but a neutron has no net charge.

Im just not sure the theme is supposed to be, what the thread means. Zero energy or infinate energy, what means what?

The idea is that the energy is comprised of negative and positive energy. The question is, what is the net result of those negatives and positives in the universe at large? Some physicists believe that the net result is zero, just as with the charges in the neutron.


This message is a reply to:
 Message 33 by Chuck77, posted 12-11-2011 4:30 AM Chuck77 has not yet responded

Replies to this message:
 Message 92 by designtheorist, posted 12-12-2011 2:00 PM Modulous has responded

  
Modulous
Member (Idle past 1091 days)
Posts: 7789
From: Manchester, UK
Joined: 05-01-2005


Message 91 of 404 (643875)
12-12-2011 1:48 PM
Reply to: Message 81 by designtheorist
12-12-2011 1:40 AM


the mass of energy
But dark energy is different. It is an anti-gravity force.

I don't think that's quite right. It certainly acts against gravity, but so do rockets.

quote:
This accelerating expansion effect is sometimes labeled "gravitational repulsion", which is a colorful but possibly confusing expression. In fact a negative pressure does not influence the gravitational interaction between masses—which remains attractive—but rather alters the overall evolution of the universe at the cosmological scale, typically resulting in the accelerating expansion of the universe despite the attraction among the masses present in the universe.

from wiki.


Dark energy (74%) and not enough gravity to cancel it out.

Of course, this ignores other types of energy in the universe such as thermal energy and kinetic energy of galaxies which shows the net total energy to be even more positive.

Have you calculated the gravitational effect of the other types of energy? Have you calculated it for dark energy?

Remember energy and mass are equivalent. So energy has an associated mass just like mass has an associated energy. Where there is mass there is gravity. The negative pressure of dark energy may be greater than the associated gravity its mass produces, but that doesn't mean that the negative energy isn't cancelled out by the positive energy.


This message is a reply to:
 Message 81 by designtheorist, posted 12-12-2011 1:40 AM designtheorist has not yet responded

  
Modulous
Member (Idle past 1091 days)
Posts: 7789
From: Manchester, UK
Joined: 05-01-2005


Message 93 of 404 (643877)
12-12-2011 2:11 PM
Reply to: Message 92 by designtheorist
12-12-2011 2:00 PM


Re: positive and negative
What is being discussed has nothing at all to do with the charge or even the spin of particles.

It was an analogy designed to show how something can have a net zero value while being composed of positive and negative values.

The negative energy comes from the gravitational field.

Which is why I said in Message 32 that

quote:
negative energy is related to the gravitational field. Positive energy is energy as we generally use it.

But this confused Chuck and he replied

Chuck writes:

Ok, but there is still energy right?

I was attempting to show him how there can still be (positive) energy even if the net energy is zero. I used the analogy of charge. Dr A used the analogy of mutual debt in Message 35. Can you come up with a better analogy to explain it to Chuck?


This message is a reply to:
 Message 92 by designtheorist, posted 12-12-2011 2:00 PM designtheorist has responded

Replies to this message:
 Message 99 by designtheorist, posted 12-12-2011 3:32 PM Modulous has acknowledged this reply

  
Modulous
Member (Idle past 1091 days)
Posts: 7789
From: Manchester, UK
Joined: 05-01-2005


Message 148 of 404 (644598)
12-19-2011 12:27 PM
Reply to: Message 142 by designtheorist
12-17-2011 4:23 PM


Re: Is net zero energy universe "not even wrong?"
Perhaps the theory was viable at that point (I don't think so) but how can the theory still be viable after the discovery of the anti-gravity force of dark energy and the accelerating universe?

Because dark energy has negative energy associated with it because as far as I know it has an associated mass that 'creates' a gravitational field. The zero energy postulate suggests that the negative energy as the result of the gravitational field cancels out the positive energy content of the stuff in question.

Is your problem with this that you do not think that dark energy has an associated mass? Do you have any sources which indicate that dark energy is massless?

The fact that dark energy has negative pressure which acts against gravity is irrelevant.


This message is a reply to:
 Message 142 by designtheorist, posted 12-17-2011 4:23 PM designtheorist has responded

Replies to this message:
 Message 150 by designtheorist, posted 12-19-2011 1:20 PM Modulous has responded

  
Modulous
Member (Idle past 1091 days)
Posts: 7789
From: Manchester, UK
Joined: 05-01-2005


Message 152 of 404 (644611)
12-19-2011 1:40 PM
Reply to: Message 150 by designtheorist
12-19-2011 1:20 PM


Re: Is net zero energy universe "not even wrong?"
We really don't know a lot about dark energy except that it has an antigravitational effect.

Rather, it has a negative pressure.

Is it your view dark energy can be converted into dark matter in the same way ordinary energy can be converted into ordinary matter?

No, you are confusing matter and mass. Energy has an associated mass. I see no reason to suppose that Dark Energy does not have an associated mass. Do you have one?

This would be unusual because dark matter has normal gravity and dark energy is antgravitational.

My point is that dark energy may also have normal gravity. Just because it exerts a negative pressure that acts against gravity, does not mean that it is massless and does not have an associated gravitational field.

No. This is the point. Gravity is not the all-powerful cosmic force we once thought. On a cosmic scale, anti-gravity is more powerful than gravity.

It's not anti-gravity it is a negative pressure that acts against gravity in the evolution of the cosmos. I quote wikipedia again

quote:
This accelerating expansion effect is sometimes labeled "gravitational repulsion", which is a colorful but possibly confusing expression. In fact a negative pressure does not influence the gravitational interaction between masses—which remains attractive—but rather alters the overall evolution of the universe at the cosmological scale, typically resulting in the accelerating expansion of the universe despite the attraction among the masses present in the universe.

Negative pressure is not 'anti gravity' in the technical sense (which may require negative mass) - only in a colloquial sense. It's easy to get confused on that, though.


This message is a reply to:
 Message 150 by designtheorist, posted 12-19-2011 1:20 PM designtheorist has responded

Replies to this message:
 Message 153 by designtheorist, posted 12-19-2011 2:52 PM Modulous has acknowledged this reply

  
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