# Thread: Negative Mass

1. ## Negative Mass

I think there is negative mass in the universe. Like negative charge. The difference between charges and mass being that Like charges repel but like masses attract. Unlike masses(opposite signs ) repel. Positive mass and negative mass annihilate when they collide, just like charges.

When the Universe was created, Positive and negative mases repelled and got seperated. negative mass in a cluster of Positive mass got annihilated. thats the reason why we dont observe any negative mass around us

What do you think about this theory? Any comment for/against it are welcome.

2. Is there any negative mass in the universe? Well, none that has been observed. But it is certainly considered theoretically possible, now.

And interestingly, at first blush, as you are thinking, you would think that + and - mass would work just like Maxwell with a minus sign. Like masses attract, while opposites repel. Well, the Equivalence Principle and General Relativity have something different to say about that. It gets very weird.

Negative mass must have negative inertia. And that means, you get another minus sign. Positive mass will attract all mass, both positive and negative, and negative mass will repel all other mass, positive included.

With Newton, that would mean that if you placed two equal and opposite masses some distance apart, they both would accelerate off, maintaing constant distance between them. That's just, well, weird. Doesn't violate any conservation laws, but is just plain weird.

Now, that's Newton. Do some General Relativity, and that situation leads to a type of "warp drive". Only problem is you need several solar masses worth of negative mass.

Now, it used be though that negative mass-energy was just impossible, but quantum theory is saying it might not be some impossible.

-Richard

3. E = mc^2

E (energy) is always positive; c^2 is always positive; ergo: m is always positive.

Or was Einstein wrong?

4. Originally Posted by Peter Wilson
E = mc^2

E (energy) is always positive; c^2 is always positive; ergo: m is always positive.

Or was Einstein wrong?
I don't think Einstein ever claimed that E is always positive, though c^2, being constant, is just as positive in any situation as in any other. Energy is relative anyway (the nearest-equivalent "absolute" quantity being four-momentum) so I doubt Einstein would require it to always be positive. (edit to add e.g. I think that an ice cube could be considered to have negative energy with respect to your hand, hence, your hand loses heat energy to the ice cube if you hold it.

On the other hand, I do believe there is a theoretical "negative energy" which is essentially the same as "exotic matter" of negative mass. Ken Thorpe in "Black Holes and Time Warps: Einstein's Outrageous Legacy" says this exotic mass could be used to prop a wormhole open, assuming wormholes and exotic mass both exist.

5. This brings up an important point about General Relativity. There are a lot of things GR allows but are thought to be unphysical (that is other physics disallows it).

Again, GR allows negative mass-energy, and that was one of those things thought to be unphysical by other physics, but quantum theory seems to give it some reality now.

There are other things as well. There are what they call "energy conditions", which are restrictions on the stress-energy tensor source terms. These are statements, outside of GR, about what mass-energy can do so to speak. Many of these are not proven, just "thought to be so", because things would be so weird if they didn't hold.

And finally, I think even the "arrow of time" is not specified by GR. There are "time running backwards" solutions (this gets well beyond my own understanding and so I'm not really confident to say much), sort of where things can run backwards along their world lines. Those are rejected by the "time runs foward" condition that is added on.

-Richard

6. The collapse of the wave-function in QM provides a one-way "diode" for time. This is "built in," not added on.

7. Originally Posted by Peter Wilson
The collapse of the wave-function in QM provides a one-way "diode" for time. This is "built in," not added on.
It is said often that GR and QM are incompatible. There are professionals on both sides of the debate. The professionals on each side of the debate are saying that the professionals on the other side are wrong. They could both be right about that.

8. Join Date
Apr 2007
Posts
6
Thankfully, none of you are physicists. Please keep it that way.

9. Wow, what brought that on? Welcome to the board, I guess.

10. Order of Kilopi
Join Date
May 2004
Posts
4,139
It's probably worth mentioning that people have also considered imaginary rest masses as well. I attended a colloquium in the early '90s where a guy was presenting an analysis of values for the mass of the neutrino. At the time what was measurable was the square of the rest mass, and the weighted mean value (derived from all the attempts at measurement) came out to be negative. Normally people assumed that the value should be real and hence the part of the error distribution below zero was chopped off. This guy, on the other hand, was looking at the consequences of a negative value of m2, i.e an imaginary rest mass for the neutrino. The most obvious being the implication that the neutrino was a tachyon.

Of course, since then we now have good evidence that the neutrino possesses a real, and non-negative, rest mass. Even so it is fun to follow these things through.

11. Order of Kilopi
Join Date
Mar 2004
Posts
13,441
Originally Posted by Samba
I think there is negative mass in the universe. Like negative charge. The difference between charges and mass being that Like charges repel but like masses attract. Unlike masses(opposite signs ) repel. Positive mass and negative mass annihilate when they collide, just like charges.

When the Universe was created, Positive and negative mases repelled and got seperated. negative mass in a cluster of Positive mass got annihilated. thats the reason why we dont observe any negative mass around us

What do you think about this theory? Any comment for/against it are welcome.
You called this a "theory"; do you mean 'theory' as in 'speculative idea', 'guess'? Or as in 'scientific theory'?

If the latter, then can you give some references, to papers published in the relevant peer-reviewed literature, on it?

12. Originally Posted by Stopbeingdumbeverybody
Thankfully, none of you are physicists. Please keep it that way.
Welcome? It is my understanding that there are many physicists on the boards. Also many engineers. And astronomers. And mathematicians. Hang out a while, you'll figure out who's who.

13. Originally Posted by publius
Is there any negative mass in the universe? Well, none that has been observed. But it is certainly considered theoretically possible, now.

And interestingly, at first blush, as you are thinking, you would think that + and - mass would work just like Maxwell with a minus sign. Like masses attract, while opposites repel. Well, the Equivalence Principle and General Relativity have something different to say about that. It gets very weird.

Negative mass must have negative inertia. And that means, you get another minus sign. Positive mass will attract all mass, both positive and negative, and negative mass will repel all other mass, positive included.

With Newton, that would mean that if you placed two equal and opposite masses some distance apart, they both would accelerate off, maintaing constant distance between them. That's just, well, weird. Doesn't violate any conservation laws, but is just plain weird.

Now, that's Newton. Do some General Relativity, and that situation leads to a type of "warp drive". Only problem is you need several solar masses worth of negative mass.

Now, it used be though that negative mass-energy was just impossible, but quantum theory is saying it might not be some impossible.

-Richard
Well thats just what I thought initially. I didnt think it could get so complicated.

14. Originally Posted by Nereid
You called this a "theory"; do you mean 'theory' as in 'speculative idea', 'guess'? Or as in 'scientific theory'?

If the latter, then can you give some references, to papers published in the relevant peer-reviewed literature, on it?

Well its not a scientific theory. its just a 'speculative idea' that I thought might be possible.

15. Order of Kilopi
Join Date
Mar 2004
Posts
13,441
Originally Posted by Samba
Originally Posted by Nereid
You called this a "theory"; do you mean 'theory' as in 'speculative idea', 'guess'? Or as in 'scientific theory'?

If the latter, then can you give some references, to papers published in the relevant peer-reviewed literature, on it?
Well its not a scientific theory. its just a 'speculative idea' that I thought might be possible.
Thanks for clarity on this point.

Apart from what you have posted in this thread, is there anything freely available - on the internet, say - which describes this speculative idea, how it could be tested, how it relates to well-established theories (of physics), etc?

16. Established Member
Join Date
Dec 2004
Posts
1,005
Negative mass implies repulsive gravity from a point source. Show me an example.

17. Order of Kilopi
Join Date
Sep 2005
Location
Metrowest, Boston
Posts
4,055

## friend in Missouri

Originally Posted by Samba
I think there is negative mass in the universe. Like negative charge. The difference between charges and mass being that Like charges repel but like masses attract. Unlike masses(opposite signs ) repel. Positive mass and negative mass annihilate when they collide, just like charges.

When the Universe was created, Positive and negative mases repelled and got seperated. negative mass in a cluster of Positive mass got annihilated. thats the reason why we dont observe any negative mass around us

What do you think about this theory? Any comment for/against it are welcome.
Samba;974167. I have a friend in Missouri...the "Show me" state. Show me kindly a hardware store or science supply store, or Wal-Mart, Home Depot, or Sears...that carries negative mass in bags or ZipLocs for sale. Then, I'll believe. It also is not showing up in accelerator labs, cosmic ray emulsions, the Fly's Eye in Dugway, Utah, The IMB, Mont Blanc, Kamiokande 2, SNO, DUMAND, AMANDA, or anything else I know of. pete.

18. Originally Posted by trinitree88
Samba;974167. I have a friend in Missouri...the "Show me" state. Show me kindly a hardware store or science supply store, or Wal-Mart, Home Depot, or Sears...that carries negative mass in bags or ZipLocs for sale. Then, I'll believe. It also is not showing up in accelerator labs, cosmic ray emulsions, the Fly's Eye in Dugway, Utah, The IMB, Mont Blanc, Kamiokande 2, SNO, DUMAND, AMANDA, or anything else I know of. pete.

Gravity is a weak force. so our instruments arent sensitive enough to detect the gravitational force of particles. So we cant detect them even if they are there in the labs.

19. Order of Kilopi
Join Date
Sep 2005
Location
Metrowest, Boston
Posts
4,055

## one ,two and a heap...

Originally Posted by Samba
Gravity is a weak force. so our instruments arent sensitive enough to detect the gravitational force of particles. So we cant detect them even if they are there in the labs.
Samba. The Indians used to trade without much of a numerical system...so if trading beaver skins for rifles...one, two and a heap...would do. So it is for gravitational effects of particles. Lacking the exquisite sensitivity for neutron/neutron gravitational forces....we'll do a heap, and let the statistics speak. Statistically the chance of the gravitational wave from SN1987a being coincident as previously discussed elsewhere is >three sigma (Larry Sulak, BU, private communication)...three standard deviations. A macroscopic sample of matter saw something that day, and I'll take 9,999/10,000 odds in my favor at the track any day...I'd bet a house, car, career,hot fudge sundae, or Dunkin Donuts coffee, anytime....and I'll bet that the next type 2 supernova that goes off within 160,000 lightyears will cause another set of coincidences with the same surety. Pete.
P.S. I think I have ~ a year on Alnitak before losing a hot fudge sundae...but it'd be worth it by far. pete.

20. We used to have negative mass as a fictional plot device in OA; by using it n the way suggested by Robert Forward, it made the so-called Diametric Drive possible.
Diametric drive described in wikipedia;
http://en.wikipedia.org/wiki/Breakth...iametric_drive
If one were to construct a block of negative mass, and then attach it to a normal "positive" mass, the negative mass would fall towards the positive as does any mass toward any other. On the other hand, the negative mass would generate "negative gravity", and thus the positive mass (the spaceship itself generally) would fall away from the negative mass. If arranged properly, the distance between the two would not change, while they continued to accelerate forever.
But since evidence for negative mass is not forthcoming, we are slowly eliminating the concept from the site.

Just for fun, here are some pages from round the 'Net which mention negative mass in various ways;
http://www.daviddarling.info/encyclo...tive_mass.html
http://arxiv.org/abs/gr-qc/9705007
http://www.concentric.net/~pvb/negmass.html
http://en.wikipedia.org/wiki/Exotic_...#Negative_mass
http://math.ucr.edu/home/baez/physic...atterFall.html

21. Order of Kilopi
Join Date
Sep 2005
Location
Metrowest, Boston
Posts
4,055

## negative mass supply companies

And...of course....here are all the sources of supply that you can order negative mass from over the internet... pete

They are the same ones that sell all those helium compounds....

22. Hum,
on the street it is commonly referred to as negative mass energy...
Anyone who has come across Hawking radiation will be familiar the proposed virtual photon mechanism...

One of the pair falls into the black hole whilst the other escapes. In order to preserve total energy, the particle which fell into the black hole must have had a negative energy (with respect to an observer far away from the black hole). By this process the black hole loses mass, and to an outside observer it would appear that the black hole has just emitted a particle.
Source

#### Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts
•