Does Negative Mass Exist in the Universe?

[Haelfix]

Guys this isn't very complicated.. Eqns of motion of a negative mass particle (-m)

F = (-m) a = G (-m) m /r^2 ==> a = GM/r^2. It accelerates towards a positive mass particle, just as normal mass does.

Whats the difference?

the positive mass charge

F = ma = g m (-m) /r^2 ==> a = -gm/r^2. The positive charge runs away.

So the situation is highly asymetric, the negative mass charge chases the positive mass charge. Gauss's law no longer holds, and the system is unstable, no equilibrium can ever be reached. That is why, in a nutshell, the situation cannot exist in a world of both positive and negative mass.

 

[Rade]

Guys this isn't very complicated.. Eqns of motion of a negative mass particle (-m)F = (-m) a = G (-m) m /r^2 ==> a = GM/r^2. It accelerates towards a positive mass particle, just as normal mass does.Whats the difference?the positive mass chargeF = ma = g m (-m) /r^2 ==> a = -gm/r^2. The positive charge runs away.So the situation is highly asymetric, the negative mass charge chases the positive mass charge. Gauss's law no longer holds, and the system is unstable, no equilibrium can ever be reached. That is why, in a nutshell, the situation cannot exist in a world of both positive and negative mass.

But, is this not only the case when the positive and negative masses are identical ? -- more interesting, IMO, is when masses are not identical--in that case the two should meet, but whether or not they form stable union is unclear--is this not correct ?

 

[Haelfix]

You can conspire them to get close (to at least epsilon) if you want, just tune the initial conditions. A mass difference would affect the eqns of motion as well, same difference.

The situation would not be stable classically though, as I mentioned. I don't know what the quantum behaviour would look like, short of doing the calculation, but I'd venture to guess it would be a mess, likely with states violating SR and so forth, tachyons all over the place etc.

 

[rbj]

Guys this isn't very complicated.. Eqns of motion of a negative mass particle (-m)

F = (-m) a = G (-m) m /r^2 ==> a = GM/r^2. It accelerates towards a positive mass particle, just as normal mass does.

Whats the difference?

the positive mass charge

F = ma = g m (-m) /r^2 ==> a = -gm/r^2. The positive charge runs away.

So the situation is highly asymetric, the negative mass charge chases the positive mass charge. Gauss's law no longer holds, and the system is unstable, no equilibrium can ever be reached. That is why, in a nutshell, the situation cannot exist in a world of both positive and negative mass.

i've been trying to tell them that a zillion times in the other thread (in the Classical Physics forum) with a similar, but not exactly the same title. I'm not sure why they don't get it. it's like they allow the EP to hold for some cases, but then insist on an absolute value function to convert inertial mass to graviational mass in some other context.

in the nutshell, the reality of negative mass (in our universe) is akin to the reality of a perpetual motion machine and the obsolecense of the conservation of energy and the end of any energy crisis that humans may experience.

 

[Rade]

Any thoughts on the use of (+ -) in the equation number (5) [F(r) = +-Gm1m2/r^2] in this paper on negative mass ?:http://arxiv.org/PS_cache/physics/pdf/0308/0308038.pdf

 

[Andrew Mason]

i've been trying to tell them that a zillion times in the other thread (in the Classical Physics forum) with a similar, but not exactly the same title. I'm not sure why they don't get it. it's like they allow the EP to hold for some cases, but then insist on an absolute value function to convert inertial mass to graviational mass in some other context.

in the nutshell, the reality of negative mass (in our universe) is akin to the reality of a perpetual motion machine and the obsolecense of the conservation of energy and the end of any energy crisis that humans may experience.

Your concerns about energy are certainly well taken but I am not sure that it leads to a violation of conservation of energy since negative mass would have negative energy. What that means in the real world is not clear to me at this point.

Just a thought: The idea that normal matter can be pushed outward forever by negative matter is interesting. Perhaps it is negative mass that is causing the universe to expand at an ever increasing rate!

AM

 

[rbj]

Any thoughts on the use of (+ -) in the equation number (5) [F(r) = +-Gm1m2/r^2] in this paper on negative mass ?:http://arxiv.org/PS_cache/physics/pdf/0308/0308038.pdf

well, i disagree with adding \pm to it and that matter and "antimatter" (i would use the term "negative mass") both repel each other. positive mass attracts the negative mass (as it attracts any mass), but negative mass repels the positive mass (as it repels any mass).

but i got to read the rest of the paper.

 

[rbj]

Your concerns about energy are certainly well taken but I am not sure that it leads to a violation of conservation of energy since negative mass would have negative energy. What that means in the real world is not clear to me at this point.

Just a thought: The idea that normal matter can be pushed outward forever by negative matter is interesting. Perhaps it is negative mass that is causing the universe to expand at an ever increasing rate!

that's what that arxiv paper that was just brought to our attention is about.

my belief that two equal sized balls of mass, but one of them positive and the other negative, will together accelerate indefinitely is what i think leads to a violation of conservation of energy (what that paper calls the "negative-mass paradox"), but so does the accelerating expanding universe except if there is that "dark energy" that's stored up somewhere that's doing it.

i don't think anti-particles are supposed to be negative mass. they have positive mass (and opposite charge) of their normal counterparts and when a particle and anti-particle annihilate each other, the two positive masses are converted to a net positive energy. ain't that the way it's supposed to go?

 

[advitiyas]

IS anTI-MATTER SIMILAR TO NEGATIVE MASS, WHAT ABT BLACK MATTER.

 

[ambresh]

the existence of an antiparticle is a reality eg positron the antiparticle of electron. So far we don't have any experimental evidence for the existense of -ve mass but the property that like masses would attract and opposite would repel is similar to the fact that two wires with the current in the same direction attract and repel each other if the direction of current in them is in the opposite direction. I have heard that masses can be represented in terms of charges (probably in string theory) may be from there we may conclude something.

 

[arivero]

Guys this isn't very complicated.. Eqns of motion of a negative mass particle (-m)

F = (-m) a = G (-m) m /r^2 ==> a = GM/r^2. It accelerates towards a positive mass particle, just as normal mass does.

What about a negative length too?


it would change the sign of the aceleration. you can postulate that negative mass sees negative leghts and save the day

 

[Severian]

I am afraid I don't have the stamina to read the whole thread, but I thought I would make a comment anyway.

In Quantum Field Theories negative mass doesn't make much difference. For a scalar (spinless) object, the expression in the Lagrangian (ie. the physical description) is alway m^2, so if m<0 you get the same thing. Therefore whether or not the mass is positive or negative is just a matter of definition.

For a fermion, the mass in the Lagrangian is linear but you can just redefine your fermion field to make it positive.

As for GR, the important quantity is the energy, not the mass, so the appropriate question would be, 'are there negative energy states?'

In other words, I don't think there is any reason why you couldn't have negative mass, but it would behave exactly the same as what we already see, and would just be a definition. A more interesting question is 'are there imaginary masses'?

 

[Rade]

...A more interesting question is 'are there imaginary masses'?

By imaginary do you mean masses that mathematically can only be described by (i) as a type of complex number superposition between real + imaginary, where i = the square root of -1 ?

 

[Severian]

By imaginary do you mean masses that mathematically can only be described by (i) as a type of complex number superposition between real + imaginary, where i = the square root of -1 ?

Yes, so that the square of the mass is negative, and the particle is a tachyon.

 

[Norman]

Yes, so that the square of the mass is negative, and the particle is a tachyon.

Not really all that interesting since it has been rigorously proven that you cannot send a "message" with a tachyon. Check out john baez's site for a great explanation of it.

 

[selfAdjoint]

Not really all that interesting since it has been rigorously proven that you cannot send a "message" with a tachyon. Check out john baez's site for a great explanation of it.

WIth all respect to Professor Baez, the history of "rigorous no-go theorems" in physics is not too magnificent.

 

[Norman]

WIth all respect to Professor Baez, the history of "rigorous no-go theorems" in physics is not too magnificent.

A very good point that made me smile a little also at how cavalier my statement was. But the experimental search for the tachyon has not been too magnificent either... so I suppose we will wait.

 

[Severian]

Not really all that interesting since it has been rigorously proven that you cannot send a "message" with a tachyon. Check out john baez's site for a great explanation of it.

It is interesting because of the consequences the presence of a tachyon would have for the stability of the vacuum.

 

[actionintegral]

Do not loose track of reality. According to David Gross (Nobel Luareate) We are in a state of confussion...these equations tell us nothing about where space and time come from and describe nothing we would recognize. We are missing something fundamental.
What we know is a collection of mathematical short cuts which predict. we know not why or how.

I came across this post out-of-context. I would like to know more about it.

 

[Nexus555]

Here's something interesting to think about. If negative mass did exist, it would probably be nearly impossible to identify in the lab. Think about it, negative mass means negative gravity, which means something with negative mass wouldn't attract matter, it would repel it... To me that means that we won't be able to find it anytime soon, because it's repel away from positive gravity...

I'm very doubtful and unsure about dark energy/matter at this point, but a good idea would be that the dark energy and matter is actually the negative mass/energy in the universe, and it may cause the universe to expand because it's reactions with positive mass and energy. Maybe that's why it "spreads" too, because when it comes on contact with new space, it attracts the NEGATIVE mass and energy and continues to repel positive mass and energy...

Just an assumption.

 

[Haelfix]

"In other words, I don't think there is any reason why you couldn't have negative mass, but it would behave exactly the same as what we already see, and would just be a definition. A more interesting question is 'are there imaginary masses'?"

It wouldn't make much of a difference for electroweak or strong force interactions, but it very much would for gravity. Since the equations of motion for a massless spin2 gauge field just reduces to Newtons law in the nonrelativistic limit...

 

[Hans de Vries]

"In other words, I don't think there is any reason why you couldn't have negative mass, but it would behave exactly the same as what we already see, and would just be a definition. A more interesting question is 'are there imaginary masses'?"

It wouldn't make much of a difference for electroweak or strong force interactions, but it very much would for gravity. Since the equations of motion for a massless spin2 gauge field just reduces to Newtons law in the nonrelativistic limit...

Imaginary masses would flip the sign in Klein Gordon:

\partial^2_t \psi - \partial^2_x \psi \ =\ m^2 \psi

Which says as much as: "The acceleration of psi away from zero is
proportional to psi..." This gives us the Bessel I1 and K1 functions
in the space-time propagator instead of the usual J1 and Y1 from
which the Bessel I1 nicely shows the explosive result...

http://mathworld.wolfram.com/ModifiedBesselFunctionoftheFirstKind.html
http://mathworld.wolfram.com/ModifiedBesselFunctionoftheSecondKind.html

(Unless you have a λ which holds it back at 4th order of course.)

The Bessel K1 is not so explosive but it still haunts us today as the thing
which is supposed to cause propagation outside the light-cone over a
range of 1/m, like in P&S (2.52) and Zee (I.23). This "leaking range"
would be infinite in the limit case of massless particles. Simulations
however don't show any propagation outside the light-cone at all.

This story goes back to RF's "Theory of positrons, 1949" where he
found the Hankel functions in the tables instead of the separate Bessel J
and Bessel Y functions. The Hankels are the complex combinations
I1 + i Y1 and I1 - i Y1 and the Y1 becomes our K1 outside the
light-cone where the argument becomes imaginary...Regards, Hans

 

[petm1]

does negative mass exists?

I would think that negative mass as it relates to us, would be the wake of our movement through existence, we are always at the flux point between where we are and where we have been and negative mass being that part of space where mass was, after it has moved on. I would think that photons show us negative matter at all times, and the only time you sense positive mass is when you touch it.