I’ll say. Thanks for your great explanations. I can’t tell you all enough how much of a treat it is to get answers to some of these questions. 
John Cramer has an enlightening article on negative mass and its peculiar qualities that you might find interesting.
http://www.npl.washington.edu/AV/altvw14.html
A small sample from his article:
If those are the characteristics of “negative matter” (as distinct from antimatter, which has the ordinary material properties regarding mass, inertia and gravitation), then I suppose we would never encounter a very large object, say, asteroid-sized, made of negative matter, because the repulsive antigravitational force would keep it from forming in the first place. Am I right?
It’s worse than that, even. Suppose that there exists a negative-mass particle with a charge. Any two such particles would then accelerate towards each other, eventually forming a macroscopic conglomeration of those particles. Now, consider that an extra gram of electrons each on the Earth and the Moon would be enough to counter the gravitational attraction between the two, and you’ll realize that a macroscopic lump of pure charged particles would have some insane effects.
Cite?
We shouldn’t really need a cite for something we can calculate ourselves.
An electron weighs about 9.1E-28 grams. (using aEb for a*10^b)
So a gram of electrons is about 1.1E27 electrons
Each electron has a charge of 1.6E-19 Coulombs. Thus, a gram of electrons has a charge of about 1.8E8 Coulombs.
Thus, the repulsive force of one gram of electrons acting on another if the two are a meter apart is 9E9 * (1.8E8)^2 = 2.9E26 Newtons. (9E9 is just a constant that appears in Coulombs law, its equal to 1/(4[symbol]pe[/symbol][sub]0[/sub]), where [symbol]e[/symbol][sub]0[/sub] is the permittivity of free space.)
Now of course the Earth and Moon aren’t a meter apart, but since both electric and gravitational forces fall off like 1/r^2, we can set r to 1 meter without changing which one is bigger (and I’m lazy and don’t want to bother looking up the distance between the Earth and the Moon).
The gravitational force of the Earth on the Moon (taking the distance to be 1 meter) is 6.67E-11 (Newtons/kg^2)*mass of Earth * mass of Moon. The mass of the Earth is about 6.0E24 kg and the mass of the moon is about 7.3E22 kg. So the force between the Earth and the Moon (again taking r = 1 meter) is 2.9E37 Newtons.
So, if I haven’t screwed up the math somewhere, an extra gram of electrons won’t do it. Our electric repulsion was a factor of 10^11 too small. It would take about 300 kg on the earth and an equal amount on the moon to do the job. Of course, I’ve treated all the charge as being at the center of the earth and the moon. It would make the repulsion a bit stronger if they were all at the closest point on the surface.
But even if my above calculation is correct, the point that a relatively small macroscopic lump of charged particles can exert incredibly large electric forces (relative to the force of gravity) is still correct.
I’m not following this . . . do you mean that in negative matter, like charges attract like charges? Electrons clump together instead of flying apart? If that were the case – what would hold a negative-matter atom together? The negative protons would have no way of holding the negative electrons in their orbits.
Unlike the extreme reaction of anti matter with matter, a la E=mc^2, reacting mass with anti-mass (negative matter) would simply cross cancel each other.
No explosion, no radiation, NOTHING AT ALL! :eek:
Wouldn’t that like, violate some kind of law of conservation or something?
Well, not conservation of mass, at any rate.
Define “attract”.
Suppose I have two like-charged negative-mass particles, A and B, as such:
A B
Because they have the same charge, A will feel a force to the left, and B will feel a force to the right. So far, this is just like normal matter. But now, we ask, what accelerations would these cause? A is feeling a force to the left, so if we divide by its (negative) mass, we’ll find that it’s accelerating to the right. Likewise, B is accelerating to the left. In other words, like charges will accelerate towards each other (and by the same token, unlike charges would accelerate away from each other). An atom like one of normal matter, with equal numbers of positive and negative charges, would not hold together. The analogous negative-matter object would be two like-charged particles bound together… But this doesn’t cancel the charge, so you could just pile more such charges into the system, ad infinitum.
Nope.
bringing mass and anti-mass together is like saying (+1)+(-1)=0