And I don't see how this relates to the previous examples. In my mind, impact and friction has nothing to do with gravity.
The force between two masses, F is equal to G multiplied m-sub-1 multiplied by m-sub-2, and then all of that divided by the square of the distance between m-sub-1 and m-sub-2. Here G is the gravitational constant and the number being positive indicates a force toward, say, the first partner, m-sub-1.
Now, imagine m-sub-2 is negative mass.
Our force then becomes negative, so a force away from the first partner, m-sub-1.
BUT ...
Acceleration is equal to force divided by mass. Here the mass, m-sub-2 is negative, but so is the force. And so the acceleration is back to being positive and the negative mass "falls toward" the positive mass of m-sub-1.
In other words, positive matter ends up being a "falling toward" field.
Negative matter, however, well, run the numbers, only do everything from the m-sub-2 vantage point. The positive mass, m-sub-1, flees! Even as it attracts the other one.
And so once you have a negative/positive pair, they lock on, one fleeing, one chasing. One ends up with ever increasing positive kinetic energy, the other with ever increasing negative kinetic energy (all starts to sound a little silly here) and they cancel out, from a distance.
Gets wacky once you start imagining this for charged particles, which immediately bunch up into staggering Coulombs of negatively-charged nega-mass particles, and ditto for the positively-charged nega-mass particles. They just rapidly self-sort into these clumps due to the "electrostatic repulsion" going up against negative inertia. The EM force quickly dominates.
These two blazing opposite poles of charge, Q-pos and Q-neg, should naturally attract one another, but for that pesky negative inertia again.
And so all of the negative mass in the universe sorts into Q-pos and Q-neg, then promptly tries to approach the speed of light fleeing from one another, leaving just the slightest of electrical fields evident, but always asymptotically approaching zero as they more or less banish themselves to the further regions of normal matter.
(Some normal matter would be torn along for the ride)
It's a fun thought experiment.
The physics of negative mass/energy are paradoxical to the point that they mathematically enable transluminal transport.
I think so. For most purposes, we can build intuition for special relativity without having to do the math. (General is more fucked.) We don’t understand negative energy/mass enough to even do that.
This is why I want to know if antimatter falls up. Or I guess it might fall down but repel regular matter in which case it'll be very hard to detect.
https://www.riken.jp/en/news_pubs/research_news/pr/2022/2022...
Are there other types of Antimatter that focus on different properties?
We don't know that. It may have the regular charge but after computing the force it may experience the opposite behavior via F=ma since the mass is negative.
We don't really know if the charge is opposite or the mass. Blindly using the equations you may get similar results depending where you stick the negative.
Also, I seem to recall Dirac predicting the existence of antimatter because some solution to an equation had an m^2 term and when you take a square root to solve for m there are two solutions. Then the positron came along and this was forgotten and people just assumed it had positive charge rather than negative mass.
Here is a contrived example calculating a hypothetical quantity X = m * Y.
Suppose we observe that X is always negative.
By your logic, we would then assume that Y is always negative.
This is true if m is never negative, but it is somewhat possible that we would eventually find a situation where m is negative and Y is positive.
Both theory and experimental validation. Their interaction with electric fields, their interaction with gravity, conservation laws, and so on.
In a given interaction, charge is always conserved. So we see interactions where an electron and a positron collide they produce a chargeless photon. So it must have the opposite charge to an electron
Is there energy in an electric field? If so it must be signed or it wouldn't cancel out.
The energy contained in the electromagnetic field is nonnegative: as I understand it, within a given volume, it's simply the sum of the photon energy of all of the photons.
Meanwhile, electrons and positrons exist in their own particle field, and have both positive mass energy and nonnegative kinetic energy. When an electron and positron annihilate and produce photons, they convert their combined mass energy into kinetic energy in the photons. The only thing that gets "canceled out" is the positive and negative electric charge.