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# Nice paper: Constraints on possible "antigravity" of antimatter

A new preprint on arXiv does an excellent job of deriving strong constraints on the possible "antigravity" (gravitational repulsion) of antimatter, based on very precise experimental data and a minimum of theoretical assumptions. Karshenboim goes through several complex and detailed analyses to set tight limits on antigravity effects.

The argument I like best goes as follows: if antimatter feels a gravitational repulsion relative to matter, then "pure neutral" bodies, like positronium (bound states of e+ and e-) or photons (which are their own antiparticles) should feel no gravity at all. That trivially contradicts the gravitational deflection of light, and therefore can't be true.

## Discussions

If only i understood phisics more... i guess i'll have to wait till next year, when i'll have the class

It's not unreasonable until you take the course -- does your school have good science teachers? You could also do some reading up on your own; a lot of the physics I've been mentioning in I'bles doesn't need any maths beyond algebra (my own research work does, of course :-). There are many good introductions to physics, both classical and modern (quantum and relativity), aimed at people with high-school level maths. Ask your teachers, or just look around on Amazon.

I don't really know about teachers..

I can't learn straight from the book, i have to have a teacher explain it in class, only then i can do it (any subject but English, PE, or electronics)

There is a government lab in town, LLNL i don't really know if that counts for anything, i think it might

You're in Livermore? You've got some outstanding resources, both through the lab and through the schools there. Ask around! If you're interested in physics, many of the labs (LLNL, LBNL in Berkeley, SLAC) and Universities have summer internship programs for high school students. We (SLAC, a bit of a haul for you) have public lectures weekly on various science topics. I do understand your issue with needing interaction with an instructor for effective learning.

That's just the way i learn, i have to see each step separately