Anti gravity??

[hawksmere]

I have just read Fank Close's Antimatter book and he mentiones anti-gravity several times. It doesn't however explain if antimatter or antiparticles adhere to positive gravity. Sorry if this makes little sense. Also do quark charges simply reverse in anti-particles? ^^v to vv^?

[Schrödinger's hat]

I have just read Fank Close's Antimatter book and he mentiones anti-gravity several times. It doesn't however explain if antimatter or antiparticles adhere to positive gravity. Sorry if this makes little sense. Also do quark charges simply reverse in anti-particles? ^^v to vv^?

 

I don't think anyone has ever isolated antimatter for long enough to check, but the prevailing theory is that it would fall the same direction as matter.

The electromagnetic charges are opposite for all anti-particles.

If you were talking about other charges, I'm not so sure. Color charge works in its own way (the anti-color charges act a bit like secondary colors, where color charges work analogously to primaries). No clue about parity, and I don't know what reversing the spin of a particle would entail as you can measure it as both positive and negative of its values for the normal matter particles.

[hawksmere]

Thanks for your answer. I too don't understand it. However Feynman's eponymous diagrams can surely be 'reversed'. So in essance when watching positrons are we not actually watching electrons from the future? Or if we reversed the action then we will not be able to tell which was the future or the past, they will be intertwined. If the signs of electrical charges ae reversed we would not know what time it is which is the symmetrry between matter and anti-matter (electrons and psitrons).

 

Charge, Parity and time must all be reversed, which are being reversed in all anti-particles so the arrow of time is revesed. Or is it?

[Enthalpy]

A few arguments against antiparticles repelled by gravity:

 

- Their inertial mass is absolutely normal. Shall their gravitation mass differ from the inertial one this time?

- Intense gravitation fields, like the horizon of black holes, would create pairs and eject streams of antiparticles and swallow the particles.

- When a pair is created from energy, some mass+energy would disappear. And why would the gamma ray need a minimum energy to create a pair?

 

Experiments do isolate antimatter for some time! Antihydrogen has been produced and stored for long enough to measure its optical spectrum. Maybe weight could be observed in these experiments.

 

Thanks to have cited the source of this strange idea...

[hawksmere]

Enthalpy thanks for this. But not enough time to create a weapon (anti-matter weapon like the one in Dan Brown's Angel and demons). They used an anti-hydrogen in the film and were apparently publicizing what the US AIR FORCE have been accused of funding.

 

"Positron energy conservation will be used for anti-matter annihilation energy, which will provide aircraft with propulsion and offensive capabilities. Eglin air force base requires the following performance specifications for the prototype." VAGUE!!!

 

I understand the reason being storage issues and costs but it would impossible to create radioactive and pollution free anti-matter weapons, surely ( at the least gamma rays!). Considering a single gram of anti-matter contains the energy of a 20 kiloton nuclear bomb! Also, storing it according to ALPHA has many issues and is ridiculously expensive! so it will not only take millions of years to create extract even a gram of anti-matter it will also cost a 'bomb'!