xtraordinaryevidence wrote:Isn't anti-matter essentially the same as matter but with opposite charge (and/or spin?)? Different types of ordinary matter have different charges but are affected by gravity, so they are right in that it would shock the physics world.

This was my thinking. Gravity would have to be affected by the charge of the particle for an anti-gravity to exist.

RationalVegan wrote:

CdesignProponentsist wrote:My guess is that anti-matter has normal gravity. Wouldn't a particle that exerts anti-gravity require negative mass?

Is negative mass possible? Would that not be the same as having negative size and is negative size not impossible?

Its theoretical exotic matter that would be comprised of negative energy as regular mass is comprised of positive energy.

It is mentioned at the bottom of that page that in fact if anti-matter does have anti-gravitational influence, then it would probably be an indication that negative mass is possible and real in the form of anti-matter.

I guess my gut was right in my original question.

mraltair wrote:

xtraordinaryevidence wrote:Isn't anti-matter essentially the same as matter but with opposite charge (and/or spin?)? Different types of ordinary matter have different charges but are affected by gravity, so they are right in that it would shock the physics world.

This was my thinking. Gravity would have to be affected by the charge of the particle for an anti-gravity to exist.

It would be effected by the energy state, not charge. Negative energy would produce anti-gravitational effects.

What they are trying to determine is whether anti-matter also has negative mass as well as reversed charge.

imaginary/quaternion masses, praps?

Some discussion and references here.

New stuff here:

http://www.bbc.co.uk/news/science-environment-17200308