Anti-matter

[Shrykull]

How do they make anti-matter, and how far are we from using M/AM as a power source?

[Beowulf]

Smash one atom into another atom, and out comes a bit of anti-matter...

I think we currently make on the order of picogram a year, so I would say quite far from using M/AM as a power source, especially considering that most of the radiation from the reaction is not useable to turn into energy.

[GrandMasterTerwynn]

How do they make anti-matter, and how far are we from using M/AM as a power source?

Yep, currently the only way we have of making antimatter is to smash really heavy atomic nuclei into other really heavy atomic nuclei. This creates a few antiparticles in the ensuing zoo of crap. Unfortunately, this generates very, very, very tiny amounts of the stuff, and we have very, very, very tiny quantities of antimatter stored.

Before we could use M/AM power sources we'd have to solve the following problem:

Production volume - We need to find more efficient and cheaper ways of producing antimatter. And when I say cheaper and more efficient, I mean by many orders of magnitude.

So, we're likely at least one or two centuries away from M/AM power.

[Sea Skimmer]

How do they make anti-matter, and how far are we from using M/AM as a power source?

Matter/anti matter is a net loss energy source. You use significantly more power to make anti matter then you can collect from annihilating it.

As a result it is highly unlikely to ever be used on Earth. Only in space where fuel supply's mass and bulk become an issue is it likely to see use. And even there I'd say sufficiently more then 100 years before it sees use.