Could Matter-Antimatter Reactors Work?

warp speed illustration
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The starship Enterprise, familiar to fans of the Star Trek series, uses an incredible technology called warp drive. This is a sophisticated power source that uses antimatter to produce all the energy the crew needs to warp their way around the galaxy and have adventures. Naturally, such a power plant is the work of science fiction.

But, is it something that could be built someday? Could this concept one day be used to power interstellar spacecraft? It turns out the science is quite sound, but there are definitely some hurdles that stand in the way of making such a dream power source into a usable reality.

What Is Antimatter?

So, what's the source of Enterprise's power? It's a simple reaction predicted by physics. Matter is the "stuff" of stars, planets, and us. It's made up of electrons, protons, and neutrons. Balancing that is antimatter, which is comprised of particles that are, individually, antiparticles of the various building blocks of matter, such as positrons (the antiparticle to the electron) and the antiproton (the antiparticle to the proton). These antiparticles are identical in most ways to their regular matter counterparts, except that they have the opposite charge. If you could bring them together, the result would be a giant release of energy. 

How Is Antimatter Created?

Antiparticles are created in naturally occurring processes of nature, but also through experimental means such as in large particle accelerators on Earth in high-energy collisions. Recent work has found that antimatter is also created naturally above storm clouds, providing the first means by which it is produced naturally on Earth. 

Otherwise, it takes massive amounts of heat and energy to create antimatter, such as during supernovae or inside main-sequence stars (such as the Sun).

How Antimatter Power Plants Could Work

In theory, the design is quite simple, matter and its antimatter equivalent are brought together and immediately, as the name suggests annihilate each other.

The antimatter would be contained separate from the normal matter by magnetic fields so that no unintended reactions take place. The energy would then be extracted in much the same way that nuclear reactors capture the expended heat and light energy from fission reactions.

Matter-antimatter reactors would be orders of magnitude more efficient at producing energy over the next best reaction mechanism (fusion). It still is not possible to fully capture the released energy. A significant amount of the output is carried away by neutrinos which are nearly massless particles that interact so weakly with matter that they are nearly impossible to capture (at least for the purposes of extracting energy).

Problems With Antimatter Technology

The primary difficulty with such devices is obtaining a significant amount of antimatter to sustain a reactor. While we have successfully created small amounts of antimatter, ranging from positrons, antiprotons, anti-hydrogen atoms and even a few anti-helium atoms, they haven't been in significant enough amounts to power much of anything.

If you were to gather all of the antimatter that has ever been artificially created it would scarcely be enough to (when combined with normal matter) light a standard light bulb for more than a few minutes.

Furthermore, the cost is high. Particle accelerators cost too much to run at very high energy even to produce a small amount of antimatter in their collisions. In the best-case scenario, it would cost on the order of $25 billion to produce one gram of positrons. Researchers at CERN point out that it would take 100 quadrillion dollars and 100 billion years of running their accelerator to produce a single gram of antimatter. 

Clearly, at least with technology currently available today, the regular manufacture of antimatter does not look promising. However, NASA is looking for ways to capture naturally created antimatter, and this could be a promising way to power spaceships as they travel through the galaxy.  Where would they look for a collection of antimatter?

Searching Out Anti-matter

The Van Allen radiation belts (doughnut-shaped regions of charged particles that surround the Earth) contain significant amounts of antimatter created as very-high-energy charged particles from the Sun interact with Earth's magnetic field. So it may be possible to capture this antimatter and preserve it in magnetic fields "bottles" until a ship could use it for propulsion.

Also, with the recent discovery of antimatter creation above storm clouds it could be possible to capture some of these particles for our uses. However, because the reactions occur in our atmosphere, the antimatter will inevitably interact with normal matter and annihilate; likely before we have a chance to capture it.

So, while it would still be quite expensive and the techniques for capture are still under study, it may be possible someday to develop a technology that could collect antimatter from the space around us at a cost less than artificial creation on Earth.

The Future of Antimatter Reactors

As technology advances and we begin to understand better how antimatter is created, scientists can begin to develop ways of capturing the elusive particles that are naturally created. So, it's not entirely impossible that we could one day have energy sources like those depicted in science fiction.

Edited and updated by Carolyn Collins Petersen.