IS ANTIMATTER POTENTIALLY OUR NEXT ENERGY SOURCE?

The answer to the question in headline is: NO. What you’ll read next is the reason why not.

Basically it’s quite simple to grasp why this is out of reach. First of all is because we don’t know much about it, and second  we simply don’t quite understand how antimatter behaves really nor we could ever deal with it consideralbly better.

ANTIMATTER AS SOUCE OF ENERGY

To understand how antimatter works is important to review a little how matter works. As you know everything in our world is made of matter, namely from tiny units we call atoms. There 118 different types of atoms currently known to us and we have classified them in a chart known as The Periodic Table. Matter is the stuff that makes up stuff around us. And the description of this stuff of matter belongs to a branch of science called particle physics. This tells us that the Universe is actually very simple, that all the matter, all the stuff that you see around you is made of just a few fundamental ingredients or fundamental particles as we call them, 12 of them actually: 6 quarks and 6 leptons.

And just to set the scale of the very smallest of detail that the particle physicists worry about, these fundamental particles are at least as small compared to atoms, as atoms are compared to you. And I say “at least” because they’re so small, that we haven’t actually been able to measure their size. They’re like pin pricks. Now, at least when you get down to these very, very tiny distances the Universe is simple. In fact is slightly more complicated than this because this is just matter and we also know that antimatter exists.

For us as macro entities, it’s obvious that we can explain and understand much better what’s going on in our macro world. We understand matter better because it occurs in both micro and macro environment, so we can make correct analogies to explain what we see. Yet Antimatter, as little as we know about it, belongs to micro world. We only know about it for a century and its existence was proven by intense experimental observation and mathematics. The existence of a bulk of antimatter was never observed in our Solar System and neither beyond it in the visible universe to us (in a radius of around 46 billion light-years away from Earth). Hence, as long as we don’t have evidence of antimatter at macro level we cannot know precisely how antimatter behaves. The best we can do is to keep experimenting and conclude with the most plausible theories and hypothesis.

Matter on the other hand, also has its own characteristics at microscale, but as we have it at macroscale we can deal with it much easier.I give you a simple example about how precisely we know what matter does at microscale and the outcome of this, is what we actually experience at macroscale.Let’s consider plants. I have them in my room too.

As I watch my plants grow I don’t see the carbon and oxygen atoms pulled from the air and transformed into the leaves; my breakfast cereal mysteriously turns into me, and yours into you because it is the molecules being rearranged; it is the atoms calling the tune and we lumbering macro-beings see only the large end products. As the atoms do their work, energy is liberated. The food that you ate some hours ago is turning into you, and into waste, but also producing the energy for life and keeping your body warm. Body temperature is the result of chemical reactions; it is Einstein’s E = mc² at work.

A small amount of the mass (the m) in your food is lost as the food is transformed and turned into energy (the E) at an exchange rate that is the square of the speed of light (c²). In percentage terms the difference in weight between the food added to you minus any that you subsequently excrete is so small, about one part in a billion or a microgram in a kilogram, that to measure it with accuracy would require you to account for the traces of sweat and assorted DNA that every action transfers to everything we touch. It would be a hopeless task. The conversion of one part in a billion of mass into energy is at the root of chemistry, biology, and life. It is also the source of the power of gunpowder and chemical explosives. These processes involve the electrons in the outer reaches of the atoms. However, vastly greater amounts of energy are accessible in the atomic nucleus. Atom for atom, the amount of energy released from the nucleus is up to 10 million times greater than from its electrons. So whereas chemical reactions convert just one part in a billion of matter’s trapped energy, nuclear reactions can liberate up to about 1%.

Each of these fundamental particles of matter has an antimatter equivalent. So we have anti-quarks as equivalent of quarks, anti-leptons as equivalent of leptons, the antimatter version of a negatively charged electron, it’s the positively charged anti-electron (a.k.a. positron). The antimatter equivalent of the positively charged proton that contains quarks, then that gives me the negatively charged anti-proton that contain anti-quarks. Antiparticles (such as positrons and antiprotons) can bind with each other to form antimatter (such as antihydrogen), just as ordinary particles bind to form normal matter. With other words, Antimatter and Matter are really similar. They don’t differ by very much.

The power of chemicals comes about because although each individual atom releases only trifling amounts, there are up to 10²⁴ of them in each gram, each of which can contribute. If we could transform larger fractions of matter into energy, our ambitions would expand in parallel. In principle we could liberate the full mc² latent within matter into energy. That is the promise of antimatter. When you have antimatter meeting matter it annihilates, releasing enormous amounts of energy. If I have a quarter of 1g of normal matter meeting a quarter of 1g of antimatter then the resulting annihilation has the explosive force of 5kT of TNT.

Nuclear processes likewise use large amounts of uranium ore that can be dug from the ground and processed; nature locked in the energy aeons ago, and now we can liberate the 1% from trillions and trillions of atoms. So you might think that particle physicists have perhaps discovered the next source of fuel. Like that we might have solved the world’s energy crisis and been keeping it very quiet because we’re hoping to make a lot of profit. If only that would be true. And what stops this being true is the fact that for antimatter there is no such possibility As far as we know all of it was destroyed 14 billion years ago.

If you want to use antimatter you must first make every antiparticle, which is a very inefficient process. This is a fundamental restriction in nature: although the total energy is conserved in any production process, the amount of useful energy decreases due to friction and general waste. Consequently, because of these losses, only a trifle of the energy used ends up in antimatter particles, the result being that it costs much more energy to make them than can be recovered during their subsequent annihilation.

Antimatter is in fact the most expensive substance known to mankind. Unlike matter, antimatter is not common. Unless you’re in the upper atmosphere, or inside a particle accelerator, you’re not going to stumble across it. It is not found in nature and can only be prepared in a lab. For the past few years, scientists at CERN (European Organization for Nuclear Research) have been synthesizing antihydrogen by slowing down high-energy antiprotons and smashing them into positrons. But since antimatter is explosive (it blasts when it comes in contact with normal matter) and energy-intensive production, the cost of making antimatter is astronomical. The antihydrogen made in CERN’s laboratory only amounted about a mass of about 1.67 nanograms. To make a gram of the antiproton, scientists will have to continue production at the current rate for another 6X10⁸ years and the total cost would be an astronomical 2.58×10¹⁵€.

It’s so expensive because it’s so rare, it’s so difficult to produce. That’s not to say it doesn’t exist altogether, we get antimatter in the Universe, because things decay radioactively. So in fact bananas are a good source of antimatter. A banana every day will release 15 anti-electrons, believe it or not. But 15 is such a small number compared to the vast number of particles that make up a banana that for all intends and purposes, we just really almost don’t have any antimatter in the Universe at all. It’s ridiculously rare.

ANTIMATTER IN GENERAL

Suppose we want few grams of antimatter. Whether the plan is to bomb the Vatican as in Dan Brown’s novel “Angels and Demons” or to make fuel for Star Trek, or for a power source, all of them beg the question not just of how to make and store it, but what it should consist of. There is no need for special combustible chemistry like anti-TNT or benzene; it is the annihilation that releases energy so the simplest possible antimatter will do. We have to make it one antiparticle and anti-atom at a time. The question then is how best to assemble the stuff for storage. This is where the reality of nature rather than the fancies of science fiction begin to spoil the dream. To make 1 gram of antiprotons requires nearly a trillion trillion of them; to do it with positrons requires 2000 times more. The numbers are huge.

To give an idea of what this means, since the discovery of the antiproton in 1955, with LEAR (Low Energy Antiproton Ring) at CERN in Switzerland and similar technology at Fermilab in the USA, the total amounts to less than a millionth of a gram. If we could collect together all that antimatter and then annihilate it with matter, we would only have enough energy to light a single electric light bulb for a few minutes. By contrast the energy expended in making it could have illuminated Times Square Piccadilly Circus. Of course those facilities were designed to make beams of antiparticles for specific experiments, not for storage in large quantities. Nonetheless even were we to design a machine specifically with the aim of building bulk antimatter, it is still a long way from tens of millions of years to a production line with a timescale of weeks. And when all that is done, you would still need to store it.

To store antimatter, first, you need a high vacuum and a container comprised of electric and magnetic fields. Then second you must know how to do that, namely to successfully store antiparticles in electric and magnetic fields. One piece of good news is that we know how to do that and have successfully stored antiparticles in Penning traps for many weeks. However, there is a limit to how many you can keep in the “bottle” as problems arise when lots of charged particles are gathered in a small volume. The unavoidable fact of nature is that electrically charged particles with the same sign of charge mutually repel, so the more you have, the harder it becomes to squeeze them inside the magnetic bottle. About a million antiprotons is the largest number successfully stored, and before you get excited, that is a billion billion times smaller than what you would need for a gram. A leaky bottle of antiparticles is not the answer of how to contain the ultimate destroyer.

One way to avoid this problem is to have a mixture of positrons and antiprotons, as atoms of antihydrogen. The electric charges of the positive positrons and negative antiprotons cancel one another, so the problem of too much electric charge need not worry us. We ourselves are made of billions of atoms, which contain balanced positive and negative charges such that overall we are unaware of the electrical activity within. The same could apply to antimatter. But do you see the catch?

The magnetic ropes and electric walls that make the prison only confine electrically charged “prisoners”. If those “prisoners” have paired off so that their individual charges cancel to nothing, the power of the prison walls disappears like magic; to contain anything in an electromagnetic bottle needs some residual forces between the bottle and the thing. Atoms of antihydrogen are neutral to the electric and magnetic fields, and soon float off freely until, uncontained, they escape, meet matter, and are prematurely destroyed. There are examples of bulk matter where the effects of the inner electrical charges can still be felt. The most familiar is magnetism, where the motion of electric charges gives magnetic effects; although the total negative and positive charges may annul one another, the net motion of the electrons may be like an army on the march, acting in step, so that their individual little pieces of magnetism add up. The same would happen for antimatter; as iron in our material world can be magnetic, so could anti-iron be magnetic in the anti-world. However, as the collection of lots of like-charged particles competes with the electric forces in the bottle, so would a magnetic collection interfere with the magnetic fields. It might be possible to trap some antihydrogen atoms in magnetic fields that change rapidly throughout the volume, so that the different magnetic moments of the positron and antiproton will hold the atom, but this has not been achieved even for a few anti-atoms.

Another possibility is to make atoms of positronium – a positron and an electron. This has attracted the interest of the US military in recent years. Problems here are not just the fact that this atom is electrically neutral, like antihydrogen, but also that its constituents mutually destroy one another. The lifetime of a positronium atom is less than a thousandth of a second, far too short to use them as an energy storage device for a voyage to Mars. Nonetheless, the US Air Force believes in this enough to be pouring money into research. I am just wondering: What can they be up to with this?