Oral Communication

Dear fellow students

If you could convert all of the energy contained in 1 kg of sugar, or 1 kg of water, or 1 kg of any other stuff, you could drive a car for about 100,000 years without stopping!

Why? Albert Einstein, in 1905, wrote down the famous equation E=mc2. It says that mass is a very concentrated form of energy.

Energy is like the 'money' of nature; it comes in two different currencies, and with an enormous exchange rate - the square of the speed of light .

kg corresponds to 25,000,000,000 kWh of energy; 1 gr would be enough to supply energy to a medium-sized town for a whole day!

But how can energy be transformed into matter, or vice versa?

We do not have the technology to make a space ship go at the speed of light (300,000 km/sec), but it is possible - using accelerators at CERN - to make single particles (like a proton, the nucleus of a hydrogen atom) go that fast.

If a particle moving with this speed hits a block of material, its energy is also transformed, producing 'temperatures' of 10,000,000,000,000 Co or more. Under these extreme circumstances, the energy set free in the collision will transform into matter.

But: what kind of matter do I produce in such collisions?

In a coin factory, hot metal is pressed into coins. They only come in specific sizes and values, as 1p, 2p, 5p, 10p, 50p and 1 pound.

Similarly, nature does not allow energy to be converted into just any kind of matter. Nature has provided us with 'moulds', corresponding to a precisely defined amount of energy, as well as having some other particular properties.

These moulds are analogous to particles, the most important ones in our daily lives being the proton, the neutron and the electron. They have very precisely defined properties, such as their mass, their electric charge or the way they interact with other particles.

So can I transform energy into a single proton or a single electron?

Imagine a hot metal sheet in a coin factory ('energy'). When you stamp out a coin from a metal sheet, you are left with a coin and a hole in the sheet.You could call this hole an "anticoin".

This is similar to what happens when energy transforms into matter. Many experiments have shown that you can only produce a pair of particle and its mirror image, called 'antiparticle', at the same time. Nobody has ever observed the production of only particles, or only antiparticles.

That example also shows another feature observed with particles and antiparticles. To create them, it takes energy, and when you bring them back together ('annihilation', because they disappear into a flash of energy), this energy is released. It is like putting the coin back into the hole, leaving the original metal sheet.

......................................................................................

It's one of the most attractive words in science fiction literature and nearly as good a topic at parties as black holes. It might also be the fuel that powers spaceships to the planets and perhaps the stars, even if it's just used as a sophisticated book of matches.

Right: Mars in 6 weeks? And back in a total of four months? That's the prediction of a design team working on antimatter rocket concepts at Pennsylvania State University.

"Antimatter has tremendous energy density," said Dr. George Schmidt, chief of propulsion research and technology at NASA/Marshall. Matter-antimatter annihilation - the complete conversion of matter into energy - releases the most energy per unit mass of any known reaction in physics

Anti-protons, explained Dr. Gerald Smith of Pennsylvania State University, can be obtained in modest quantities from high-energy accelerators slamming particles into solid targets. The anti-protons are then collected and held in a magnetic bottle.

....................................................................................................

What do you think of when you hear the word "antimatter?" Something exotic, something unreal

Well, to a few NASA and university researchers, antimatter may just be the future of human space travel. When it comes to packing a punch, antimatter/matter reactions can't be beat. When a particle and its antiparticle meet, they annihilate each other and their entire mass is converted into pure energy.

A Penning trap is tested at Penn State University. Penning traps use a combination of low temperatures and electromagnetic fields to store antimatter. While the traps can only store incredibly small quantities, the traps will help in developing the technologies needed for advanced propulsion concepts. Credit: Laboratory for Energetic Particle Science at Pennsylvania State University.

On Earth all antimatter that exists is counted in individual atoms. Low energy positrons are routinely used in a medical imaging technique called Positron Emission Tomography as well as studies of important materials used in electronics circuits. These positrons are the result of the natural decay of radioactive isotopes. While useful in medical and materials research applications, there are not enough of these anti-electrons to provide a useful form of rocket fuel. High-energy antimatter particles are only produced in relatively large numbers at a few of the world's largest particle accelerators. The current worldwide production rate of antimatter is on the order of 1 to 10 nanograms (billionths of a gram!) per year.

"Antimatter is around us each day, although there isn't very much of it," says Gerald Share of the Naval Research Laboratory. "It is not something that can be found by itself in a jar on a table."

So Share went looking for evidence of some in the Sun, a veritable antimatter factory, leading to new results that provide limited fresh insight into these still-mysterious particles.

Simply put, antimatter is a fundamental particle of regular matter with its electrical charge reversed. The common proton has an antimatter counterpart called the antiproton. It has the same mass but an opposite charge. The electron's counterpart is called a positron.

Antimatter particles are created in ultra high-speed collisions.

One example is when a high-energy proton in a solar flare collides