Particles of Life - Part 2

This past weekend, at least for up here in Canada, it was thanksgiving. University kids all went home, who could at least, and were able to see family and friends they've been away from for the past few weeks and gave thanks for the life around them. That life, as we discussed in the last post, is made up of particles. Particles are everywhere, in all kinds of different forms of matter and energy. So far we've talked about some of the basic ones of matter. Now we will talk about some of those of energy.

The particle energy which we appear to interact with most would be the photon, which is the particle that makes up light or electromagnetic radiation. This is everything from x rays when you go to the doctors office to the microwaves that heat your food, to the gamma rays coming out of exploding stars. Light is everywhere. A photon is theoretically one unit, or division of light; one single particle. The different types of light, only one of which is the different light we see every day, come from the different energies contained in the individual photons. For example gamma rays are a type of electromagnetic radiation which contain a large amount of energy, and as a result we cannot see them. The interesting thing about light and electromagnetic radiation is it is not only represented as a photon or a particle, it is also represented as a wave, but this is something for another day.

Another intriguing particle of energy is the neutrino. Neutrinos are very tiny, weakly interacting but very abundant particles which are the result of some nuclear decay and interactions. They can also come from interactions in stars and other cosmic activity, so neutrinos are coming from everywhere in the sky. When I say weakly interacting, I mean very weakly. They have no electric charge so they are not effected by any electromagnetic forces, and they have a very very small mass so the influence of gravity is very small. They interact so weakly, they can pass through most matter totally unimpeded. There are trillions of neutrinos passing right through the earth, and even through your own body, with no affect at all.

This makes detecting neutrinos quite the problem. One way to do this is by using heavy water, or something called deuterium oxide. When the cosmic neutrinos pass through the heavy water, they can actually interact with the molecules and release a certain type of radiation that can be identified as coming from a neutrino interaction. This field of study is relatively new, but as scientist refine the methods of detection, we will be able to learn more about what neutrinos are.

These are 2 of the more common types of energy particles you will hear about in physics, but there are of course many more. There is another grouping of particles we have yet to discuss, and those are particles of force. We will discuss these in the next post.