The Dark Side of the World
Astronomical observations suggest that the matter we know makes up only a few percent of everything that exists.
By Sebastian J. Szybka
Science reveals that reality has many layers, some of which are not directly accessible to our senses. Physicists, reaching into one of these layers – the quantum world of particles – have discovered that it operates under laws quite different from "our" own. For instance, the properties of quantum objects seem not to be uniquely determined until a measurement is made. It's as if our socks could be both black and red at the same time, with their color only settling, with a certain probability, the moment someone looks at them.
Neutrinos are among the residents of this world. Unimaginably large numbers of these particles pass through our bodies every second, yet it took several decades of developing sophisticated detection techniques to confirm their existence. That was finally achieved in 1956, by observing the behavior of other, already-known particles – protons. In everyday life it's very easy to forget neutrinos exist, because although they're everywhere (huge quantities are produced, for instance, in the Sun), they interact only weakly with the particles that make up everything we're familiar with.
