It turns out that everything in the universe exists in two different ways. Or, at least in two different ways in which we attempt to conceptualize things. It all started with light. Normally, we think of light as a wave. However, it’s been shown that light is also a particle (known as a photon). The fact is that depending how you choose to observe it, light can behave as either a particle or a wave (though never both at the same time). Then, the physicist Louis de Broglie put forth the idea that all matter actually has this wavelike nature, a theory which was shortly after demonstrated by experiments on electrons. To put it simply, everything is a particle, and everything is a wave. We don’t see this effect in macroscopic objects because the larger the object, the smaller the wave…so in a big object its wavelength is unnoticeably tiny. But it’s certainly an observable phenomenon in the subatomic realm. Whether you observe a particle or a wave simply depends on what type of observation you are making.

The fact that something can be both a particle and a wave seems like quite a paradox. If you’re having trouble conceptualizing this idea, you’re not alone. It’s caused a lot of philosophical consternation among physicists for many years.

(From the Physics series...entire series can be browsed here: [link] )