Let's light things up!

For many of you, light is just this curious entity that enables us to see things in our real life. In fact, what we call light - the visible light - is only a tiny fraction of what it really is. Light is a so-called electromagnetic wave, that combines both an electric and a magnetic field within it. If you are familiar with waves, you know that each wave has some characteristics, its wave length and its frequency. For electromagnetic waves these quantities are connected via a simple mathematical relation:

c = λ f,
where c its the speed of light (the absolute limit of speed in the universe - let's say that nature is a really strict traffic policeman that strictly denies movements over this speed), λ is the wavelength and  f the frequency of the wave.

Light is essential for our lives on Earth. Sun emits sunlight which provides the energy that green plants use to create sugars mostly in the form of starches, which release energy into the living things that digest them. The sunlight that is so beneficial for our lives comes from nuclear reactions - fusion inside the core of the Sun, where Hydrogen atoms fuse into Helium.

[SPOILER] More about the lives of he stars next week!

The curious nature of light is that it behaves both as a wave and as a particle. Quantum Mechanics shows us that light can be described by the existence of light particles, called photons - from the greek word φως - while light can also be described in some cased by the laws of optics. This wave-particle duality is a mystery in modern Physics.

Today we post about light because 2015 is the International Year of Light and Light-Based Technologies (IYL 2015).