Everything that has a temperature different than the absolute zero (0 Kelvin degree) emits radiant energy.
Radiant energy was discovered by Sir William Crookes in 1875.
The radiant energy is a natural energy. It can be gathered directly from the environment.
This is the energy of electromagnetic waves including X-rays, microwaves and light.
The microwaves and radio waves are invisible for us.
Nikola Tesla is one of the greatest scientist that had study the radiant energy. The first wireless phone has been invented from him and it was based on the radiant energy and its physical characteristics.
As example sources of radiant energy can be placed: light, solar energy, X-rays, Radio waves, ultraviolet rays, infrared rays.
The utilization of the solar energy for heating and electricity production is also based on the radiant energy.
Natural light energy comes from the Sun.
As a whole the light is energy. This is a nature way for transferring energy through the space really quickly. The speed of light in vacuum is around 299 792 458 m/s.
Electromagnetic spectrum is the distribution of electromagnetic radiation according to energy.
Visible light is a really small part of that spectrum.
Each of the colors from the spectrum corresponds to a different wavelength of light.
Picture source: wwww.hyperphysics.phy-astr.gsu.edu
Measurement of lighting
It’s a little bit confusing and complicated when we ever tried to compare flashlights or lighting of any kind. There are so many confusing terms like lumen and lux that we are supposed to know and to use properly. The main three of them are:
Candela indicates the strenght of the light emission.
Lumen describes the ammount of light that is radiated.
Lux indicated the illumination intensity of an area.