Live Science: Enormous 3D map of the universe shows brilliant 'sea of light' near the cosmic dawn
Enormous 3D map of the universe shows brilliant 'sea of light' near the cosmic dawn
Light, visible light, or visible radiation is electromagnetic radiation that can be perceived by the human eye. [1][2] Visible light spans the visible spectrum and is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 terahertz.
Light is a primary tool for perceiving the world and interacting with it for many organisms. Light from the Sun warms the Earth, drives global weather patterns, and initiates the life-sustaining process of photosynthesis; about 10 22 joules of solar radiant energy reach Earth each day.
Light is a transverse, electromagnetic wave that can be seen by a typical human. Wavelengths in the range of 400–700 nm are normally thought of as light.
And what are some of the common properties of light, such as absorption, reflection, refraction and diffraction? You might think scientists know all the answers, but light continues to surprise them.
Simply stated, light is nature's way of transferring energy through space. We can complicate it by talking about interacting electric and magnetic fields, quantum mechanics, and all of that, but just remember-- light is energy. Light travels very rapidly, but it does have a finite velocity.
In common usage, the term light (or visible light) refers to electromagnetic radiation in a wavelength range that is visible to the human eye (about 400–700 nanometers (nm) (15.7-27.6 millionths of an inch)).