interesting facts about light
November 12, 2009 | In: Science facts
Light is electromagnetic radiation, just like radiowaves, infrared radiation and x-rays.
Even though light travels at 299,792,458 meters per second (in a vacuum), it takes it years to travel across the vast distances in space.
It takes about 1.3 seconds for light or radio waves to reach us from the Moon.
Nothing travels faster than light.
Light takes four and half years to travel to the nearest star (other than the Sun), 100,000 years to travel across the width of the galaxy, and 100 billion years to travel across the observable Universe. (source)
A light-year (the distance light travels in one year), equals about 6 trillion miles.
Red, green and blue are the primary colours of light. Mixing them in various ways will make all other colours, including white.
Our main source of light on Earth comes from the Sun.
The earliest known artificial light sources were stone lamps, first invented about 40,000 years ago in Ice-Age Europe. They were probably fueled by animal fat, with bits of bark or lichen for a wick.
The simplest ones were little more than slabs of sandstone or limestone. They were very inefficient, and the melted fuel simply ran off the stone, wasted.Others had bowl-shaped depressions to hold the fuel, and some had carved handles that allowed the lamps to be moved while lit without burning the owner.