Question: How fast is the speed of light?

The current best estimate for the speed of light is 299, 792, 458 metres per second. This is the speed of light in a perfect vacuum. When light travels in any sort of medium (air, glass, water etc) it is slowed down. In physics we write the speed of light as the constant “c”. Many things I could say about light and the consequences of its constant nature (see my other posts on special relativity). However, to put the speed of light in human terms, it is approximately 300,000 km per second. The fastest I’ve ever traveled (relative to the surface of the Earth) is in an airplane traveling at ~1,000 km per hour. This corresponds to ~0.0001% the speed of light. The Earth moves around the Sun at about 30 km per second, so that is 0.01% the speed of light.