Speed of light - Wikipedia The speed of light in vacuum, often called simply speed of light and commonly denoted c, is a universal physical constant exactly equal to 299,792,458 metres per second (approximately 1 billion kilometres per hour; 700 million miles per hour)
How Fast Does Light Travel? | The Speed of Light - Space Light is a "universal speed limit" and, according to Einstein's theory of relativity, is the fastest speed in the universe: 300,000 kilometers per second (186,000 miles per second)
What Is the Speed of Light? - Science Notes and Projects The speed of light is the rate at which light travels The speed of light in a vacuum is a constant value that is denoted by the letter c and is defined as exactly 299,792,458 meters per second
The Speed of Light: Why It’s the Ultimate Speed Limit From the earliest experiments to the latest discoveries in cosmology and quantum mechanics, the speed of light remains the ultimate speed limit—an elegant, immutable boundary that continues to inspire wonder, challenge our intellect, and shape the very nature of reality
All About the Speed of Light and What It Measures - ThoughtCo The speed of light is the fastest known speed in the universe and is a cosmic limit Light travels at 299,792,458 meters per second in a vacuum, but it slows in different materials The speed of light helps measure cosmic distances, illustrating the universe's vast size and age