Nothing we know of can travel faster than light.
An object traveling at the speed of light can travel around the world about seven and a half times in one second.
The light from the sun, 93 million miles (150 million kilometers) away, takes only about eight minutes to reach the earth. A vehicle traveling at 620 miles (1,000 kilometers) per hour would take about 17 years to make the same journey!
In empty space where there is no air, light travels at 186,282 miles (299,792 kilometers) per second. Air slows light down, by about 57 miles (92 kilometers) per second. Glass slows it down much more, to about 122,140 miles (197,000 kilometers) per second.
When light travels through a substance, it slows down only as it passes through the substance. When it reaches the other side, it speeds up again.
As light travels through the lens of your eye, for example, it slows down and is refracted.
This means the direction of the light is changed. Astronomers who study the stars through telescopes and photographers who use cameras depend on light to slow down as it travels through a glass lens.
