How fast is light?
For grown-ups: the science
Light is so fast that it can zoom all the way around the Earth seven times in just one second!
In empty space, light travels about 299,792 kilometers every second. Since the Earth's circumference is about 40,000 kilometers, light can circle it roughly 7.5 times in a single second. Sunlight takes an average of about 8 minutes and 19 seconds to reach Earth, which we rounded to about 8 minutes 20 seconds for the video.
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Transcript
Look how that beam zooms around and around the Earth... just how fast is light, really?
Light can zip all the way around the Earth seven times in just one second. That means light moves incredibly, incredibly fast.
Sunlight also has to travel through space to reach us. It takes about eight minutes and twenty seconds to get all the way to Earth.
The starlight you see at night left its star a long, long time ago. The farther away a star is, the older the light looks by the time it reaches you.
Light is so fast, it can zip all the way around the Earth seven times in just one second.