Question

Question #71218

Answer 1

Light travels at 299,792,458 metres per second in a vacuum.

The definition of a vacuum is: "A space entirely devoid of matter."

So, light travels at 299,792,458 metres per second in a vacuum, but how many km per second does it travel in a vacuum?

Let's work on a few calculations...

1 metre = 1/1000 of a kilometre

Therefore:

299,792,458 metres = 299,792,458 * 1/1000 kilometres

This means that:

299,792,458 metres = 299,792.458 kilometres

So it can be said that light travels at approximately 300,000 kilometres per second.