Nothing can travel faster than the speed of light.
It moves through space at 300 million metres per second.
In one year, light travels: 9,460,730,473,000,000 metres!
Astronomers use light years to measure the enormous distances in space.
Using metres, or even kilometres, just isn't practical.
Light travels 300,000,000 metres per second. About the distance from the Earth to the Moon
Although light travels very quickly, distances in space are vast.
It takes 8.3 minutes for light to travel from the Sun to the Earth.
This means we don't see things as they happen – a sudden change in the Sun's brightness would take 8.3 minutes to be visible on Earth.
Our nearest star after the Sun is Proxima Centauri, which is 4.2 light years away.
Proxima Centauri, 4.2 light years from Earth
When we see it at night, the light we see actually left the star 4.2 years ago.
Despite the speed of light, the vast scale of our Solar System means that when we look into space, we are actually looking back in time.