Distances in space are so vast that the fastest thing in the Universe,
light is used to measure them – the speed of light is
186,282 miles per second!
- one light second is the distance that light travels in one second – 300 million metres / 1,864 million miles.
- one light-year is the distance that light travels in one year – 5.92 trillion miles!
- “light-years” are one of the standard distance measurements in astronomy.
- it takes nearly eight and half minutes for light from our Sun to reach Earth.
- light-travel takes 4.22 years to reach Earth from the nearest star -Proxima Centauri, this mean more than 25 trillion miles!
- viewed from earth, Proxima Centauri looks like it was 4.22 years ago because its light takes 4.22 years to Earth.
- astronomers use parsecs to measure distances – originally came from parallax shift measurements (see Distances page); a light year is 0.3066 parsecs.
This below table shows how long the Light Year takes light to travel from the Sun to all our Solar System planets and dwarf plant*.
Mercury – 3 minutes 2 seconds
Venus – 6 minutes 1 second
Earth – 8 minutes 3 seconds
Mars – 12 minutes 6 seconds
Jupiter – 43 minutes 2 seconds
Saturn – 1 hour 19 minutes 3 seconds
Uranus – 2 hours 39 minutes 6 seconds
Neptune – 4 hours 1 minute
Pluto* – 5 hours 5 minutes