1. How far is a light year?
2. The star Vega is 27 light years from earth. How far away is Vega in metres?
3. The star Pollux is 3·78 x1017 m from earth. How far is this in light years?
4. The star Beta Centauri is 300 light years from earth. How long does it take light to travel from this star to the earth?
5. An astronomer on Earth views the planet Pluto through a telescope. Pluto is 5 763 x 106 km from earth. How long did it take for the light from Pluto to reach the telescope?
6. Our galaxy, the Milky Way, is approximately 100 000 light years in diameter. How wide is our galaxy in kilometres?
7. The nearest star to our solar system is Proxima Centuri which is 3·99 x1016 m away. How far is this in light years?
8. Andromeda (M31) is the nearest galaxy to the Milky Way and can just be seen with the naked eye.
Andromeda is 2·1 x 1022 m away from the Milky Way. How long does it take for light from Andromeda to reach our galaxy?
9. The Sun is the nearest star to the planet Earth. It takes light 8·3 minutes to reach us from the Sun. Use this information to find out the distance from the Earth to the Sun in kilometres?
10. Sir William Herschel, an amateur astronomer, discovered the planet Uranus in March 1781. Uranus is 2 871 x 106 km away from the sun. How long does it take for sunlight to reach Uranus?
