Absolute Magnitude
- Astronomers measure the brightness of stars at a standard distance using the absolute magnitude scale
- This is because a really bright star far away will look the same as a dim star nearby, so it is difficult to measure the brightness directly
- This scale runs back to front:
- The brighter the star, the smaller the magnitude
- The dimmer the star, the larger the magnitude
- The brightness of a star depends on two main factors:
- How much light the star emits
- How far away the star is (more distant stars are usually fainter than nearby stars)
Examples of the apparent magnitude of different bodies in the Solar System
- The absolute magnitude of stars is a measure of how bright they would be if they were all the same distance away from Earth
- More specifically, if it was 10 parsecs (32.6 light-years or 3.04 × 1014 km) away from the Earth
