Looking into space

We can't travel to stars to study them-it'd take thousands of years. All we can do is measure the electromagnetic radiation coming from them.

Radiation can tell us a lot about stars ad galaxies

• We can tell a lot about a star by studying the electromagnetic (EM) radiation it emits (gives out)
• You can get an idea of how far away a star is by measuring the light radiation coming from it (its brightness)
• A star that looks very bright on Earth could be either quite close to Earth but not very bright, OR a long way away and very bright
• But astronomers know how much radiation certain types of stars actually emit
• So by seeing how bright they look from Earth, they can tell how far away those stars must be
• You can also use parallax to measure the distance to nearby stars
• Parallax is when…