Apparent Magnitude:

Apparent Magnitude Is the brightness of a star seen from the earth. There are instuments that people use to to measure the light from the stars, even if the stars are billions of light-years away. Apparent Magnitude dates way back to the greek astronomer Hipparchus. Hipparchus labeled the brightest star "Magnitude 1", and on all the way to "magnitude 6" which is the weakest stars.

In this picture you can see there are brighter stars and lighter stars. This picture was created by Cole McConnell