Astronomers can use algebra to figure out the intensity of a star compared to another star. Here's how:
The light spreads equally in a sphere around the light source. So if the radius of that sphere is A and the radius of a bigger sphere around it is B.
The light always stays the same, it's just how far away you see it from. if X is the light from A and Y is the light from B, the equation is: (2 is squared)
X/Y=(B2/A2)
But if you figure out the distance you are viewing from. Lets say B is 10 light years and A is 5 light years, the equation becomes:
X/Y=(102/52) or X/Y=100/25 or X/Y=4
That means at 5 light years away the star is 4 times more intense than at 10 light years away.
