Objects look very different at different wavelength. First of four images of the Sun, this one made using visible light Second of four images of the Sun, this one made using ultraviolet light. Third of four images of the Sun, this one made using X rays. Fourth of four images of the Sun, this one made using radio waves. By studying the similarities and differences among these views of the same object, important clues to its structure and composition can be found.
Car lights a long way away appear faint.
This relation is very important for astronomers because sometimes we actually know the intrinsic amount of light celestial objects emit. Remember that determination of astronomical distances is always one of the most difficult problems. I o is called a Standard Candle . Blackbody Radiation There are different ways for matter to emit light. That means different physical processes.