Signal in the noise

Here's a fun picture - the big solid bright line you see above is the main light from the far away star, and the color represents the wavelength of the visible light. Slightly above the main band, however, there is another band, and this is the spectrum from an orbiting exoplanet -- the first time we've been able to see an exoplanet's spectrum

Evaluating these spectrums is extremely important in astronomy, as you learn two very important facts - the motion/speed of the object, and its composition. Redder lights means the object is moving away, bluer lights means is moving towards us; individual elements reflect light differently, so it is possible to asses what the object is composed of by analyzing its spectrum of light.

Cool, right?