Because simple lifeforms are small, because immense distances separate us and other planets, and because of interference from light emissions coming from the sun and other stars, astrobiologists are not able to simply zoom in with high-powered telescopes to look for plants and animals on the surface of distant planets. As a result, they primarily make use of spectroscopy, which examines light emission and absorption patterns at various wavelengths as it interacts with different forms of matter, on what is a rapidly expanding list of exoplanets.
