Darwin Flotilla- One Proposal to Detect ET

Darwin observes in the infrared since life on Earth leaves its mark at these wavelengths. On Earth, biological activity produces gases that mingle with our atmosphere. For example, plants give out oxygen and animals expel carbon dioxide and methane. These gases, and other substances, such as water, leave their fingerprints by absorbing certain wavelengths of infrared light. Darwin will split the light from an extrasolar planet into its constituent wavelengths, using an instrument called a spectrometer. This will show the drop in light caused by specific gases being in the atmosphere, allowing them to be identified. If they are the same as those produced by life on Earth, rather than by non-biological processes, Darwin will have found evidence for life on another world.