To find life on worlds beyond the solar system, look for the color. Some microscopic organisms are brightly colored — pink, yellow, orange, green, and other vivid hues. If these organisms congregate in large areas on other worlds, they could show up in images from future telescopes. Astronomers have discovered more than 5,000 exoplanets — worlds in other star systems. With our current telescopes, we can’t see any of them as more than bright dots of light — no details at all. Most current efforts to find life are looking for the chemical markers of life in planetary atmospheres — a combination of oxygen and methane, for example. But astronomers are designing big new telescopes that could give us crude pictures of some of these planets. In recent years, a couple of studies have looked at the colors of microorganisms here on Earth. One study looked at organisms on land. The other took samples from in and around Hudson Bay in Canada. Researchers analyzed the colors and what might make them
