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 easier to see from many light-years away. They found that colors were more intense under drier conditions. So life might show up better on a planet like Mars than one like Earth.
But they found that large enough patches of many of the organisms could be easy to see whether it was dry or wet — like algal blooms in Earth’s oceans. So to find evidence of extraterrestrial life, future telescopes may look for the color.
Script by Damond Benningfield
Today's program was made possible by Mercer Caverns, in Calaveras County in California's historic Gold Country.