According to a new proposal from astronomers and professors Avi Loeb and Dan Maoz, signs of life may be awaiting detection in the shadows of death. Looking to the abundance of dying stars known as white dwarfs, Loeb and Maoz devised a simple way to search for oxygen in the atmosphere of exoplanets which orbit around white dwarfs much the way Earth orbits the sun. Loeb says the theory could yield results within the decade with the launch of NASA’s James Webb Telescope in 2018.
The pair published a paper in February, ”Detecting bio-markers in habitable-zone earths transiting white dwarfs,” outlining their theoretical research. In it, Loeb, chair of Harvard University’s department of Astronomy and director of the Institute for Theory and Computation (ITC) within the Harvard-Smithsonian Center for Astrophysics, explains that though a white dwarf is simply the cooling core of a dead star, its radiant heat and light can host life on orbiting planets for billions of years.
“We know of a few thousand of those planets by now and there must be many more out there. And a key question is, if a planet is quite similar to Earth in terms of its rocky material; and if it’s the right distance from the furnace, the central star that keeps it warm so that adequate water can exist on its surface; would the chemistry of life naturally arise, and would life exist the same way it does on Earth?” Loeb says it’s a difficult question to address with theory alone. “The best way to approach it,” he says, “would be to try and observe other planets, and search for indications of life.” And that rather than visiting those places, Loeb recommends searching “for signatures of molecules that are naturally produced by life and the most generic one is oxygen.”
Recent research suggests not only that there are plenty of exoplanets out there like our own, but that they are often paired with and orbiting white dwarfs. According to Loeb, “Somewhere between 15 to 30 percent of [white dwarfs] show evidence of rocky material on their surface, and such material would not be there unless there was rocky stuff around them,” meaning that these are the exoplanets that could potentially sustain life.
( via blogs.smithsonianmag.com )