Smithsonian.com

Artist's conception of a red dwarf star and a planet (credit: NASA, ESA and G. Bacon (STScI))

There may be as many as three times more stars in the universe as astronomers previously though, according to new study published by Nature.

Pieter G. van Dokkum of Yale University and Charlie Conroy of the Harvard-Smithsonian Center for Astrophysics looked for red dwarf stars—which are about 10 to 20 percent as massive as our Sun and much more faint—in elliptical galaxies around 50 million to 300 million light years from us. Because of their small size and dimness, scientists hadn’t been able to detect red dwarfs in any but the nearest galaxies, including our own, and so no one really knew how abundant they were.

The astronomers found that the red dwarf stars were around 20 times more common in the elliptical galaxies than in the Milky Way, which is a spiral galaxy. “We usually assume other galaxies look like our own,” Conroy said. “But this suggests other conditions are possible in other galaxies.”

The discovery of these stars implies that there could be far more planets in the universe, including more planets that could contain life. Red dwarfs are usually more than 10 billion years old, which is plenty of time for life to have evolved.

More stars in the universe could also have another implication—there could be less dark matter than astrophysicts have calculated. At least some dark matter, a mysterious substance that has mass but cannot be detected with current technology, could simply be stars, the astronomers say.