【科学60秒】繁星满天 (双语有声)

It's Even More Full of Stars

To many who stare up at the heavens, the stars may seem simply uncountable. Of course that’s not the attitude of astronomers. But they’ve made a discovery that means there are probably a lot more stars in the universe than they thought.

Red dwarfs are stars that are only 10 to 20 percent as massive as our sun. They’re so faint that astronomers weren’t able to detect them in any galaxies other than our own Milky Way, and neighboring ones.

So researchers used sensitive instruments at the Keck Observatory in Hawaii. They found faint signatures of these red dwarf stars in eight massive elliptical galaxies relatively close to us—between 50 million and 300 million light-years away. And they discovered that these galaxies were home to 20 times as many red dwarfs as there are in the Milky Way.

The finding leads astronomers to believe that there may be three times as many stars in the universe as they’d previously theorized. The research was published in the journal Nature.

And a recently discovered exoplanet orbiting a red dwarf had some Earth-like qualities. Lead researcher Pieter van Dokkum says there could be trillions of Earths orbiting the ubiquitous red dwarfs.