Astronomy from de Harward Crimson 03-12-2010.

More Stars Found in Universe

Scientists discover ten times more stars than previous estimate

By KELLY K. W. LAM, CONTRIBUTING WRITER

Published: Friday, December 03, 2010

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300,000,000,000,000,000,000,000—that is the latest estimate of the number of stars in the universe, a number three times larger than scientists’ previous approximations, according to a new study published in the journal Nature on Wednesday.

By analyzing red dwarfs—the most common type of star in the vicinity of the Milky Way—the researchers found that there are about ten times as many of these stars as astronomers had previously thought, which has led to the new estimate of the existence of 300 sextillion total stars.

Charlie Conroy, a junior fellow at the Harvard-Smithsonian Center for Astrophysics, and Pieter van Dokkum, professor of astronomy at Yale University, measured the strength of certain light given off by red dwarfs in eight nearby elliptical galaxies to draw a direct estimate of their abundance. Elliptical galaxies are older celestial bodies and tend to contain larger numbers of red dwarfs.

Due to red dwarfs’ relatively small mass and dimness compared to larger stars like the sun, they emit longer wavelengths of light that are difficult for astronomers to detect. But using advanced telescopes at the Keck Observatory in Hawaii, scientists were able to more accurately detect these stars, Conroy said.

Since the eight elliptical galaxies measured by the researchers are located between 50 million and 300 million light-years away from the Milky Way the results do not directly impact the way we think about our own galaxy, according to Conroy. Our own galaxy, the Milky Way, is a spiral galaxy, and red dwarfs tend to cluster in elliptical galaxies.

But the discovery of abundant red dwarfs in elliptical galaxies indicates that there may be less dark matter—a mysterious substance detected by its gravitational effect—than scientists had previously estimated.

Because dark matter gives indirect clues to star formation activity over time, the new findings will significantly challenge the way astrophysicists had previously expected the way stars and galaxies form, Conroy said.

Furthermore, because planets capable of supporting life orbit stars, the findings could suggest that there is a higher possibility of finding other inhabitable planets, van Dokkum said in an interview with the Keck Observatory.