Finding Another Earth

NASA will unveil a potentially exciting discovery on Thursday （July 23） regarding the search for alien planets. In a teleconference at 12 p.m. EDT （1600 GMT） tomorrow， the space agency will announce new findings made by the planet-hunting Kepler Space Telescope. You can tune in to the announcementlive via an online audio feed provided by NASA. A statement from NASA announcing the teleconference [远程电信会议] did not provide any additional details as to what new information will be unveiled.

“Exoplanets [系外行星]， especiallysmall Earth-size worlds， belonged within the realm of science fiction just 21 years ago，”according to the NASA statement. “Today， and thousands of discoveries later， astronomersare on the cusp [尖端] of finding something people have dreamed about for thousands of years-another Earth.” Participants in the teleconference will be John Grunsfeld， anassociate administrator for NASAs Science Mission Directorate in Washington; JonJenkins， Kepler data analysis lead at NASAs Ames Research Center in Moffett Field， California; Jeff Coughlin， a Kepler researchscientist at the SETI Institute in Mountain View， California; and Didier Queloz， a professor of astrophysics[天体学] at the University of Cambridge， United Kingdom.

The $600 million Kepler Space Telescope was launched in 2009 with the goal of studying the diversity of planet systems in the MilkyWay galaxy. In addition， the mission aimedto find rocky， Earth-Iike planets orbiting their parent stars at a distance where liquid water could form （the so-called “habitable zone，” or“Goldilocks zone”）.

The telescope detects planets with the so-called “transit” method： When a planetpasses in front of its parent star， partially blocking its light， Kepler observes the tiny dipin the stars brightness. Kepler has detected 4，661 planet candidates， of which 1，028 have been confirmed. In May 2013， Keplerended the first phase of its mission when thesecond of four “reaction wheels” failed on the spacecraft. The reaction wheels are devicesresembling a gyroscope[陀螺儀] that maintain Keplers position in space.