雅思阅读练习及答案：Search begins for Earth

　　Search begins for 'Earth' beyond solar system

　　Staff and agencies

　　Wednesday December 27, 2006

　　Guardian Unlimited

　　1. A European spacecraft took off today to spearhead the search for another "Earth" among the stars.

　　2. The Corot space telescope blasted off aboard a Russian Soyuz rocket from the Baikonur cosmodrome in Kazakhstan shortly after 2.20pm.

　　3. Corot, short for convection rotation and planetary transits, is the first instrument capable of finding small rocky planets beyond the solar system. Any such planet situated in the right orbit stands a good chance of having liquid water on its surface, and quite possibly life, although a leading scientist involved in the project said it was unlikely to find "any little green men".

　　4. Developed by the French space agency, CNES, and partnered by the European Space Agency (ESA), Austria, Belgium, Germany, Brazil and Spain, Corot will monitor around 120,000 stars with its 27cm telescope from a polar orbit 514 miles above the Earth. Over two and a half years, it will focus on five to six different areas of the sky, measuring the brightness of about 10,000 stars every 512 seconds.

　　5. "At the present moment we are hoping to find out more about the nature of planets around stars which are potential habitats. We are looking at habitable planets, not inhabited planets. We are not going to find any little green men," Professor Ian Roxburgh, an ESA scientist who has been involved with Corot since its inception, told the BBC Radio 4 Today programme.

　　6. Prof Roxburgh said it was hoped Corot would find "rocky planets that could develop an atmosphere and, if they are the right distance from their parent star, they could have water".

　　7. To search for planets, the telescope will look for the dimming of starlight caused when an object passes in front of a star, known as a "transit". Although it will take more sophisticated space telescopes planned in the next 10 years to confirm the presence of an Earth-like planet with oxygen and liquid water, Corot will let scientists know where to point their lenses.

　　8. Measurements of minute changes in brightness will enable scientists to detect giant Jupiter-like gas planets as well as small rocky ones. It is the rocky planets - that could be no bigger than about twice the size of the Earth - which will cause the most excitement. Scientists expect to find between 10 and 40 of these smaller planets.

　　9. Corot will also probe into stellar interiors by studying the acoustic waves that ripple across the surface of stars, a technique called "asteroseismology".