Background:科学家近日通过“开普勒”太空望远镜观测到一个距离地球2000光年的奇特行星系统。其恒星与太阳相似，并有6颗行星围绕它运行。

Finding six new planets around a single star represents animpressive haul. Nasa is calling it the best find since the firstso-called ‘exoplanet’ was discovered 16 years ago. It might not be the most populated solar system yet found - six or possibly seven planets have been found in a rival system, but it's the nature of this new discovery which is getting the astronomers scratching their heads in wonder.

That's strange, because small hot planets this close in should have been ripped asunder by their parent star in their formative years, say the scientists. One possible explanation is that the planets started out bigger and further out and were slowly dragged into tighter orbits, as part of a contracting belt of dust and asteroids.