标题: 难题300：Recent observations suggest that small [打印本页] 作者: 语法学习爱好者 时间: 2019-10-20 21:26 标题: 难题300：Recent observations suggest that small Recent observations suggest that small, earthlike worlds form a very low percentage of the planets orbiting stars in the galaxy other than the sun. Of over two hundred planets that astronomers have detected around other stars, almost all are hundreds of times larger and heavier than the earth and orbit stars much smaller than the sun.
Which of the following, if true, would most weaken the above justification of the claim that earthlike worlds form a low percentage of the total number of planets?
There are millions of planets orbiting stars around which astronomers have not attempted to detect planets.
The best current astronomical theories predict that almost all planets around other stars are probably hundreds of times larger than the earth.
A planet orbiting a star similar to the sun would be more likely to be earthlike in size than would a planet orbiting a much smaller star.
The smaller a planet is relative to the star it orbits, the more difficult it is for astronomers to detect.
The observations would have detected any small, earthlike worlds orbiting the stars around which larger planets have been detected.
