- 积分
- 17983
- 威望
- 17983
- 包包
- 26159
|
[hide][/hide]1 D8 e# U) c: Z8 `1 m/ d# K2 A
Hundreds of extrasolar planets have been found since the first confirmed discoveries in the mid-1990s. Many of them are large 'hot Jupiters', but steady improvements in observational capabilities have brought physicists closer to detecting smaller Earth-sized bodies, and now, the planet-hunting space observatory Kepler has discovered two in orbit around the Sun-like star Kepler-20. Planet Kepler-20 f has a radius almost identical to that of Earth, and Kepler-20 e is slightly smaller, at 0.87 times Earth's radius. The radii of the planets and the architecture of the system — at least three larger planets orbit the host star — suggest that the Earth-sized planets are rocky, and that the outer planet (Kepler-20 f) may have developed a thick atmosphere of water vapour.
- {# `4 K2 G- t1 x4 y0 G; ?, l+ J4 ]3 N* P7 Y! l2 H. ?8 B
5 A1 x9 k4 j+ a* P6 k |
附件: 你需要登录才可以下载或查看附件。没有帐号?注册
-
总评分: 威望 + 20
包包 + 20
查看全部评分
|