The ideal discovery would be a planet similar in composition to Earth that lies within the Goldilocks Zone and orbits a stable star.
理想的情况是这样的：在居住区内发现和地球组成结构类似的行星，并且围绕稳定的恒星公转。
2
HD 189733b is a hot Jupiter - a planet similar in mass to Jupiter in our Solar System, but one that orbits much closer to its star, and so is much hotter.
HD 189733 b是一个炽热的木星——一颗和太阳系中的木星极为相似的行星，但是它绕行的轨道更接近与它的恒星，因此比木星更为炎热。
3
The nucleus consists of uncharged neutrons and positively charged protons. negatively charged electrons travel around the nucleus in their orbits, similar to the way planets moving around the sun.