Easy come, easy go. On this date in 2005, astronomers announced the discovery of Eris, a heavenly body slightly larger than Pluto, and called it the 10th planet.

• 来得快；去得快；在2005年的今天；天文学家宣布发现了厄里斯星；这个小的天体比冥王星大；我们叫它第10颗行星.