|
马上注册,结交更多好友,享用更多功能,让你轻松玩转社区
您需要 登录 才可以下载或查看,没有账号?立即注册
×
It gets stranger. Our sun is relatively young in the lifespan of the universe. There are far older stars with far older Earth-like planets, which should in theory mean civilizations far more advanced than our own. As an example, let’s compare our 4.54-billion-year-old Earth to a hypothetical 8-billion-year-old Planet X. |
情况变得复杂了。太阳相对于宇宙来说还很年轻,理论来讲年老恒星的类地行星上外星文明应该比地球文明更先进。假设有一个80亿年的行星X,我们用它和我们4.54亿年的地球做比较。 |
|
|