In 1930 astronomer Clyde Tombaugh discovered the dwarf planet Pluto while looking at photographs of the night sky.
1930年，天文学家克莱德·汤博在研究夜空照片的时候发现了矮行星冥王星。
In 1930, astronomer Clyde Tombaugh discovered the dwarf planet Pluto while looking at photographs of the night sky.
1930年天文学家克莱德·汤博就是研究了夜空的图片后发现了矮行星冥王星。
Janhunen says it would take a 440-pound (200-kilogram) spacecraft using an electric sail less than five years to travel between Earth and dwarf planet Pluto.
Janhunen说，采用该电驱动帆作为动力，440磅(200千克)重的航天器从地球飞到冥王星所需时间少于5年。
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