Earth circle

土圜───Earth circle

They are to attempt to be the first to circle the Earth non-stop by balloon.───他们将试图成为首批乘热气球不间断环球飞行的人。

look at the motion of the planets in the sky, you will find that they don't simply go around the earth in a continuous circle.───抬头仰望天空中行星的运动，你将会发现它们并不是简单地绕着地球旋转。

That's enough to circle the Earth twice.───这足够绕地球两圈了。