How do we know that the Earth is a smaller ball turning around one of those stars, the Sun?

我们怎么知道地球是一个更小的球，绕着其中一颗恒星——太阳转呢？

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The sun was a huge ball of fire low on the horizon.

落在地平线上的太阳像个大火球。

《牛津词典》

The sun was now sinking, a fiery ball of light in the west.

西边的太阳像一个发光的火球正在下沉。

《牛津词典》

A comet is a huge ball of frozen gas and dust that often releases a long trail of material as it nears the sun.

VOA: special.2009.09.30

At the other end, City keeper David James fumbled a James Coppinger strike while Claudio Reyna wasted two half chances before Sun hammered the ball against the woodwork from Lee Croft's pass.

BBC: SPORT | Football | League Cup | Doncaster 1-1 Man City (aet)

"You wake up in the morning at about 5 o'clock ... and then you watch the sun rise and this extremely peaceful and serene atmosphere and then you just look at the sun coming like a ball of fire, rising from the sand and then coming up, " recalls Jibunoh.

CNN: Sahara explorer taming the desert

"The poor kid simply lost the ball in the sun, " said Cubs Manager Joe McCarthy.

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