We have the mass of the sun, we have the radius of the sun so you can calculate the moment of inertia of the sun.

我们知道太阳的质量，太阳的半径,所以可以计算出,太阳的惯性是多少。

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Astronomers generally measure the size of stars in terms of the radius of our sun.

天文学家一般以太阳的半径为基本单位表征恒星的大小。

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The sun will then become what's called a red giant, and its radius will reach just past the orbit of Venus.

太阳就变成了所谓哦红巨星，它的半径将会达到以前金星的运行轨道。

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But there is a way to counter the increasing brightness of the Sun, the scientists believe - just increase the radius of the Earth's orbit!

BBC: Blue Marble Nasa