61 Cygni is about 720,000 astronomical units away.

61天鹅座我们大有72万天文。

Scientists call this distance one astronomical unit, or AU.

科学家们将这个定为天文，或缩写为 AU。

AU meaning astronomical unit, which is the distance between the Earth and the Sun, which means that Voyager 1 is 138 times further away from us than the Sun is.

AU 是天文，是地球到阳的平均（合 1.496 亿公里），也就是说旅行者 1 号我们的是阳的 138 倍。

Then Jupiter's right there at 5-point something, and then Saturn is about 10 astronomical units from the Sun.

然后这边的木星到阳有5 个天文左右的，之后土星到阳的大概有10 个天文。

Finally, after all these centuries, the astronomical unit was nailed down.

几个世纪后，这个天文于被确定下来。

It is currently almost 140 astronomical units away from our sun, meaning that it's 140 times farther away from the sun than earth is.

目前它阳的接近 140 个天文，这意味着它阳的是地球阳的 140 倍。

Mind you, not “an” astronomical unit — “the” one.

注意，不是“一个”（an）天文，而是“一”（one）。

That's why knowing the length of the astronomical unit is so important!

这就是为什么知道天文的长度是如此重要的原因！

When a comet approaches the Sun within a few astronomical units, solar heating causes the release of gases and dust from its surface, a process known as cometary outgassing.

当彗星接近阳几亿公里范围内时，阳的热量会导致其表面气体和尘埃释放，这个过程被称为彗星喷气。

It was travelling at an incredible speed of 540 million  kilometres per year, or 3.6 Astronomical Units, an astronomical unit being the distance between  Earth and the Sun.

它正以惊人的速度——每年5.4亿公里，即3.6个天文——疾驰，这里的一个天文指的是地球与阳之间的。

For context, one astronomical unit is  the distance from the earth to the sun, so four hundred astronomical units is  about ten times the orbit of pluto.

就上下文而言， 一个天文是从地球到阳的，因此四百个天文大是冥王星轨道的十倍。

No one can have a hand that's larger than the height of the atmosphere or an astronomical unit.

没有人能有比大气层高度或一个天文更大的手掌。

We call that one astronomical unit.

我们称其为一个天文。

Supermassive black holes have masses from a  hundred thousand times the mass of the sun to tens of billions of solar masses and are so big they  get as big as four hundred astronomical units.

超大质量黑洞的质量从阳质量的十万倍到数百亿倍阳质量不等，其大小可达四百个天文。

To be  precise, X7 has grown from a width of 0.25 arc seconds in 2003 to over 0.4 arcseconds  in 2021, corresponding to a spread of around 3300 Astronomical units.

确切地说， X7的宽度从2003年的0.25角秒增长到2021年的0.4角秒以上，相当于扩展了大3300天文。

The binary stars are separated by a distance of 97 astronomical units.

这两颗恒星相97个天文。

Even the farthest planet, TRAPPIST-1h, orbits at a distance of only 0.062 astronomical units, six times closer to its star than Mercury is to the Sun.

即使是最远的行星TRAPPIST-1h，其轨道也只有0.062个天文，比水星到阳的近六倍。

While the primary companions lie within two astronomical units of the star, the tertiary companions can be as far as 20 astronomical units.

虽然主要伴星于恒星的两个天文内，但第三伴星可以达到 20 个天文。