A leap second is added in order to keep UTC within 0.9 seconds of observed astronomical time.

添加闰秒是为了将UTC保持在观察到的天文时间的0.9秒范围内。

youdao

The second was the first use of an astronomical telescope by Galileo Galilei.

另一个重大发现则是伽利略•加利雷首次使用天文望远镜。

youdao

The second asteroid belt lies at about 20 astronomical units from the star, or a position comparable to Uranus in our solar system.

第二个行星带距离它的恒星为20个天文单位，这相当于太阳系中天王星的位置。

youdao

Del Sol Medical Center in El Paso snared second place with an astronomical 45% operating margin.

FORBES: Health Care