My orbital period is 247 years.

我的轨道周期是 247 年。

Only 12 or so have orbital periods below 75 minutes.

只有12种左右的激变变星拥有低于75分钟的轨道周期。

If they have orbital period less than 200 years, they're called short-period comets.

如果它们的轨道周期小于200年，就被称为短周期彗星。

The fastest known orbital period among binary stars is just five minutes and 21 seconds.

双星系统中已知最快的轨道周期只有5分21秒。

For one thing, the orbital period turns out to be just a little over 4.23 days.

首先，其公转周期仅仅是4.23天多一点。

Tidal forces rapidly synchronized the Moon's spin and orbital period, so that one face always pointed toward Earth.

引潮力迅速同步了月球的自转与公转，因此月球总是以同一面指向地球。

An asteroid at that distance would have an orbital period of about 4 years: a simple fraction of Jupiter's 12 year period.

在这个距离范围内的小行星的轨公转周期约为4年——仅为木星12年轨道周期的一小段。

As it moved farther away, the time it took to orbit once around the Earth increased: its orbital period got longer.

随着月球离地球越来越远，它绕地球公转的时间就增加了：它的轨道周期变长了。

Unfortunately, Mars and Earth are separated by millions of kilometers and orbital periods that leave only a narrow travel window every two years.

不幸的是，火星和地球相隔数百万公里，二者的轨道周期芝士每两年才会有一个狭窄的旅行窗口。

These binary pulsars afford a second set of identifiers: the orbital period of the system, which does not change over billions of years.

这种系统的轨道周期在数十亿年内都不会改变。

The two stars orbit each other every 51 minutes in one of the fastest orbital periods known for a rare kind of binary star.

这两颗恒星每51分钟绕对方公转一次，其轨道周期是一种罕见双星系统中已知最快的轨道周期之一。

Specifically, in a geosynchronous orbit about 35,000 kilometers above the Earth where its orbital period matches Earth’s rotational period.

具体来说，在地球上空约 35, 000 公里的地球同步轨道上，其轨道周期与地球的自转周期相匹配。

This is called tidal locking, and it's worked on nearly every big moon in the solar system; tides from their home planet have matched their spin and orbital period.

这被称为潮汐锁定，太阳系中几乎所有的大型卫星都受此影响；来自母星的引潮力使得它们的自转和公转周期一致。