Comets

Early Studies were connected with the origin of short-period comets.

早期的研究是为了探讨短周期彗星的起源.

In addition, there are thousands of small bodies as asteroids and comets.

此外, 被发现的还有成千上万的小型天体像是小行星和彗星.

Comets are usually made of ice and rock.

彗星通常是由岩石和冰构成的.

As comets go, it is a whopper.

就彗星而言，它可是个庞然大物。

We can see comets only when they come close to the earth.

只有当彗星接近地球时,我们才能看得见它们.

There are about 800 comets whose orbits are known.

人类已经知道有运行轨道的彗星大约有800颗.

We need to study more comets.

我们需要研究更多的首星.

The earth crosses the tracks of certain comets.

地球穿过某些彗星的轨迹线.

Most stars probably have their quota of planets, meteorids, comets, and asteroids.

多数恒星也许还拥有若干行星 、 流星 、 彗星和小行星.

Any school kid can tell you that comets are made of ice.

随便找个小学生都会告诉你,彗星是由冰组成的.

Scientists want to learn how comets come into being.

科学家们想了解彗星是怎么形成的.

The night sky is occasionally host to the transient visitors known as comets and meteors.

夜空有时还接待如彗星和流星那样的过路来访者.

Perhaps, extinctions are caused by something outside, like comets and asteroids.

也许, 灭绝是由外来物体引起的, 比如彗星和小行星.

They were stars, I knew, and flaring comets, that peopled my flight among the suns.

我知道是这些星辰和闪烁的慧星遍布在我飞行恒星之间的航程中.

These small objects, including asteroids, Kuiper Belt objects, comets and interstellar dust.

这些小天体包括小行星 、 柯伊伯带的天体 、 彗星和星际尘埃.