When you look up at the night sky, what do you see？ There are other(26)_____bodies out there besides the moon and stars. One of the most(27)_____of these is a comet.
Comets were formed around the same time the Earth was formed. They are(28)_____ice and other frozen liquids and gases.(29)_____these "dirty snowballs" begin to orbit the sun, just as the planets do.
As a comet gets closer to the sun, some gases in it begin to unfreeze. They(30)_____dust particles from the comet to form. a huge cloud. As the comet gets even nearer to the sun, a solar wind blows the cloud behind the comet, thus forming its tail. The tail and the(31)_____fuzzy atmosphere around a comet are(32)_____that can help identify this(33)_____in the night sky.
In any given year, about a dozen known comets come close to the sun in their orbits. The average person can’t see them all, of course. Usually there is only one or two a year bright enough to be seen with the(34)_____eye. Comet Hale-Bopp, discovered in 1995, was an unusually bright comet. Its orbit brought it(35)_____close to the Earth, within 122 million miles of it. But Hale-Bopp came a long way on its earthly visit. It won’t be back for another four thousand years or so.