The comets are coming, the comets are coming, prof says

"But there is much more beauty," said Tom Gehrels, a planetary sciences professor and leader on the Space Watch Team, which keeps watch on near-stellar objects from a Kitt Peak National Observatory telescope.

Gehrels said he recently christened a new Space Watch scope atop Kitt Peak that uses a computer to scan the sky.

The computer scans help researchers see moving objects in space and identify those that are unknown, including asteroids and comets.

Comets are essentially asteroids that have ice trapped inside.

As they approach the sun, the ice is transformed to gas, which escapes through the back of the asteroid, forming the tail commonly seen in photographs.

On a clear winter night, the computer can pick up 1,000 space objects, but usually 700 of those have already been discovered.

In addition to the beauty of these celestial bodies, there is a danger, too, Gehrels told the crowd of 200 gathered for his speech.

"It looks like we're fighting a war, and we are," he said of the telescope project.

He said asteroids hit the Earth with greater frequency than some realize, citing a large meteorite that struck near the Yucatan Peninsula 65 million years ago and a 1954 meteorite that hit an Alabama woman in the leg as she sat in her living room.

He said meteorites 1-kilometer across typically hit Earth at a rate of one every million years.

But he cautioned, "Please don't think once in a million years is something you don't have to worry about."

Despite the danger, Gehrels said humans are capable of stopping meteors before reaching Earth by using rockets.

After the speech, Melissa Meister, a women's studies senior, said, "The combination of beauty and danger is very appropriate to the topic. It reaffirms the interconnectedness of all things."

She added that everything beautiful, from roses to humans to asteroids, is also dangerous.