What is a Comet?
Dear Digger Doug,
What is a comet?
—Alethea, age 6, Morgantown, KY
Thanks for your great question. Several years ago, a friend of mine, Kyle Butt, wrote an article about comets in Discovery magazine and answered your question. Here is how he put it:
Have you ever seen a comet yourself? They really are amazing. They look like huge shooting stars that stay in the sky much longer than a regular shooting star.Sometimes comets can be seen for several days at a time. What is a comet, and why do they only show up in the sky occasionally? Scientists believe that comets are huge balls of dust and ice. Because of this ice-dust mixture, people sometimes call them dirty snowballs or dirty ice balls. There are hundreds of comets. In fact, over 800 comets have been recorded. Some of these are called periodic comets, which means that they orbit the Sun in less than 200 years. Most of the time, we cannot see comets. But when they move close to the Sun, the heat causes them to evaporate. When a comet evaporates, a long tail is formed that is made up of tiny dust particles and gases. Sunlight reflects off these particles and makes it possible for us to see the comet and tail. The tails of some comets can reach many millions of miles long, making them the biggest objects in the solar system. Some scientists think that comets were formed millions of years ago by accident, but that cannot be true. Think about Halley's Comet, probably the most famous comet of all. It can be seen like clockwork every 76 years. How could an accident form a comet that has such a regular orbit? Furthermore, no accident billions of years ago could produce the natural laws needed to form comets and keep them in orbit. In truth, God made the Universe, our Galaxy, the solar system, and everything in it. As the psalmist wrote long ago, “The heavens declare the glory of God; and the firmament shows His handiwork” (Psalm 19:1).