In the autumn of 1965 a surprisingly bright comet delighted the world as it passed very close to the sun. The comet brightened intensely as it neared the sun and was even visible to some people during the day. After its close brush with the sun, Comet Ikeya-Seki rapidly faded, but not before it put on a fine show for weeks. Or should I say, they put on a fine show? The sun’s tidal force ripped the comet into three pieces.
Comet Ikeya-Seki is a recent example of the most spectacular type of comet, called sun grazers. As you may guess from the name, sun-grazing comets pass very close to the sun. Such close encounters threaten to break up or totally destroy sun-grazing comets, but traveling so close to the sun can also make them light up the heavens. Unfortunately, we still have much more to learn about their composition and changeable paths, so it’s difficult to predict their brightness. Each time a comet appears, we just have to wait and see what it does.
This autumn promises another opportunity to see a spectacular comet. A year ago a group of Russian astronomers detected a faint comet, now dubbed Comet ISON, barreling toward the sun. It will pass nearest the sun on November 28. Though it will be visible for weeks leading up to its close encounter, Comet ISON likely will be seen best in the morning sky a few weeks after it grazes the sun.
Comet ISON has an orbit very similar to that of the Great Comet of 1680. And that comet passed closest to the sun on December 18, suggesting very similar circumstances to ISON. The Great Comet of 1680 was one of the brightest comets of the seventeenth century, briefly visible during the day and flaunting a spectacularly long tail. The first comet to be detected and tracked by telescope, the 1680 comet became known as Newton’s Comet because Sir Isaac Newton (a young-earth creationist) used its elliptical path to test and confirm Kepler’s laws of planetary motion.
What are comets? Astronomers think that comets are “dirty snowballs.” The snowball is only a few miles across, made of various ices, such as water, dry ice, methane, and ammonia. Mixed in are many dark, tiny particles that astronomers call dust.
A comet spends most of the time far from the sun, where it is very cold, so the ice remains frozen. As it passes close to the sun, however, the temperature rises to the point that much of the ices begin evaporating into a gas. In the vacuum of space the gas rapidly expands thousands of miles in every direction. The sun’s ultraviolet radiation charges the gas (in a process called ionization), which causes it to glow. This accounts for much of a comet’s brightness. Solar wind and radiation blow the gas and dust away from the sun to form the comet’s tail.
Because comets lose so much of their already miniscule mass each time they pass the sun, their lifetime must be very short. In fact, secular astronomers agree that it is far less than the supposed 4.5-billion-year age that they propose for the solar system. Of course, a short lifespan isn’t a problem if the solar system is only a few thousand years old as the Bible indicates.
Most scientists think that comets, as well as the rest of the solar system,
formed from a nebula 4.5 billion years ago, so how do scientists explain the
survival of comets today if the solar system is billions of years old? They
argue that Comet ISON must have been knocked loose from the supposed Oort Cloud,
a group of frozen snowballs that safely orbit far from the sun. But there is
no evidence that the Oort Cloud even exists. Along with their value “
and for seasons” (Genesis 1:14), perhaps one reason God made comets was to demonstrate
that the solar system is young.
So as you watch Comet ISON in November and December, you might want to talk
about comets’ cosmic significance with your friends. Reflect upon the fact that
God made comets for the same reason He made everything else in the universe,
including you and me: with the purpose of glorifying Him. Besides, “
He has made
everything beautiful in its time” (Ecclesiastes 3:11). This comet may exist,
in part, because God wanted you to think about Him and His creation and to use
this opportunity to share with others His glorious plan for the universe, including
the gospel of Jesus Christ.
Will this comet live up to expectations? We don’t know. But if you want to keep updated on what’s happening with Comet ISON, frequently check my blog at http://blogs.answersingenesis.org/blogs/danny-faulkner/
ISON’s Long Journey to the Sun
Halley’s Comet, which passes the sun every 75 years or so, is called a short-period comet because its path stays within our solar system. In contrast, long-period comets like ISON come from far away.
Where do these distant comets come from? That’s a problem for secular astronomers, who believe the solar system formed billions of years ago. Comets can’t survive that long, so they assume long-term comets must come from a theorized Oort Cloud, located at the fringes of the solar system. They believe these snowballs are leftovers from the solar system’s evolution, and periodically some are kicked out of deep freeze to begin a journey to the sun.
The Bible, in contrast, tells us where all the celestial bodies came from: God filled the heavens on Day Four of Creation Week. So the “survival” of long-term comets over the past 6,000 years isn’t a problem for biblical astronomers.