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Comet Ison

High School Science
Psalm 19:1 says “The heavens declare the glory of God; And the firmament shows His handiwork.” This is what makes stargazing such a profound experience, in my opinion, because as we look at the night sky, we are being reminded of the creative power and glory of God.

This is especially true when something can be seen in the sky which is a little bit different. One reasonably common occurrence would be the appearance of a comet. And in just a few weeks time, we are hoping that we will get to see a pretty spectacular display, caused by Comet Ison.

This will be the 4th major comet of my lifetime. I am hoping that it will be the second that I can actually see!

Comets I Have Seen

Comet Hale Bopp

Comet Hale Bopp, Tandragee, Northern Ireland, UK 1997

In 1973, there was a lot of hype about the arrival of Comet Kohoutek. But this turned out to be much, much less spectacular than predicted.

The regular 75-year orbit of Comet Halley brought this famous comet back in 1986 for the poorest showing in a thousand years! I saw it through a telescope, but didn’t get to see it by eye. Comet Halley has had so many noteworthy appearances in history that it is not possible to list them all; but here are a few. The appearance in 240BC is noted in the Chinese chronicle Shiji. The 1066AD appearance was shortly before the successful invasion of England by the Normans under William I. The 1301 appearance was seen by the artist Giotto di Bondone, who painted the comet as if it were the Star of Bethlehem, in his famous Nativity. A European space mission to Comet Halley in 1986 was named Giotto in his honor. Giotto was mistaken, however. The nearest appearance of the comet to Jesus’ birth was 12BC – too early to be a possible date for the nativity.

My favorite comet sighting was in 1997, when Comet Hale-Bopp was clearly seen in the Northern Hemisphere. The photo on this page shows the comet over Tandragee Presbyterian Church, in Tandragee, Northern Ireland. It was taken by Roy Vogan, and supplied to me by my friend Robin Greer, who was, at that time, pastor of the church in the photo. At the time, I was Head of Science at a government high school in Pontllanfraith, Wales. As the school was built on a hillside, and my laboratory was near the top end of the school, there was a clear view of the early evening sky, when the comet was at its brightest.

Comet Ison

Comet Ison

Comet Ison from the Hubble Space Telescope,4/10/2013

Comet Ison was only discovered in September 2012. It was reported visible to the naked eye on November 8th 2013. It reaches perihelion (closest point to the sun) on November 28th 2013, and should be at its best visibility shortly after that. It is a “sun-grazer”, which means that it has a highly hyperbolic orbit, and will pass closer to the sun that most comets. Its actual brightness is very difficult to predict. It could be the brightest for 100 years, or it could be as disappointing as Kohoutek.

What causes the tail?

The tail always points away from the sun. It is caused by gas driven away from the comet by solar plasma streams. It is interesting to observe the tails, because they obviously constitute material that the comet is losing. In fact, at the rate of loss of material, it would not be possible for any “short-period” comets, like Comet Halley, still to exist after 10,000 years. This fact puts an upper boundary on the possible age for the solar system. Yet astro-physicists assume that the solar system is 4.6 billion years old. For this reason, they assume that there must be a cloud of comets out beyond the edge of the solar system, called the Oort Cloud. Comets from this cloud get nudged every few thousand years by a passing star, and begin to orbit the sun. Yet there is no observational evidence for the existence of an Oort Cloud.

Given that the Bible gives the Earth some 6,000 years only for its current age, we have a better explanation for why we continue to see short period comets. As for Comet Ison, I really hope it puts on a good display for us. Comets are fun and beautiful. They also remind us of the glory of God and His creative power, and their existence is completely consistent with what we expect from the bible being true.


For further information, and up to date news on the progress of Comet Ison, Dr. Danny Faulkner, Astronomer in Residence at Answers in Genesis, Kentucky, is keeping a blog. I will be checking there regularly, and suggest that you do the same, by following the links provided.

Further information on finding other objects in the night sky can be found by buying The Stargazer’s Guide to the Night Sky by Dr. Jason Lisle.

Stargazer's Guide to the Night Sky

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