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This is the Classical Astronomy Update, an email newsletter especially
for Christian homeschool families (though everyone is welcome!)
Please feel free to share this with any interested friends.
IN THIS UPDATE:
- Announcements
- Classical Astronomy Yahoo Group
- Featured Item - Hugg-A-Planet
- Dance of the Planets
- Venus, the Moon, and Antares - October 31
- Venus and Jupiter Approach
- Astronomy Topics
- Calculating Precession (A Reader Question)
Dominion and fear are with him, he maketh peace in his high places.
Is there any number of his armies? and upon whom doth not his
light arise? How then can man be justified with God? or how
can he be clean that is born of a woman? Behold even to
the moon, and it shineth not; yea, the stars are not pure
in his sight. How much less man, that is a worm? and
the son of man, which is a worm? - Job 25:2-6
Welcome to the Classical Astronomy Update!
Hello Friends,
Back in the summer, we made a couple animated features called The Sky This Month showing some timely celestial events. Some folks wrote to express their appreciation for these animations and others since have written to ask when the series will continue. I'm sorry to report that that there are no immediate plans to continue with that series. When I got a new computer recently, the original files for those videos somehow got corrupted, and I'd have to start from scratch in relearning how to make new movies.
Besides, it took about 25 hours each to create those 4 minute videos, and I just don't have that much time to spare each month. Sorry folks, I'm a one-man band with a homeschool family and a day job! If you missed those animations, some low-quality versions of The Sky This Month videos are posted at our family's YouTube account. Thanks for your interest.
Announcements
Classical Astronomy Yahoo Group
We've had a lot of fun discussing astronomy topics with everyone over at the Classical Astronomy Yahoo group. Update readers and some other friends have gotten to know each other a bit, and we share info on upcoming sky events when there's not enough time to write a newsletter.
Many people in the group are new to astronomy and the best part is being able to share the excitement when people discover new things in the sky for the first time. Here's a recent post from Rose in in Chicopee, Massachusettes:
I SAW VENUS!!!!
And yes, I'm shouting because I'm so excited. We went on a hay ride with the youth group last night. At around 6:30 my husband pointed to the sky and asked, Is that Jupiter? At first I said, yes, I think so but it seems so low. So I looked around and higher in the sky and more to the south was another bright "star." I knew that one was Jupiter so I began to think of the discussions on this list and knew we had talked about Venus. But I was so certain I'd never be able to see it because it is so low on the horizon and we are so close to city lights and surrounded by trees and tall buildings, so I was not sure it was Venus.
I told my kids to take a good look because it could very well be Venus and we would check when we got home. How exciting to look at the star chart and see that at exactly the time we were looking, Venus was exactly in that spot!!! So it was Venus.
I'm so happy that I joined this group and paid attention to the discussions or I would not really have known that it was Venus.
There you have it! Another satisfied customer! If you'd like to participate in the conversation, join the Classical Astronomy Yahoo group. If you don't want to get a lot of loop emails, you can sign up for a daily digest or you can read the posts online (which requires a Yahoo account.)
Featured Item -- Hugg-A-Planet -- Online Ordering from Fourth Day Press
Folks, we still have a lot of closeout items to unload from our online store. These items would make great Christmas presents for that space cadet on your shopping list! One item we'd really like to move is our inventory of Hugg-A-Planets. These soft, plush globes, are lots of fun and make an ideal educational gift for that budding genius on your list! !
Hugg-A-Planet plush globes are like stuffed animals in the shape of planets! Now you can be like Al Gore and hug your very own planet! Or, you can also take your planet and kick it across the room! While we don't recommend such rough treatment of this product, your little astronomer or geographer can learn lots about our world from studying the information printed on their Hugg-A-Planet globes.
 Hugg-A-Star
This stuffed celestial globe depicts the actual stars against a dark blue night sky, and includes the Milky Way, the celestial equator, and the path of Halley's Comet through the heavens!
Your young stargazer can actually learn the positions of the constellations in the sky with this nifty little globe. And unlike those pricey ceramic celestial globes, this one doesn't shatter if it ever crashes to the floor!
 Hugg-A-ConstellationThis stuffed constellation globe includes much useful information about the constellations. It includes the same information as the Hugg-A-Star except that the constellations are color-coded for easier reference. The constellations of the zodiac (i.e., along the plane of the solar system) are highlighted in yellow. The constellations to the north are in red, and those to the south are in green. The globe includes the Milky Way, the celestial equator, and the path of Halley's Comet, giving you a star map that you can take outside or just toss across the room!
 Hugg-A-Planet EarthThis plush terrestrial globe includes quite a bit of geo-physical information about the Earth. 500 places are labeled, including natural features such as, rivers, mountains, deserts, vegetation, islands, and even population densities. Not just a toy, this is an actual world globe, one that won't break if the baby plays with it!
We're asking $12.00 each for these Hugg-A-Planet globes, compared to $19.95 from the manufacturer or from Amazon.com. Plus, our shipping rate for these items is a bargain. Folks, these are priced to move! Don't be the last one on your block to get your very own Hugg-A-Planet!!!
For a complete list of all our currently available products, check out the main page and left sidebar in our Online Ordering page.
Dance of the Planets
Venus, the Moon, and Antares - October 31
The summer constellation Scorpius is currently drawing west toward the sunset with the annual progression of the seasons. Meanwhile, the bright planet Venus is currently rising higher in the western sky as it emerges further from behind the Sun. Also, the Moon continues its monthly swing around the Earth, tracing its circular path across the sky. They all meet this month.
Each month, the Moon passes bright Venus as these bodies fall into the same line of sight as seen from the Earth. This month, on the evening of Friday, October 31, the Moon lines up near the bright first magnitude star Antares, the brightest star in the constellation Scorpius, not far from bright Venus.
The next evening, November 1, the waxing crescent Moon will make its closest pass of Venus, coming to within six lunar diameters of the bright planet. If your area is blessed with clear skies, be sure to observe this beautiful passing.
There might be some out there that wonder if there is any evil, mystical significance to the fact that these bodies line up on the evening when the world celebrates Halloween. We have always counseled Christians that astrology is a silly, antique supersitition, and that these alignments mean nothing at all except that these celestial bodies are following the paths ordained by the LORD. The fact that this conjunction occurs on October 31 means nothing more than a date on the calendar. As the LORD spoke through His prophet:
Thus saith the LORD, Learn not the way of the heathen, and be not dismayed at the signs of heaven; for the heathen are dismayed at them. - Jeremiah 10:2
For more information on our approach to these subjects, check out our Pagan Influences? series.
Venus and Jupiter Approach
Keep watching Venus and Jupiter throughout the fall. Venus and Jupiter are both visible in the evening sky. Jupiter is currently drawing toward the Sun as the Earth swings around the other side. Meanwhile, and Venus is currently emerging from behind the Sun and pulling away from the sunset with each passing day during the month of November.
Throughout November, Jupiter and Venus will appear to draw closer together. Over a span of weeks, Jupiter will be lower in the southwestern sky after sunset while Venus will be higher.
Finally, on the evening of December 1, Venus and Jupiter will make their closest approach, and will be a pair of glittering celestial jewels adorning the evening sky in the fading twilight. If that's not exciting enough, Jupiter and Venus will be joined by the four-day-old waxing crescent Moon. So the three brightest objects in the sky after the Sun will be sparkling over the western horizon in evening twilight.
Folks, this is an excellent opportunity to observe the clockwork of the heavens in action. Make it a point to notice Jupiter and Venus draw closer on clear evenings throughout November. Tell your friends, family, and neighbors and share this info with your homeschool support group. People are always amazed to see the planets and this is a rare show that you won't want to miss!
Astronomy Topics
Calculating Precession (A Reader Question)
We received this question from Andy:
I'm reading a book called "The Astronomy of the Bible" by E.W. Maunder. In it he makes a case for the classical constellations being established somewhere around 40 degrees north latitude and about the year 2700 BC. This may be too technical for your newsletter but I was wondering how you would go about calculating the precession of the earth's axis and the positions of the celestial poles and equator that far back in time without errors taking over your calculations (or is there a resource that you know of that would explain this). Thanks, Andy
Hi Andy, thanks for this excellent question. Maunder's book is excellent, both scientifically and Biblically.
The short answer is that precession is a very even, precise motion that has a very predictable amount of movement over the span of millennia. It only amounts to about 1 arcminute every 72 years. We have reliable astronomy measurements dating back to about 200 B.C. that clearly indicate the precise positions of the solstices in Cancer and Capricornus, compared to Gemini and Sagittarius where they are today. So if we can reliably go back 2300 years, it's not too hard to extrapolate another 2100 years beyond that. Other historical clues suggest that the ancients identified a northern star called Thuban in Draco as the pole star, which would have been true in about 2000 B.C. based on the current rate of precession.
Another indication is that precession is linked to the pattern of eclipses. Modern chronology has successfully dated every eclipse recorded in ancient writings. Indeed, the "official" dates given to events in ancient history (such as the birth of Jesus) are based on a careful comparison to these documented eclipses. Precession is caused by the Moon's gravity tugging on the Earth, continually deflecting the axis and causing the apparent shift in the constellations of the equinoxes and solstices over many centuries.
However, the Earth's gravity is also tugging back on the Moon in its orbit, causing a phenomenon called "regression of the nodes" which essentially means that the Moon moves such that eclipses can occur along any position of the ecliptic over predictable intervals of time. (For more on this, see the update article Eclipses - Why Not Every Month?)
All of the above was realized by Isaac Newton in about A.D. 1687. The tremendous triumph of Newton's law of universal gravitation was that all these apparently unrelated, anomalous phenomena were shown to be interrelated through the common cause of gravitational interactions of the Earth and Moon. Also, Newton showed that these phenomena were very precise and predictable and confirmable by many diverse sources of fact.
It was because of this sort of accuracy that modern science originally became enshrined as a source of authority in western culture. Ironically, over the centuries since Newton, science has become sloppy and lazy in comparison (hence darwinism and the materialistic, mechanistic "proofs" thereof.) This might become more apparent if students begin to learn more about classical science and the history of science.
At any rate, our standard unit of time is the "tropical year," which measures the time between vernal equinoxes and acounts for the tiny amount of precession. The tropical year has been measured at 365.2424 days, and is found to be the most precise, unvarying quantity observed in nature.
So anyway, given all this hard scientific data, it's not unreasonable to extrapolate back to 2700 B.C. as Maunder pointed out in his book. But it is a very good practice for Christians to be critical thinkers and ask the tough questions and expect a complete answer in reply. So many thanks Andy for your question!
Coming in future Classical Astronomy Updates:
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Jupiter, Venus and the Moon will pass each other on the evening of Monday, December 1.
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We hope to explain about light pollution and how street lighting can spoil the quality of the night sky.
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In 2009, we will celebrate the Quadricentennials of Galileo and Kepler.
Til next time, God bless and clear skies!
-jay
The Ryan Family
Cleveland, Ohio, USA
When I consider thy heavens, the work of thy fingers, the moon and
the stars, which thou hast ordained, what is man that thou art
mindful of him? and the son of man, that thou visitest him?
- Psalm 8:3,4, a Psalm of David
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