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 his days shall the righteous flourish; and abundance
of peace so long as the moon endureth. - Psalm 72:7
IN THIS UPDATE
Lunar Eclipse -- Sunday Night, Starting Before Midnight
Flat Earth Lunar Eclipse????
It's been six months since the last newsletter. I spent the winter working on Measuring the Heavens, the sequel to our Signs & Seasons curriculum. I'm happy to report that the work went well and I wrote a good first
draft of nearly all the chapters for this volume. But progress has stalled right in the Epilogue now that the days of light and heat have arrived. Still hopeful to make forward progress over the summer so that this book might become a reality within a year or so.
This is so encouraging since this project has repeatedly stalled since Signs & Seasons was published in 2007. It was hard in those days to work and raise a
family while trying to run a homeschool publishing business on the side. But now that the kids are grown, there is more time for this project. I'm just hopeful to create at least this second volume of my originallly-planned five-volume series. And if the LORD allows, I'd be grateful to complete as many of those volumes as possible before shuffling off this mudball.
It is disappointing that so few Christian homeschoolers are interested in astronomy. It's an optional elective at best, casually overlooked by most. So many are unaware of the Biblical foundation and the prominent historical importance of Classical Astronomy, the basis of all timekeeping and navigation and the foundation
of modern physics.
Someone recently said to me that there is no point in astronomy as long as there is light pollution. This mentality is so false. There is a magnificent mathematical order in the observable sky, epsecially in the celestial clockwork of the Sun, Moon and planets -- seen in the daytime and even under light polluted city skies.
This mathematical magnificence on high reveals the Divine Mind of the Creator as nothing else in the natural world. As the Shepherd King of Israel wrote:
The heavens declare the glory of God; and the firmament sheweth his handywork. Day unto day uttereth speech, and night unto night sheweth knowledge. There is no speech nor language, where their voice is not heard. - Psalm
There is nothing else mentioned in Scripture that declares God's glory. How then can a believer be dismissive of the heavens? If we ignore the heavens, where else can we look in the creation for a declaration of God's glory?
The mathematical "knowledge" of the heavens is hiding in plain sight, and this will be the subject of Measuring the Heavens. But I have not personally heard actual "speech" coming from the heavens, at least not with my ears in a language I can understand. But perhaps the Heavenly Host still
Where wast thou when I laid the foundations of the earth? declare, if thou hast understanding.... When the morning stars sang together, and all the sons of God shouted for joy? - Job 38:4,7
The latter verse is portrayed in a most evocative manner in the creation of Narnia in C.S. Lewis' The Magician's Nephew. There is power in speech, as words were used by the Word to call forth the creation. But in order to know the message of the heavenly speech, to acquire the knowledge that is shown, one must
first make it a practice to observe and study the heavens that declare the glory.
For more information about topics from Classical Astronomy
discussed in this newsletter, please check out
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Lunar Eclipse -- Sunday Night, Starting Before Midnight
There will be total eclipse of the Moon this Sunday evening, May 15, 2022. This eclipse will begin before midnight, but mid-eclipse will occur after midnight. The date given for a lunar eclipse is always the date of mid-eclipse, since this is the precise moment of the Full Moon, or its opposition -- when the orbital
position of the Moon is fully opposite the position of the Sun. For this reason, the actual date given for this eclipse is Monday, May 16, though observers in North and South America will see the early phases of eclipse before midnight on Sunday, May 15.
The Moon's shadow includes a penumbra, or partial shadow and an umbra, or full shadow. The Moon enters these shadows during ingress and exits during egress. There is not much to see during the penumbral phases, just a subtle darkening along the Moon's limb. The umbra is visible
during partial and total phases since the darkness of the Moon's full shadow is upon the lunar surface.
The phases of eclipse are as follows, with times indicated:
P1 - first contact of the leading limb of the Moon with the penumbra during ingress -- 9:30PM EDT;
U1 - first contact of the leading limb of the Moon with the umbra - begin ingress partial eclipse -- 10:27PM EDT;
U2 - second contact - trailing limb of the Moon enters the umbra - begin total eclipse -- 11:28PM EDT;
MID - mid-eclipse, precise moment of lunar opposition -- 12:11AM EDT on Monday, May 16;
U3 - third contact - leading limb of the Moon enters the penumbra, egress - totality ends, begin egressing partial eclipse -- 12:54AM EDT;
U4 - fourth contact - trailing limb of the Moon enters the penumbra, partial eclipse ends, egressing penumbral phase begins -- 1:55AM EDT;
P4 - last contact of the trailing limb of the Moon with the penumbra, eclipse event ends -- 2:52AM EDT.
This eclipse favors American observers west of the Mississippi, though some parents east of the Mississippi might agree to keep their younger kids up at least until totality begins at midnight, eastern time.
Note the symbols shown in the image above for indicating the contacts of lunar eclipses. These symbols are conventionally used in the Astronomical Almanac, published annually by the U.S. Naval Observatory. These are like a convenient "shorthand" used to symbolically indicate these phases where space is at a premium.
This will be further explained below.
One important nugget of information provided for eclipses is the sublunar point. This is used to indicate the point on the globe of the Earth directly underneath the Moon, along a line extending from the center of the Earth. The figure above shows the sublunar point at the time of mid-eclipse. The sublunar
point shows the entire hemisphere of the globe centered around that point, and this hemisphere includes every location on the Earth where the eclipse is visible a that time.
The eclipse visibility map below is adapted from the 2022 Astronomical Almanac. The sublunar positions of the contact points are indicated with the symbols explained above. The shaded areas indicate boundaries along the Earth representing the hemipshere of the globe in which the eclipse will be visible during the times of
those resective contacts. So the P1 phase can be seen along a hemisphere including Saudi Arabia and Russia (where the Moon is setting) extending west to central North America (where the Moon is rising). And the U2 phase can be seen within a hemisphere extending from Africa and Europe west through the Pacific Northwest.
Everyone on Planet Earth within these hemispheres can confirm these facts with their own eyes. This is also confirmation that the Earth is a spherical globe, and not a flat plane as some contend. This topic will be explained in detail in the next section.
* * * * *
Throughout most pre-industrial history, commonplace eclipses had been regarded as "signs and wonders," harbingers of doom. So were comets and other natural phenomena. Scripture does indicate in Gen. 1:14 that the luminaries had been created for "signs and for seasons." Our Signs & Seasons curriculum presents many commonplace "signs" in the sky that demarcate the seasons and otherwise provide useful calendar and navigational information.
Some critics have argued with me that this is wrong, that Scripture teaches that the celestial bodies are only made for "signs and wonders." But it is just plainly evident that there are practical "signs" which provide information for timing the planting and harvesting of crops, among other
It's been my opinion that the "signs and wonders" of the end times as taught in Scripture will be supernatural occurrences in the sky, outside the normal natural functions, really big, really unnatural, and really undeniable by every eye that sees them. But perhaps we should not be too hasty to hold any preconceived
The star Betelgeuse in the constellation Orion became very dim in Janaury, 2020 to a level not known in all history. There was speculation that this star might soon explode in a supernova, though it was not expected to do so for ages. Nonetheless, I found it depressing to look upon this star and imagine it gone, the
appearance of Orion changed forever.
A rational explanation was put forth and soon Betelgeuse brightened to its former level. And yet this "sign" preceded the beginning of the COVID-19 debacle, surely the worst "pestilence" known in the current generation. Was the LORD trying to tell this skeptical generation something with the dimming of Betelgeuse?
Or was it just another "coincidence"? With our world today rapidly spiraling downhill, should we pay special attention to the specific timing of this lunar eclipse?
There are always bad things happening in the world, whether or not they coincide with an unusual celestial sighting. So perhaps the answer is the one we already know -- to remain vigilant and pray for the swift return of the LORD.
FLAT EARTH LUNAR ECLIPSE???
It's been almost a year since I got this email from Misty:
Wondering if you could debunk some of the flat earth tenets? It is becoming more and more popular and more and more developed.
I've had such requests for years. Honestly, I have no enthusiasm for tangling with flat earthers. I'd much rather devote my meager time to teaching facts than debunking nonsense. I've heard from a few flat earthers along the way who rained down hellfire and damnation on my head for teaching the facts about a
spherical Earth. But this lunar eclipse offers an opportunity to discuss one the more egregious absurdities of flat earth dogma.
Flat earthers start out in an honest place. It is true that many scientific conclusions are handed down on authority in our educational system without explanation or evidence. It's healthy to be skeptical and ask questions, since this is the foundation of the modern scientific method. But devout flat earthers become
hardened and entrenched, impervious to any open-minded discussion. Like all conspiracy theorists, they are shrill and strident. It's a waste of time trying to persuade them. But I agree with Misty that honest seekers of knowledge should be equipped with some facts.
For what it's worth, I briefly joined the Flat Earth Society in the 1980s, before starting Classical Astronomy. I read the newsletter and gave the group a fair hearing to see if they were on to something. But the "proofs" that were offered were infantile and easily answered, and simply avoided the really tough
questions. I let my membership lapse when some overtly racist things were said in their newsletter. I was not going to pay dues to such a group.
As explained in the previous section of this newsletter, the sublunar point on the Earth is the location directly under the Moon at any given time. It is the point on the Earth's surface crossed by a line extending from the center of the Earth to the center of the Moon. An observer at the sublunar point would see
the Moon directly overhead at the zenith. The Moon is only visible at that given time from the hemisphere of the Earth centered on the sublunar point.
The magnificent mathematical order of the heavens is based on the sphere. We live on a spherical Earth that appears to be in the center of the celestial sphere. It's clear to the eye that the Sun and Moon are spheres, as are the planets and their moons, viewed with the aid of the telescope. This is because of
Newton's law of gravity, in which matter distributes itself evenly around its center. This unversal spherical principle enables angle measurement and geometry, which are the basis of this mathematical order. Based on geometry, we can extend straight lines (or rays) between objects for making angular measurements.
We can observe the current position of the Sun along the celestial sphere. We can measure this position according to its declination and right ascension, which are coordinates in the equatorial coordinate system of the celestial sphere. This is the exact counterpart of the more familiar
terrestrial coordinate system of latitude and longitude.
We can use simple geometry to extend a ray from the Sun, backwards to locate the solar point , the equatorial coordinates of the Sun's current position. That same ray can extend forward in a straight line through the center of the Earth and off into space to a position in the sky called the antisolar
point. These two points are precisely 180 degrees from each other along the celestisl sphere. For example, as shown in the image below, if the solar point is on the celestial equator at the autumnal equinox, the antisolar point is 180 degrees away at the opposite point on the celestial equator, the point of the vernal equinox.
For the purpose of lunar eclipses, this ray between the solar point and the antisolar point is the umbral axis, the centerline upon which the cone of the Earth's umbra is centered. So the Earths' shadow extends directly away in the opposite direction from the Sun according to the very simple principles of geometrical
straight lines that even a child can understand.
The umbral axis extends from the solar point and intersects the Earth at the subsolar point representing the location on the Earth directly underneath the Sun. The Sun appears directly overhead at the zenith as observed from the subsolar point. Thus, the subsolar point is always in the tropics, somewhere
between the Tropic of Cancer and the Tropic of Capricorn.
The umbral axis entends through the center of the Earth and intersects with the Earth's surface again at the antisubsolar point, which is the opposite point on the globe from the subsolar point. So if the Sun is at the autumnal equinox, the subsolar point will be on the Equator, and the antisubsolar point will also be along
the Equator on the opposite side of the Earth. And the antisubsolar point is directly below the antisolar point so that someone standing at that location would have the Earth's umbra centered directly overhead at the zenith.
The flat earth scheme is a madcap concoction that cannot account for the geometric simplicity of the spherical model. According to the Flat Earth Wiki, the Sun and Moon are both objects 32 miles in diameter that somehow circle above the flat plane of the Earth at a distance of 3000 miles. Flat earth-ism teaches that the
Sun never actually rises and sets, but instead just appears when it's close to a location and disappears by receding into the distance. But this cockamamie idea is easily disproved by simple geometry. Perhaps this will be discussed on a future newsletter. Looking at this picture below, it should be clear that the rays of the Sun would shine down everywhere on the flat earth at the same time. You can draw a simple diagram showing that the Sun and Moon should be visible
above the flat earth at all times.
While flat earthers seem to agree that solar eclipses are caused by the interposition of the Moon between the Sun and Earth, they cannot explain lunar eclipses as caused by the interpositoin of the Earth between the Moon and Sun.
Flat earth-ism proposes that lunar eclipses are caused by some mysterious "shadow object" that is otherwise invisible and somehow only shows up to produce a lunar eclipse. It is hard to understand how such a "shadow object" can otherwise evade detection since the Moon and all the planets shine brightly under reflected light
from the Sun. The Moon itself is inherently quite dark, reflecting only 4% of the incident sunlight, about the same color as an asphalt parking lot. Even if this elusive "shadow object" reflected a fraction of a percent of sunlight, it should still be detectable with modern instruments. But according to flat earth-ism it remains conveniently out of sight at non-eclipse times.
In the flat earth scheme, the umbral axis of the "shadow object" is separate from the ray from the Sun to the subsolar point. There is no reason why the Sun and the umbra should align so closely with the precise longitudes and latitudes of the subsolar and antisubsolar points. And there is no way that the Sun and umbra
could align so closely along the declinations and right ascensions of the celestial sphere with solar and antisolar points.
Moreover, if the Sun and Moon were such small bodies, so close to the Earth, there would be much observable parallax with the background stars, and this would easily disprove this infantile scheme. Parallax is a topic flat earthers avoid. This topic would be too much to delve into in this newsletter, maybe another
Basically, flat earth-ism falls apart under a simple study of geometry. If anything, the growing pervasiveness of this teaching reflects the deplorable state of American education, since flat earthers admit their confusion with any sort of mathematics. Instead, they usually offer elaborate talk-arounds to sidestep dealing
with the actual issues.
So anyway, hope the above explanation was beneficial.
Til next time, God bless and clear skies,
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