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Three Intriguing Lunar Inquiries
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Analytical Insight into the Wonders of Creation, with Aubrey Falconer
Submitted By admin on 10/02/16
Aubrey Falconer, admin, Documents, articles, science, theology, physics, astronomy 
This Document originally posted in the "Aubrey Falconer" Group

Composite photograph of Moon. Credit: T.A. Rector, I.P. Dell'Antonio, NOAO, AURA, NSF
 

I was recently invited to contribute a regular column to a friend's bimonthly newsletter, and this constitites my first entry. Hope you find it insightful! In the future, I plan to cover a variety of topics such as amazing creatures, the nature of reality and determination of truth, economics, and anything else which happens to interest me.

All the best,

-Aubrey
 
 
 
1) Why is the full Moon so wonderfully bright?

As astute readers have doubtless observed, the illumination provided by a "full" Moon is significantly greater than that which is furnished when a portion of the Moon is cloaked in shadow. While a full Moon can bathe the countryside in light, a half Moon can scarcely enable you to stumble about in inky darkness! This phenomenon is labeled as "Opposition Spike", and is due to the fascinating optical properties of our nearest celestial companion.

The Sun always illuminates the half of the Moon which is facing it - and when we on Earth perceive the Moon to be "full", it is because the Earth is nearly in line between the Sun and Moon and we are observing the same portion of the Moon which is lighted by the Sun. This is described as a low "phase angle", and is the key to understanding opposition spike.

If the Moon's phase angle were near zero, a flag erected upon the center of the visible area of the Moon would point towards the sun, and would cast a shadow straight below itself - you wouldn't be able to see it. Likewise, the smaller the area of the visible portion of the Moon illuminated by the Sun, the larger and more visible the flag's shadow would be due to the greater phase angle of the Sun's light.
 
Lunar Phases
Source: Wikipedia
The Moon's surface is essentially rough and irregular regolith (composed of finely pulverized rock) - and in the near absence of a dense atmosphere and accompanying diffuse light scattering, it reflects light from the sun in a retroreflective fashion from every surface on which the Sun shines.
 
When the light from the Sun cast onto the Moon is at a high phase angle from our point of observation on the Earth, a large portion of the illuminated area we can see is actually in shadow due to the bumps, craters, and other large and small irregularities on the Moon's surface. When the Moon is at a low phase angle and appears "full" from Earth, the shadows are much smaller - and thus, the amount of light reflected to the Earth is significantly greater.


2) Is the Moon escaping from the Earth?

While it is a fact that the distance between the Earth and the Moon increases with every passing moment, the two heavenly bodies are actually linked in a kinetic energy exchange that gradually slows the rotation of the Earth, and accelerates the moon - flinging it farther out into space. The mechanism which causes this phenomena - tidal acceleration - is both surprising and fascinating!

As Earth's oceans (and even landmass, to a lesser degree) are drawn towards the Moon by gravitational forces, the mass of the material in the Earth's "tidal bulge" moves Earth's "center of gravity" away from the Earth's geometrical center, and nearer to the Moon. The Earth and Moon orbit each other around a point known as a "barycenter", which is inside the Earth's surface but offset from it's center - and which has the effect of forming a tidal bulge on the Earth opposite to the Moon due to centrifugal forces in addition to the tide facing the Moon due to direct gravitational attraction. The bulge facing the Moon is the most important, because it is nearer to the Moon - and therefore experiences a greater gravitational attraction which more than cancels out the effects of it's companion on the other side of the Earth. Since the Moon's prograde (in the direction of the Earth's own rotation) orbit is slower than the rotation of the Earth, the Earth's center of gravity is constantly shifted ahead of the Moon's path, pulling the Moon along it's course faster and faster at the expense of the Earth's own rotational speed. Since tidal effects involve friction while reshaping a planet, energy is lost from the dynamic system in the form of heat - but mathematical models predict that it would still take billions of years for the Earth's spin and Moon's orbit to finally synchronize and eliminate tidal acceleration.

In essence, the Moon is receding - but it isn't escaping.
 
 

3) Is the Moon a product of billions of years of random chance?

Atheistic explanations for the existence of the universe all involve gradual processes operating over inconceivably large periods of time, so observations we can make which cast aspersions on the possibility of our universe having existed for the requisite duration present significant impediments to atheistic worldviews. Putting our newly acquired knowledge of tidal acceleration to a practical use, let's determine the maximum possible time that the Moon could have been orbiting the Earth:

Since the Moon is currently receding from the Earth at a speed of 1.5 inches per year, and the Moon averages a distance of 238,857 mi from the Earth, we can perform a simple linear extrapolation to determine that the Moon would have been touching the Earth around 10 billion years ago if it's speed remained constant:
238,857 / (2.36742424 × 10^-5) = 1.00893197 × 1010

This sounds like an awfully long time, because it is! The assumption we made about the Moon's speed being a constant was a serious oversimplification. As we are aware, the Moon is accelerated by the Earth's tides - which are a product of the Moon's gravity, which is inversely proportional to the cube of the distance between the two bodies, which results in the Moon's recession rate being roughly inversely proportional to the sixth power of the distance. "In the Beginning", by Dr. Walt Brown, includes an iterative computer model which simulates the Earth / Moon relationship in much greater detail than the primitive example included above, and which returns a maximum of 1.2 billion years that the Moon could have been orbiting the Earth. Naturalistic explanations for the origin of the Moon generally involve the Moon being flung from the Earth while in a molten state after being impacted by a smaller planetary body - but they have a very difficult time explaining why the Moon's orbit is so nearly circular, and how the Moon's current distance from Earth is consistent with a gradual recession over the course of 4+ billion years.

While the age of the Moon is certainly an encouragement to the creationist worldview, there is an another entire class of arguments which is even more compelling! It is known as the "Anthropic Principle" - the idea that no matter where scientists look, they find every parameter in our universe finely tuned for the viability and enjoyment of mankind.

Even taking the atomic properties and incredibly ordered physical laws of our universe for granted - the type and mass of our Sun, the Earth’s mass and distance from our Sun, The Earth's axial tilt, rotation period, magnetic field, crust thickness, oxygen/nitrogen ratio, water vapour and ozone levels - and much, much more are all "just right"! Our Moon plays an incredibly important role for life on Earth as well - providing tides which are strong enough to prevent Earth's oceans from stagnating and killing the marine vegetation which produce much of the oxygen we breath, but also gentle enough to avoid inundating the Earth multiple times a day.

Auspicious as the Moon is, it's not just it's practical aspects which are so remarkable. Assembled below is a collection of several amazing facts relating to the relationships between the Moon, Earth, and Sun - much of which was based upon research contained in "Who Built the Moon", by Christopher Knight and Alan Butler. Does this look like coincidence to you?
  • Total Solar Eclipse
    Source: Miloslav Druckmüller
    The Moon orbits the Earth every 27.3 days, and is 27.3% of the Earth’s size.
    1737 / 6371 = .273

  • The Earth revolves nearly 366 times in one orbit of the Sun, and is 366% larger than the Moon.
    6371 / 1737 = 3.66

  • 366 orbits of the Moon are equal to 10,000 days on Earth.
    27.321 * 366 = 9999.48


  • The Moon's mass is 1.23% of the Earth's mass.
    (7.3477 * 10^22) / (5.9736 * 10^24) = 0.0123

  • The Moon's orbital period multiplied by 4 is the exact number of times which the Sun is larger than the Earth, and also the number of Sun widths which the Earth is distanced from the Sun at the aphelion (farthest point) in it's orbit.
    1392000 * 27.32 * 4 = 152,117,760

  • The circumference of the Earth multiplied by that of the Moon and divided by 100 is greater than 99.7% equal to the exact circumference of the Sun.
    40,041.47 * 10908.36 / 100 = 4,367,867 (4,379,000)
     
  • If you accelerate at 1g for 1 year (not accounting for relativistic effects), you will be traveling within 97% of the speed of light
    299 792 458 / (9.80665 * 60 * 60 * 24 * 365.242374) = 0.968735306
     
  • The position of a full moon mirrors the position of the Sun 6 months away.

  • The Moon is 400 times smaller than the Sun, and it's elliptical orbit is 400 times closer to the Earth than the Sun on average - which provides perfect total solar eclipses that enable the Sun's corona to be observed with the naked eye while the entire surface of the Sun is covered by the Moon.



I hope you have enjoyed this brief glimpse into the wonders of our nearest celestial companion.

'Till next time,

-Aubrey Falconer
 
 
 
Bonus Questions:
  1. What is "regolith"?
  2. Why are there two tides every day, instead of just one?
  3. What does the term "phase angle" refer to?
  4. Why do we always see the same side of the Moon?
  5. What is the difference between "lunar" and "solar" calendar systems?

» Reply to Comment
Re: Three Intriguing Lunar Inquiries
2 weeks - 32,767v
Posted 2010/02/17 - 19:32 GMT
Fascinating article Aubrey! Well written, informative, and interesting!
Thanks for sharing this information, my mind was blown away!
» Reply to Comment
Re: Three Intriguing Lunar Inquiries
14 hours - 2,434v
Posted 2010/02/19 - 3:03 GMT
That is pretty awesome!
» Reply to Comment
Re: Three Intriguing Lunar Inquiries
1 hour - 113v
Posted 2010/02/28 - 0:35 GMT
Fascinating! I enjoyed it very much! Thank you. The pictures are amazing, as well! Who could doubt that there is a God?


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