Wednesday, August 26, 2015

Moon Musings

Isaiah refers to bodies in our Solar System when he quotes, “…Thus says the Lord, ‘Heaven is My throne and the earth is My footstool…For My hand made all these things, thus all these things came into being’ declares the Lord…” (Isaiah 66:1-2 NAS). In several Bible references the Moon offers praise to the Creator. It is a faithful witness to God’s glory, exuding splendor and supplying the Earth with light.

Of these visible astronomical objects in our sky—the Sun, planets, stars, and the Moon—the Moon inspires a different order of wonder. The 93 million mile distant Sun sustains all earth life with its light and heat on a daily basis but ironically, it is too bright and dangerous to observe with the unaided eye except briefly at sunrise and sunset. Planets many millions of miles distant shine with reflected light in the darkened sky, slowly changing their positions over many months, revolving independently against the field of stars. They are the most numerous of celestial representatives catalogued in our post. Stars glow remotely with their own light in subdued subtlety. Earth’s Moon, however, is our celestial next door neighbor. Shining with reflected light, it is only 238,000 mies away and fascinates us with its close relationship to our planet.

We caution against claiming that Scripture teaches modern scientific truth. This does not make the Bible unreliable in any sense. Scripture’s commentary on astronomical phenomena relies on ancient observations made when Scripture was penned. References to astronomical bodies speak of their origin as the handiwork of the Creator and devotional spiritual object lessons. We find several dozen biblical references to the moon and perhaps three times that many concerning the sun.

Explicit references to the eight named moon phases and stages as we know them today are not found in the Bible. Neither are reports of the revolution of the moon around Earth found in holy writings. The closest we come is frequent Old Testament passages mentioning new moons and several verses describing the full moon. The first sighting of a new moon is the beginning of a new month. Often the new moon was a signal to begin festivals or feast days of the Jewish tradition. The new moon was not an astronomical event of closest alignment of sun, moon, and earth. Rather, it was proclaimed about two days later at the first visual appearance of a thin crescent of illumination.

In our time we note an increase in detailed knowledge of our lunar companion. Examples: The Moon’s diameter is 27% of Earth’s diameter, and the Moon’s mass is 1.23% of Earth’s mass. This is about 1/80 of the mass of Earth. We have noted the stabilizing effect of the Moon in relation to our axial tilt. Our lunar companion is vital for life on Planet Earth. Without a stable axis of rotation Earth life as we know it would be impossible. Earth’s axis tilts at 23.5º from the plane of the Earth’s orbit.

Our planet experiences tides from the Moon. Ocean waters facing the Moon are pulled gravitationally toward it. Opposite the Moon the solid earth is pulled slightly toward the Moon causing an inertial bulge of water on the opposite side of the Earth. The water lags slightly behind the solid Earth. Different configurations of continental land masses cause funneling effects resulting in varying tidal depths from one place to another. The same face of the Moon is always directed toward Earth as the bodies are gravitationally “locked.”

The beautiful phases and stages—new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, last quarter, and waning crescent—occur in sequence every 29.5 days. This is termed a synodic month, defined by two successive conjunctions of the Moon and the Sun. The moon revolves once every 27.3 days, a sidereal month defined according to the stars. Different phases and stages are caused by different angles of lighting depending on varying configurations of Earth, Moon, and Sun over the synodic month.

We close by briefly discussing the current widely accepted theory of the Moon’s formation. Very early in the history of the young Solar System a giant impactor dubbed Theia, possibly as large as Mars, crashed indirectly into Earth. Much debris from the impact splayed about and some coalesced into what later became the Moon. Apollo Moon explorations have determined Moon rocks to be slightly younger than Earth, consistent with the impactor theory. Many origins theorists have presented substantial evidence and confidence in the impactor theory of Moon formation. We present these ideas as a viable hypothesis, not as fact.

In modern times we are gifted with ability to correlate discoveries in order to acquire a fuller picture of truth concerning the Moon. Astronomy offers plentiful opportunities to give glory to the God of order and purpose. As students we may focus on fascinating details relative to the Moon as we have in this post, or on the store of knowledge we have accumulated on a multitude of other astronomy topics.