No Ordinary Moon
Nearly every night a truly remarkable object greets us—the moon. It presents the same face, yet
changes subtly on its monthly orbit around our planet. Because the moon’s
journey is so regular and repetitious, we easily take it for granted. But it’s
truly a wonder. The more we learn about other satellites, the more unique it
appears to be.
We know from Scripture that God gave the moon a special place in his plan
for the universe. He ordained the moon and other heavenly bodies to help us
keep time (Genesis 1:14). Did you know that our monthly calendar, which we
order our lives by, came from the moon’s orbit (not the sun’s)?
God also made the moon to provide light on the earth at
night (Genesis 1:15, 17). Imagine the drabness of a moonless sky every night of the year!
Despite the central place God gave the moon in his account of the universe’s
origin, secular astronomers try to minimize its significance. If evolution
is commonplace, then they believe nothing about the earth should be
unique, including its satellite.
With ever-improving techniques to study our solar system and other stars,
evolutionary astronomers are hoping to find earth-like planets and moon-like
satellites all over the place. How’s their quest going?
Just Another Satellite in our Solar System?
With the invention of the telescope four centuries ago,
the moon appeared to lose some of its luster. In 1610 Galileo
discovered four satellites orbiting Jupiter, and we now know
that two are much larger than our own. Saturn has an even
larger satellite, Titan—the largest in the solar system, even
bigger than Mercury. (Neptune’s Triton is also larger than
So the moon isn’t the biggest satellite. Natural satellites
aren’t even rare in the solar system. Currently the known
number is 175 and growing. Is there any sense in which the
moon is special?
Let’s look at some other stats. The massive outer planets
have numerous satellites (not just one). What about the
inner, terrestrial planets? Mars is orbited by two small satellites,
but Mercury and Venus have none. So the earth is the
only planet in the solar system with a single natural satellite.
What about size comparisons? The earth is the only terrestrial
planet with a relatively large satellite. None of the
outer planets have a satellite so close to its own size, either.
While it’s true that the moon is smaller than the earth,
the other planets’ satellites are many thousands of times
smaller than their respective planets.
This close match in size produces
another unique attribute of our earth-moon
system—tides. No other planets
have such high tides. But then no
other planets have oceans and need
tides to sustain life.
The Moon’s Unique Orbit
The moon has another unique feature
that is often overlooked but just
as important—its orbit around the sun.
To appreciate its specialness requires
Generally speaking, smaller satellites
move in an elliptical orbit around
their planets, a sort of stretched-out
circle. However, all the major satellites,
including the moon, have nearly circular orbits around
their planets. As each satellite orbits the planet, it is also
rotating around its own axis. Most satellites, including our
moon, orbit their planets in the same direction that the
planets rotate on their axes (with one exception among the
major satellites, Neptune’s Triton).
Here’s what is interesting. Most major satellites orbit on
a plane that matches the planet’s rotation along its equator.
(Again, Triton is an exception.) Many minor satellites orbit
this way too, though some have extreme elliptical orbits
with odd paths around their planet—some like Triton even
revolve backward with respect to their planet’s rotation. The
moon doesn’t fit any of these categories.
However, the moon orbits on a plane that nearly matches
the plane of the earth’s revolution around the sun (see illustration
below). No other satellite orbits in the same plane
that its planet revolves around the sun. Not one out of 175.
A Unique Orbit
This fact has a profound effect on the earth, suggesting
design. The earth needs to maintain its tilt in order to have
the changing seasons and keep temperatures fairly balanced
around the globe. But other bodies in the solar system
exert a small gravitational pull that slowly tends to tweak
the earth’s axial tilt. Left unchecked, the earth’s tilt would
Our moon’s unique size and orbit stabilizes the earth’s tilt. This is the only
planet where this is possible, but since life appears unique to earth, this is the only planet where it matters.
At one extreme, this change in the earth’s tilt would result
in no seasons. On the other extreme, seasonal changes
would be much more drastic than they are today, with much
of the earth shifting from the boiling tropics in one season
to the Antarctic’s frigid, sunless winters. Obviously, this
would have disastrous consequences for living things.
But this does not happen because of the moon’s unique
large size compared to earth and its unique orbit in the same
plane that the earth orbits the sun. These two factors combine
to allow the moon to stabilize the earth’s tilt to within
two degrees. Both factors must be in play for this stabilizing
force to work. This is the only planet where this is possible,
and since life appears unique to earth, this is the only planet
where it matters.
Big Is Relative
Where Did the Moon Come From?
The moon’s unique orbit provides a clue that it has a
unique origin. Secular scientists admit that it must have
been formed in a unique way, unlike any other satellite
in the solar system. But since they won’t credit the Bible’s
answer, they’re desperately looking for an alternative explanation,
no matter how bizarre.
Even before we sent men to the moon to collect samples,
astronomers knew that the moon has an unusual composition,
as well as an unusual orbit. By the 1960s, they had
developed three theories for the moon’s origin. While the
main incentive for the Apollo program was to win the space
race, they had scientific objectives as well. One was to settle
which theory of lunar origin was correct. The rock samples
proved that none were true.
How did the moon get here, then?
After the Apollo program, NASA planned two Voyager
probes to visit the outer planets and, along with other scientific goals,
examine their satellites to help figure out where our
moon came from. Despite everything they already knew
about the moon’s uniqueness and the surprises of the Apollo
mission, they still assumed that the moon must have an origin
scenario similar to other satellites in the solar system. So,
if scientists could figure out where the major satellites of other
planets came from, they could discover the moon’s origin.
Behind these theories is the evolutionary assumption that
the solar system formed 4.6 billion years ago when a cloud
of gas and dust contracted under its own gravity. Most of the
material supposedly fell to the center, eventually forming
the sun. Meanwhile, the remaining material flattened into a
disk, in which small particles began to come together. Over
time, these little particles collected into larger and larger
particles. Gravity attracted more particles until some grew
large enough to become planets.
So where did the satellites come from? They propose two
possibilities. Some particles that didn’t fall directly into
the planets could have orbited the planets as they formed,
eventually assembling themselves into planetary satellites.
Other particles failed to become part of any planet. These
leftover pieces presumably became asteroids and comets.
Later (or so the theory goes), the planets captured some of
these asteroids to become satellites, usually with very elliptical
But neither of these scenarios fits our moon! The moon
doesn’t have a highly elliptical orbit, so it wasn’t captured.
But it also doesn’t fit the data for satellites which supposedly
formed in orbit at the same time as the planets. These satellites
should orbit around the planets’ equator, but the moon
doesn’t do that. Both these scenarios utterly fail.
As a result, theorists have attempted all sorts of special
cases to explain this unique satellite. The conventional thinking
for some time has been that another body about the size
of Mars impacted the earth shortly after it formed. This glancing
blow supposedly sprayed debris into orbit, from which the
moon coalesced. But even this unlikely explanation failed to
explain subtle differences in composition between the earth
and moon. To solve this problem scientists recently suggested
a series of large impacts from bodies with different material
composition, instead of a single impact.
Ironically, these evolutionary theories require a series of
exceptional events. Naturalistic astronomers assume nothing
is unusual about the earth and yearn to prove that. Yet
they can’t find a straightforward, simple theory for the origin
of the earth and its satellite. So, to explain the moon’s
unique orbit, they devise increasingly extraordinary explanations,
which aren’t proven or supported by data from the
rest of the solar system.
How many special circumstances is a theory allowed
before it collapses? How many coincidences must be strung
together before a reasonable scientist acknowledges that
design is a better explanation than happenstance?
The Biblical Worldview
We know from Genesis that God gave the moon (“the
lesser light”) unique functions from the very beginning of
time. The moon, along with the sun (“the greater light”), has
specific purposes to assist mankind in his role to honor and
serve the Creator on earth. All the rest of the universe falls
under “the stars also” phrase of Genesis 1:16, which relegates
the other satellites to a secondary status (at least in
This wording strongly implies that God made the moon
with special purposes unique in creation. It is not surprising
that He made the moon with so many special properties that
scientists have come to appreciate, including the ones summarized
in this article. The moon’s unique orbit surely is one
of these attributes that testify to the moon’s special status,
in a language which anyone can understand.
The heavens declare the glory of God, and the sky above” (Psalm 19:1–3).
proclaims his handiwork. Day to day pours out speech, and
night to night reveals knowledge. There is no speech, nor are
there words, whose voice is not heard
of physics and astronomy at the University of South Carolina Lancaster. He has written
numerous articles in astronomical journals, and he is the author of Universe by Design.