Moon Inching Away from an Old Earth

How Old Is Our Moon?

The Bible says God made the moon
on Day Four of Creation Week, and
the Bible’s genealogies reveal that this
happened roughly 6,000 years ago.
But that’s not the story we hear today.
Most science museums, websites, TV
shows, and textbooks claim the moon
formed by natural processes about 4.5
billion years ago. How do we resolve
such vast differences?

God’s Word is true in everything it
claims (Psalm 119:160). Jesus Christ,
the Son of God and Creator of the universe,
affirmed this (John 17:17). And
if His Word is true, we would expect
to find abundant scientific evidence to
support His claims.

We can calculate
the maximum
possible amount of
time the moon has
been orbiting the
earth—and it’s not
4.5 billion years.

Our moon has many age indicators
that support the Bible’s teaching that
creation happened thousands, not billions,
of years ago. One of the more
interesting is an effect of gravity called
lunar recession. Ever so slowly, the
moon is slipping away from the earth.
By measuring this rate, we can calculate
the maximum possible amount of
time the moon has been orbiting the
earth—and it’s not 4.5 billion years.

For decades, creationists have cited
this phenomenon as powerful evidence
in favor of the Bible’s history. Secular
scientists, in contrast, have tried to
find a way to save their idea that the
moon is extremely old. How well do
their rescuing devices stand up?

Lunar Recession

First, let’s discuss why the moon is
moving away from earth. The moon’s
gravity causes the earth’s ocean water
to bulge toward the moon. As the earth
rotates, parts of its surface move in
and out of the region of oceanic bulging.
(This makes local sea levels rise
and fall in tides.) However, as the
earth rotates under the bulge, friction
drags the bulge forward. This bulge
exerts its own gravitational effect on
the moon and accelerates it in its orbit,
causing it to move away from earth
over time.

Although it’s been known for a long
time that the moon should be receding
from our planet, the Apollo lunar program
of the 1960s and 1970s allowed
scientists to measure this process with
great precision. Over the last 40 years
or so, the moon’s average distance has
increased by roughly 1.5 inches (3.8 cm)
per year.

This might seem like obscure scientific
data, but it’s very important. This
measurement allows us to calculate
a maximum age for the earth-moon
system.

A Lunar Clock

If the moon is steadily receding from
the earth, then in the past, it was closer.
Based on today’s rate of recession, the
moon would have been touching the
earth about 1.5 billion years ago.

Of course, this doesn’t mean that the
moon was ever that close. It’s just the
logical limit to the physical process we
observe today. We can use this limit as
a sort of clock. According to this clock,
the earth-moon system cannot be more
than 1.5 billion years old.

Here’s an important point about this
calculation. It does not reveal the precise
age of the earth-moon system. It
merely tells us the maximum age.

The biblical age of the moon (about
6,000 years) fits this clock just fine. In
fact, the moon has not moved outward
very far—less than 1,000 feet (300
m)—since it was created.

But what doesn’t fit this clock is a
moon that’s over four billion years old.

Attempted Secular Rebuttals

Secular scientists have known for
over 50 years that a straightforward
analysis of the moon’s recession is a
“major problem” for their billions-of-years
interpretation of earth history.

Lunar recession is not merely a side
issue. This confirmed process poses
a major threat to evolutionary theories
overall, which require billions of
years. So it’s not surprising that evolutionists
have attacked its reliability
as a clock.

One common challenge, that the calculation
is wrong, still appears sometimes
on the Internet. But no serious
astronomer claims this. It goes something
like this: “A recession rate of 1.5
inches per year, over 4.5 billion years,
produces a total recession of less than
half the moon’s current distance. So
there’s no problem here after all.”

However, this assertion is both naïve
and false. It assumes that the recession
rate is linear and does not change over
time. In reality, mathematics dictates
that the recession rate would have
been much higher in the past, when the
moon was closer to the earth.

About the only way to get a slower
rate is to invoke different physical
conditions in the past. This is the preferred explanation among secular
scientists. They claim that today’s
recession rate is abnormally high.

To support this claim, they offer
multiple forms of evidence.

Geological Evidence

Sometimes
rock layers are found in repeating patterns
called rhythmites. Secular geologists
have identified certain rhythmite
formations as ancient tidal deposits.
These deposits are then used to “confirm”
that the moon’s rate of recession
was much lower in the past.

But this claim is hollow. Rhythmites
don’t necessarily tell us anything
about past tidal cycles, because
non-tidal flooding can create similar
deposits. (A glacial flood in Iceland
deposited about 50 feet [15 m] of rhythmites
in just two days back in 1996.)
Also, genuine tidal sediments have
distinctive patterns that these rhythmites
tend to lack. Rhythmites are
better explained as deposits laid down
quickly by a global Flood.

Paleontological evidence

Secular
scientists claim some types of fossils
(stromatolites, bivalves, corals, and the
like) have measurable growth patterns.
From these they calculate ancient day
lengths, tidal patterns, and so on.
But the same problems apply to
these as to rhythmites. The growth
pattern counts are often subjective
and can’t account for unique conditions
that may have existed in
the past (such as in the pre-Flood
world, which they are unwilling
to consider). So these secular calculations
are built on unverifiable
assumptions. They do not provide
independent proof that the lunar
recession rate was ever different.

Scientific modeling

Geophysicists
have done extensive modeling of the
earth-moon system. Some anti-creationist
websites claim these models
support much slower recession rates
in the past.

But that’s possible only by making
a set of assumptions. For example, to
reduce tidal friction (and thus reduce
the recession rate), these models
require the earth’s landmass to be
distributed much differently than it is
today. Some models have all the continents
combined into one supercontinent
at the equator or one of the poles.

Note that this is not how the earth
is today. Nor does it really match what
most secular geologists believe anyway,
that is, that there was a series
of supercontinents, which repeatedly
broke up and reformed over more than
three billion years. (Many creationists
believe something similar happened,
but within the one year of the global
Flood.) And somehow, this all had to
take place without significantly affecting
the moon’s recession rate until
very recently.

Also, oceanography research has
invalidated one of the key assumptions
of the secular models: that tidal friction
occurs only in shallow seas and continental
shelves. It turns out that friction
and dissipation of tidal energy occur in
the deep oceans, too. So these supercontinent
models have not solved the
recession problem after all.

An Admission That The Past Was Not As Today

This last point is very important.
Evolution is based on a uniformitarian
approach, that is, that “the present is
the key to the past.” Secular scientists
are adamant that we can base scientific
explanations only on present-day
observations. Accordingly, they presuppose
that the Bible is invalid as
an interpretive framework because it
describes events (such as a worldwide
Flood) that are not occurring today.

Yet in an attempt to solve their lunar
recession problem, secular thinkers
claim that the earth was much different
in the past than it is observed
to be today. If they can’t observe the
unique events that shaped our earth
and moon in the past, why won’t they
consider God’s record in the Bible? Science
is not the problem!

Lunar recession is not precise
enough to give us the actual age of
the earth-moon system (which is only
thousands of years). But the moon’s
recession does debunk many of the
foundational assumptions and billions-
of-years requirements of long-age
models.

The psalmist wrote, “The heavens
declare the glory of God” (Psalm 19:1).
As science progresses, we continue to
discover more ways in which the heavenly
bodies declare the glory of their
Creator.

Spike Psarris accepted Christ while serving as an engineer
in the US military space program. He now speaks on
creation, atheism, and Christian apologetics and is the
author/producer of the DVD series What You Aren’t Being
Told About Astronomy.