Reasons to Believe

Confirming the Moon's Vital Role

These highly fine-tuned features form one of the cornerstones of the evidence for a supernatural, super-intelligent Creator

Back in 1993, a research team led by French astronomer Jacques Laskar proved analytically that the tilt of Earth’s rotation axis is stabilized over long time periods thanks to Earth being orbited by a single moon whose mass is a substantial fraction of Earth’s.1 (See here and here.) Laskar’s team showed that with the Moon Earth’s rotation axis tilt varies over many millions of years between 22.0 and 24.6 degrees. Without the Moon, Earth’s rotation axis tilt would vary between 0 and 85 degrees.

Variations in Earth’s rotation axis tilt of much more than a couple of degrees would generate climate changes catastrophic for advanced life. Consequently, the Moon’s amazingly unique features (for example, the Moon-Earth mass ratio is fifty times greater than for any other known moon-planet system) are crucial for the existence of advanced life. These highly fine-tuned features form one of the cornerstones of the evidence for a supernatural, super-intelligent Creator.

In the context of evidence for design, astronomers, for some time, have desired a more rigorous confirmation of the Laskar team’s research results. Now, such a confirmation has arrived.2 This new study uses realistic planetary orbits and takes into account both solar and planetary torques exerted on the Moon and the Earth. The calculations extend from two billion years in the past to two billion years into the future.

The new analysis finds that short-term variations in the tilt of a moonless Earth’s rotation axis are somewhat less than what Laskar’s team calculated. The long-term variations (timescale in excess of 100 million years) are just as prominent. Therefore, this particular evidence for the design of the Earth-Moon system for the specific benefit of advanced life has now been more rigorously established.

Subjects: Earth/Moon Design

Dr. Hugh Ross

Reasons to Believe emerged from my passion to research, develop, and proclaim the most powerful new reasons to believe in Christ as Creator, Lord, and Savior and to use those new reasons to reach people for Christ. Read more about Dr. Hugh Ross.


  1. Jacques Laskar and P. Robutel, “The Chaotic Obliquity of the Planets,” Nature 361 (February 18, 1993): 608-12; Jacques Laskar, F. Joutel, and P. Robutel, “Stabilization of the Earth’s Obliquity by the Moon,” Nature 361 (February 18, 1993): 615-17.

  2. Jason Barnes, Jack J. Lissauer, and John E. Chambers, “Long-Term Obliquity Evolution of Reimagined Moonless Earths,” Astrobiology 8 (April 2008): 373.