The Case for a Creator - Lee Strobel [95]
“Another way it’s anomalous is that the sun’s orbit is more nearly circular in the galaxy than most other stars of its age. That helps by keeping us away from the galaxy’s dangerous spiral arms. If the sun’s orbit were more eccentric, we could be exposed to the kind of galactic dangers I mentioned earlier, such as explosions of supernovae.”
I realized after Gonzalez’s comments that I would never look at the bejeweled night sky as I had in the past. I used to see stars as being fungible, which is a legal term meaning one is just as good as the other. But now I understood why the vast majority of stars would be automatically ruled out as being capable of supporting life-bearing planets.
It would take a star with the highly unusual properties of our sun—the right mass, the right light, the right composition, the right distance, the right orbit, the right galaxy, the right location—to nurture living organisms on a circling planet. That makes our sun, and our planet, rare indeed.
As much as I have been fascinated by the sun, I’ve also frequently stared in wonder at the other dominant celestial body in our sky—the moon. Curious to find out whether this barren, rocky satellite contributes anything to its host planet—other than inspiration for poets and other romantics—I proceeded to turn our discussion toward lunar issues.
OUR LIFE-SUPPORTING MOON
Centuries ago, the dark patches on the moon—low-lying areas that had been flooded with basaltic lava—were thought to be oceans that provided life-giving water to its unseen population. They were called maria, Latin for “seas.” 34 The name has stuck; to this day, for example, we still refer to Mare Tranquilitatis, or the Sea of Tranquility.
Johannes Kepler, the seventeenth-century astronomer who fanned the flames of the Copernican Revolution, gazed at the moon and believed he discerned caves that were populated by moon people. He even wrote a book in which he fantasized about what their lives might be like. 35 A century later, William Herschel, who gained fame by discovering Uranus, thought he made out cities, highways, and pyramids on the lunar landscape.” 36
As scientific knowledge grew, dreams of finding lunar civilizations dissipated. Everyone came to agree that the moon cannot support life. Yet surprising discoveries in recent years have shown the opposite to be true: the moon really does support life—ours! Scientific evidence confirms how this parched, airless satellite actually contributes in unexpected ways to creating a lush and stable environment a quarter of a million miles away on Earth.
When I asked Gonzalez about how the moon helps support life on our planet, the first thing he brought up was a discovery that only dates back to 1993.
“There was a remarkable finding that the moon actually stabilizes the tilt of the Earth’s axis,” he said. “The tilt is responsible for our seasons. During the summer, in the northern hemisphere the north pole axis is pointed more toward the sun. Six months later, when the Earth is on the other side of the sun, then the south pole is more pointed toward the sun. With the Earth’s tilt at 23.5 degrees, this gives us very mild seasons. So in a very real way, the stability of our climate is attributable to the moon.”
“What would happen,” I asked, “if the moon were not there?”
“Then our tilt could swing wildly over a large range, resulting in major temperature swings. If our tilt were more like ninety degrees, the north pole would be exposed to the sun for six months while the south pole would be in darkness, then vice-versa. Instead, it varies by only about one and a half degrees—just a tiny variation, because the gravity from the moon’s orbit keeps it stabilized.
“The moon’s large size compared to its host planet is unique in the inner solar system,” he continued. “Mercury and Venus have no moons. Mars has two tiny moons—probably captured asteroids—and they don’t do anything to stabilize the axis of Mars. Its axis is pretty close to Earth’s right now, but that’s only by coincidence. It actually