Our colleague’s concern is eminently practical: what would half a dozen moons circumnavigating the earth do to our ocean tides? (Full disclosure: she and I are fellow fishermen, and many of our younger colleagues are ardent surfers.) Would all those extra moons cause huge or unpredictable tides, perhaps even the dreaded tsunamis that occasionally bash our coasts and disrupt our marine trade and cruise ships?
An afternoon at our computers alleviated our concerns about this potential hazard. Together, we were able to devise several alternative models of multiple satellite orbits (MSOs) that would allay all irrational fears.
These models are built on the simple idea that not all the orbits of our “borrowed” moons would be either (1) equatorially aligned or (2) perfectly circular. For example, as many as three moons could orbit our planet around the two poles; at least two of them could follow an elliptical orbit. With attentive fine-tuning, any and all of our models could even provide us with completely placid oceans, in which all tides would vary as little as 3.678 centimeters on a calm day. Not that this would be desirable, we were quick to point out to our young surfer assistants; only that it would be possible.
Next morning I awoke with a dreadful premonition that there was still a major flaw in our theoretical work. Tides, I reasoned, are caused by the gravity that the present moon exerts on the earth we have grown accustomed to call home. Would not a plethora of moons be unsettling to our current arrangements—for example, apples that fall from trees to the ground instead of leaping skyward?
That afternoon my JPL colleague and I held an extensive consultation over the net. We concluded that it was theoretically possible to continue our budding joint project, under the auspices of the U. S. Government, the United Nations, the Pan-Arab League, the International Olympic Committee, the American Farm Bureau, and the Eagle Scouts. We became convinced that our initial goal of providing lunar energy to the world would not necessarily be compromised by the problem of gravity. In fact, it was possible for us to concoct a multi-moon model that would both preserve the advantages of present gravity and provide extra benefits of which we are presently deprived.
Let a pair of examples suffice. With the proper alignment of half a dozen tinfoil-coated moons, apples would fall more gingerly to earth, thus avoiding bruises; and world records would be set in practically every Olympic event. (The major exception would be in downhill skiing, a sport that would have to change its emphasis from speed to grace, thus freeing the skier from the fear of disastrous tumbles and careers shortened by knee and ankle injuries.)
We believe our initial plan will make the world a better place in which to ski.