Hundreds of moons, planets and other bodies in the Solar System, and only ours — Earth and the Moon — have perfect solar eclipses. Astronomers have long noted this strange phenomenon, and the unlikely parameters that cause it. Not only that, but they happen to occur in a time in Earth’s history where they can be observed. Astronomer John Gribben writes:
Just now the Moon is about 400 times smaller than the Sun, but the Sun is 400 times farther away than the Moon, so that they look the same size on the sky. At the present moment of cosmic time, during an eclipse, the disc of the Moon almost exactly covers the disc of the Sun. In the past the Moon would have looked much bigger and would have completely obscured the Sun during eclipses; in the future, the Moon will look much smaller from Earth and a ring of sunlight will be visible even during an eclipse. Nobody has been able to think of a reason why intelligent beings capable of noticing this oddity should have evolved on Earth just at the time that the coincidence was there to be noticed. It worries me, but most people seem to accept it as just one of those things.
Even if we brush this off as coincidence, as some have tried to do, there is another layer to this. Many of the interconnected factors that allow the eclipse to occur, also allow life to exist on Earth. Continue reading