The Stars Are Right

Many evolutionary biologists believe that there would never have been life on Earth if not for the moon. Not only does its orbit have a noticeable (and unexplained) effect on various physiological cycles, some researchers have suggested that the tides helped early animals move from the ocean onto land.

On a related note, modern analysis of gravitational fields in the solar system has shown that every planet and moon does in fact have a noticeable effect on every other planet and moon. Jupiter's gravitational impact is the largest, simply because it's the largest planet in the solar system. It's mostly made of gases like hydrogen, and astronomers have estimated that if it were slightly heavier (slightly by cosmic standards, that is), it would have reached the point where hydrogen could spontaneously fuse in its core - that is, it would have been another star. It's not clear whether that would have made Earth come out like Tatooine, though.

Our solar system is actually in the slight minority in that it only has one sun. Modern telescope observations have found that two or more is actually very common. In fact, many of the nearest star systems to Earth have three or more, including Alpha Centauri and Sirius.

Sirius, incidentally, was also one of the most important stars in ancient Egyptian mythology. It was associated with the god Osiris, the ruler of the underworld, who was said to have been the first being to be mummified. Interestingly, there is a shaft in the Great Pyramid at Giza which points directly at Sirius at certain times of the year. Not only does that involve a degree of precision engineering that we were only able to replicate in recent history, we don't know exactly what this symbolized to the Egyptians. Some people have speculated that it was a reference to resurrection or to the journey to the underworld, but in the absence of more explicit records from their time, your guess is as good as anyone's.

And we'll end with another story that many of you are probably familiar with: the Star of Bethlehem. The story is widely known in a form where the star literally leads the Wise Men to Bethlehem, which has prompted speculations of meteors, supernovae, and even more unusual phenomena. Recently, though, another theory has emerged which suggests that it was partially symbolic, and referred to an unusual conjunction involving Saturn, a planet which was associated with kingship and with the Jews specifically.