Astronomy in a parallel universe [View all]

[Lionel Mandrake]

Parallel universes, from branes to the many-worlds interpretation of quantum mechanics, are popular among theoretical physicists. This means that "what-if" scenarios in history are not entirely contrary to fact; they merely contradict the facts in our particular universe.

Consider the following example. In the late sixteenth century, Tycho Brahe observed a certain sixth-magnitude star. Continuing to observe this star over several years, Tycho made the startling discovery that it moved relative to the "fixed stars". Eureka, he had discovered a new planet! Since the discovery took place at his famous observatory Uraniborg, Tycho decided to call the planet "Uranus". Other astronomers were shocked at the news. Many of them couldn't see Uranus at all - they lacked the keen eyesight that Tycho was famous for. Some went so far as to deny the existence of Uranus, branding it a hoax. In time, other astronomers verified that Uranus was real, and the scholarly world came to accept its existence.

When the old king of Denmark died, Tycho had to confront a new, young monarch who was not interested in supporting astronomical research. Tycho was forced to look elsewhere for support, and he ended up at the court of Emperor Rudolph II in Prague. There he met a young astronomer named Kepler, who was also something of an exile. Kepler was not much of an observer, but he excelled at mathematical astronomy. Tycho gave Kepler the problem of computing the orbit of Mars. Out of this collaboration came Kepler's laws relating to elliptical planetary orbits.

In this universe, Kepler did not publish a book in 1600 containing the following figure:



As attractive as this explanation of the sizes of the planetary orbs was, it left no place for the planet Uranus. Kepler reluctantly decided that it was a false explanation, and he gave more attention to convincing Galileo and others that planetary orbits were indeed elliptical. As a result, the scientific revolution in this universe started earlier and went farther than in our universe.