How many planets does our solar system have? Eight? Twelve? Two hundred? With the definition of planet so newly restated, you're likely to get a debate among astronomers.
It wasn't always that way, however. Back in the good ol' days – about 225 years ago, for example – every astronomer and schoolchild knew the answer. There were six planets: Mercury, Venus, Earth, Mars, Jupiter and Saturn. And six planets were all that had ever been known to humans since the dawn of time.
That's why, in 1781, the world was stunned when musical composer and amateur astronomer William Herschel announced his discovery of a seventh planet. In an attempt to impress King George III and to get some money to do astronomy, Herschel suggested they name the new world Georgium Sidus (George's Star) after the king.
Having a planet named George made as little sense then as it does now, so the planet was ultimately named after the father of the Titans and grandfather of Jupiter in classic mythology: Uranus. Incidentally it was then (and still is) pronounced YOU-rah-nus.
What's most intriguing about Uranus is that it wasn't found earlier – for the planet can sometimes be seen with the naked eye. In fact, right now is one of those times and, if you've never seen our seventh planet, this is the time to begin your search.
Uranus reached its opposition – the point in its orbit where it lies closest to Earth – Tuesday. It is now rising around sunset and lies “only” 1.77 billion miles from Earth.
Finding Uranus takes some patience, but it's certainly not difficult. When the moon leaves the evening sky at the end of this week, go outdoors just after dark and find the constellation Aquarius, the Water Bearer, low in the east. Now aim binoculars toward the star Lambda Aquarii just below the constellation's center and you should have little trouble spotting Uranus about one degree to its lower left – slightly more faint, but with a distinctly bluish-green tinge.
Once you know exactly which dot of light is Uranus, you might even be able to spot it with your eyes alone – but only if you have excellent vision and a clear, dark sky far from city light pollution.
© Copley News Service
