How many planets are there in our solar system? Nine? Eight? Twelve? Hundreds?
I know many will insist there are nine, with Pluto as the ninth planet, but remember that in 2006 Pluto was reclassified as a dwarf planet, and that left us with eight official planets.
Keep in mind, however, that the definition of the word “planet” is still somewhat unsettled, so even that answer may not be correct.
It wasn’t always that way, however. A couple of hundred years ago, every astronomer and schoolchild knew the answer.
There were six planets: Mercury, Venus, Earth, Mars, Jupiter and Saturn, five of which wandered the starry heaven from night to night.
And those are the only planets known since the dawn of time.
That’s why in 1781 the world was stunned when musical composer and amateur astronomer William Herschel found a seventh world.
It was soon named Uranus (pronounced YOU-rah-nus) in honor of Ouranos, the father of the Titans and grandfather of Jupiter in Greek mythology.
What’s curious about Uranus is that no one had found it earlier, as the planet is sometimes bright enough to see with the unaided eye. And right now is just one of those times.
Uranus reaches its opposition — the point in its orbit where it lies closest to Earth — on Saturday, Nov. 16, and for the next week or so will rise in the east shortly after sunset.
Finding Uranus takes some patience, but it’s not too tough since it now appears just south of the Pleiades (aka Seven Sisters), the shimmering star cluster you’ll easily spot low in the eastern sky after dark.
To search for the planet, first use binoculars to find the Pleiades. This in itself is worth enjoying, as its bluish-white stars sparkle like diamonds on black velvet.
If you can tear yourself away from this sight, swing your binoculars about one field of view to the right.
Identifying which “star” there is Uranus, though, might be a challenge. I suggest comparing the star pattern you see in your binoculars with that in the illustration provided, and you might be able to figure out which one is the planet.
Uranus has a slight bluish-green tint, and once you find it, try searching for it with your eyes alone. If you have excellent vision and a clear, very dark rural sky far from city light pollution, you may be surprised by how easy this is!
What puzzles me is that, if we can see Uranus with the unaided eye, why hadn’t the ancients found it?
And if they had, how might that have changed our culture? After all, the five visible planets (along with the sun and moon) lent importance to the number “seven,” and we see it everywhere.
There are seven rungs of perfection, seven emblems of the Buddha, the seven gates of Thebes, seven wonders; even seven days of the week!
So it’s only natural to wonder how things might be different if the ancients knew of eight — instead of seven — significant bodies that traveled across the heavens. It’s really quite surprising that they didn’t.
Just a little mystery to ponder while stargazing this week!
