There’s some discussion going on at the moment about Sedna, specifically about whether or not it should be called a planet. Oddly, I seem to be the only person who thinks it should be called a planet, but it shouldn’t be called Sedna. In the words of Lisa Simpson, "That’s not Latin!" Anyway, some of this discussion happened at slashdot, and a particular subthread led to an interesting assertion: that children can be made to want to learn by demonstrating that there’s something interesting to be learned.
An easy example is the degree of interest in dinosaurs after the release of Jurassic Park. Kids saw that instead of boring ‘…168 million years ago…’ and ‘…fish crawled onto land…’, they could learn about huge, terrifying monsters that ran and jumped and did exciting and gory things to each other for millenia. They could see what was so cool about these things.
Now think about what you learned about astronomy in school. You most likely know a mnemonic to remember the nine major planets. You may know they have near-circular orbits; that Earth is third from the centre and the only one to sustain life. And there, for most people, it ends, with that horrible ‘only one’ statement making it seem that none of the other miriad objects in the universe holds anything of interest. Well here’s the good stuff, off the top of my head, about the first four planets:
- Mercury
- Smaller than Ganymede, one of the moons of Jupiter. Temperature goes from -170°C at night to 250°C during the day. Its day is nearly ten times as bright as Earth’s. At certain times, if you were to stand on the surface of Mercury at the right point, you could watch the sun rise in the sky, stop, then go back and set in the East. It would then rise again and continue on its way.
- Venus
- The weird uncle of the solar system. Women are from Venus, because it’s completely bonkers. Almost every body in the solar system (indeed almost every body in the galaxy) rotates counterclockwise when viewed from above Earth’s North pole. Every planet, asteroid, moon and comet orbits and rotates in that direction. But not Venus. It spins backwards. Venus is hotter than Mercury even though it’s further from the sun, because it has a huge carbon-dioxide atmosphere that would crush, dissolve and melt a metal can with its strong heat, pressure and acidity. Though Earth is the only planet on which people could survive, I can never shake the feeling that venus is somehow less hospitable than the rest. It’s just mean
- Earth
- Think of how much you know. All the people, places, history, geography. Think of all the cultures in all of the world. Think of what came before them; cave men, early hominids, ancient mammals, dinosaurs, ambitious fish, bacteria, a single self-replicator that became the common ancestor to everything that ever lived or will live. That’s all Earth. Our moon is made of Earth; that is, at some time in the past it was torn off and left hanging in space destined to protect our developing world from asteroids that would have spelled doom for our ancestors. Just think that almost everyone, ever, has seen the moon as you can see it every night.
- Mars
- You can’t have failed to hear about Mars recently. It has an apetite for probes. It also has two moons, Phobos and Deimos. Phobos is so close to Mars that it has to orbit incredibly fast just to stay up, but its orbit is slowing down. Some time in the future Phobos will crash into Mars with a force far in excess of anything we could create with an atomic bomb. Deimos is so small that you could literally jump off of its surface; you might be lucky enough to land back on it in a day or so.
I could go on with Jupiter’s many moons, including my personal bet for Hell, Callisto; Saturn’s rings and missing spokes; Uranus’s crazy axis; Neptune’s death-sentenced moon Triton; and the peculiar double planet Pluto/Charon. Even an encyclopaedia introduction to the solar system describes a huge array of weird and alien environments. For people who are taken in by science-fiction sets with odd-coloured trees, what would it be like to see (not to mention smell) a moon with solid methane cliffs?
Now as for white dwarfs, neutron stars, pulsars, black holes, quasars and supernovae…