All right, this is for real. I actually heard someone say on the radio that he was afraid the earth will tip over. Granted, it was someone calling into Coast to Coast AM, but the mere mention of it sent chills up my teacherly spine.
Here’s the gist of what he said. As we approach the summer solstice (June 22 here in the N hemisphere), the sun moves higher and higher in the sky. As we approach the winter solstice (Dec. 21), the sun moves lower in the sky. The caller asked if there was ever a possibility that the earth might just keep going and tip over. The guys on the radio program I think we thinking the same thing as I was — this guy is clueless — but they managed to set him straight without deflating his ego.
It took me awhile to figure out why he was worried, though. Here it is. His concept of the (apparent) motion of the sun northward and southward during the year was that the earth was slowly rocking back and forth. He was afraid that the earth would rock too far, putting the sun on the horizon or worse yet turning the world upside down!
Now. the reasons for the seasons and the movement of the sun seems to be one of those topics that otherwise intelligent people never seem to get straight. Maybe we don’t do a good job of teaching it in school (assuming we do). It’s pretty hard for some folks to adopt a gods-eye view of the solar system to see how things work, too. Without a teacher demonstrating the arrangement of earth and sun with props, schoolkids will never get the idea straight just from reading textbooks (if they ever read them).
Well, the CtoCAM hosts corrected one aspect of the caller’s confusion. They stated, correctly, that he was perhaps thinking of the reversal of the earth’s magnetic field, which has occurred many times in the planet’s history. They did allow for the possibility, mind you, that the world could “flip over.”
Immanuel Velikovsky notwithstanding, it is next to impossible that the earth could flip over. It would take a collision with an immense celestial body to tip the earth over, which in the process would kill everyone in the process. The earth has a lot of mass and it’s spinning pretty fast (about 1000 mph at the equator), so it is like a colossal gyroscope. And gyros, as long as they are spinning, don’t tip over easily.
It has happened to other planets, it seems. Uranus, that cold bluish gas giant way out there, rotates “sideways” — its poles are almost level with the plane of its orbit. Since all the other major planets (Pluto excepted) have their poles roughly perpendicular to the planes of their orbits, something major has to happened to Uranus long, long ago.
I won’t go into the details of the sun’s seasonal movement here. I may add an explanation in a separate area of the site later on. Meanwhile, use Google if you’re unclear.