Ignorance Friday - 2
Time once again to remember that what we think we know, we probably don’t. The subjects at hand: orbits and moons and light. Ready?
1. Does the earth go around the moon or vice versa?
Nope, not moon orbiting earth. Try again.
Nope, not earth orbiting moon. Try again.
That’s right. They actually go around each other. There’s this invisible pivot point approximately 1000 miles beneath the surface of the earth. In fact, the earth actually makes three different rotations: around the sun, around its own axis, and around this pivot point.
2. How many moons does the earth have?
I know, I always thought just one. Nope. It’s actually 7, if you count the six other near earth asteroids which follow the earth around the sun. Not strictly moons, you say? Well, consider their travel around the sun is approximately one year, and sometimes these come near enough to exert a slight gravitational influence on mother earth.
3. How fast does light travel?
If I remember my physics correctly, it’s a constant 186,282 feet per second. Would you agree?
Well, for starters, it isn’t constant. Only in a perfect vacuum does light reach its maximum speed. Then, it depends on what it travels through as to how fast it moves. Through a diamond its about 80,000 miles per second. Through sodium at -272 degrees Celsius: 38 mph. That was the slowest ever recorded, until recently. You see, there’s this team at Harvard that’s just not satisfied with riding light as fast as their Moped. Apparently they have been able to bring light to a complete standstill. How? By shining it into a Bose-Einstein condensate (whatever that is) of the element rubidium.
3a. Extra credit: What’s the color of light?
OK, you know it isn’t a color, it’s the absence of color. But consider this: You can’t see light. It’s invisible. You can only see what it interacts with. Otherwise, it would be something akin to seeing fog, where everything in front of you is obscured. (Which is so appropriate for this site’s theme, don’t you think?)
3b. Extra Extra credit: What’s the color of darkness?
I don’t know, since it isn’t there and I can’t see through it.