Here are some factoids you can use at your next Moon-observing party.
1. Our Moon is the biggest satellite in the solar system relative to the planet it orbits.
It’s more than one-quarter the Earth’s diameter, which, by some definitions, makes ours a double-planet system. And of the four rocky worlds nearest the Sun, Earth is the only one with a real moon. Mercury and Venus orbit solo, while Mars is accompanied by two tiny satellites that are most likely captured asteroids.
2. Driving to the Moon would take a long, long time.
While Apollo astronauts managed to rocket into lunar orbit in only three days, driving there in your car would take more than five months. And even then, you’d have to go 100 kilometres per hour without stopping for gas or bathroom breaks. A trip to the Moon would probably void your vehicle’s warrantee too.
3. There’s no such thing as the “dark side” of the Moon.
Far be it for me to contradict a popular album by a popular band, but both sides of the Moon receive exactly the same amount of sunlight. The lunar far side is simply the hemisphere hidden from earthly view, but of course, it receives as much daylight as the side we can see. Even Walter Cronkite, the iconic television anchorman of the Apollo program, got it wrong several times.
4. No one has walked on the Moon since December 1972.
That’s right. Not since bell bottom trousers were fashionable and teenagers were discovering the modest thrills of a video game called Pong has anyone set foot on luna firma. Yet whenever I tell young kids this, they find it hard to believe, because space exploration seems so routine to them. Sometimes even I have a hard time believing it’s been that long.
5. The dinosaurs looked up at the same Moon as we do.
When dinosaurs roamed the Earth 65 million years ago, the familiar face of the Moon was already complete. All the main craters, maria and other surface features are much older than humanity.
6. The “silvery” Moon is actually dark grey.
The lunar surface is about as bright as asphalt under the midday Sun. So why does it look so bright in the sky? Call it an extreme contrast effect: Set against the darkness of the night sky, the Moon only seems superbright. When you spot the Moon during daylight hours, you know how pale it really is.
7. The rising Moon isn’t bigger than at any other time.
Anyone who has seen a full Moon hovering above a distant horizon has witnessed the “Moon illusion” at work. Not convinced? Try this experiment next time. Cover the lunar disc with the eraser end of a pencil held at arm’s length. Then try again when it’s overhead. You’ll find that you can erase the Moon equally well in both situations.
8. The best time to view the Moon is not when it’s full.
Friends who know about your interest in astronomy have probably asked you at one time or another whether you were “out last night looking at the full Moon.” As impressive as it is to the unaided eye, the full Moon isn’t nearly as interesting for telescope users as are the other phases because when the lunar surface is fully lit, there are no shadows, which make features stand out.
9. In total, we have gathered only about 950 pounds of Moon rocks.
Most of these were collected by the Apollo astronauts, and some are from meteorites that originated on the Moon. By comparison, our stockpile of diamonds grows each year by 60 times this amount.
10. We may owe our lives to the Moon — literally.
If one current theory is correct, none of us would be here if Earth hadn’t had a big moon. The complex interactions between the stability of the Earth’s rotation and axial tilt generated by the tides of the Moon ultimately led to the rich diversity of life we have on this planet. Without the Moon’s tidal influence, conditions may have been too erratic and hostile for complex life to emerge. And “complex life” includes us.