Mooning Around with Perfesser Friar
The Moon looks huge on the horizon, but it’s not, really. Regardless of where it is in the sky, it’s about the size of an aspirin tablet held out and arm’s length. (Try it if you don’t believe me).
If you consider the sky being 180 degrees from horizon-to-horizon, the Moon is about half a degree in diameter. This means you could fit 360 Full Moons across the sky, end-to-end.
If you want to compare the apparent size of the planets, it would take anywhere from about 35-60 Jupiters end-to-end to span the width of a Full Moon.
You know when you see the Moon in the sky during the daytime? Well, try this trick. Take a white round object, like a softball, and throw it into the sky, close to the moon. The shadow on the ball and the moon will be the same. They’ll appear to have similar “phases”.
By definition, a Moon is full when it’s 180 degrees opposite the sun. So if you see a big moon rising in east while the sun is still above the horizon, it’s not technically full yet. They can’t both be completely in the sky at the same time.
The moon causes most of our tides, but not all of them. The sun contributes about a third.
The moon rises about 49 minutes later each day. It’s orbital period is about 29.5 days. If you multiply 29.5 x 49.5 minutes, this gives 1446 minutes, or roughly 24 hours. Makes sense, when you think of it. One month later, you’ll see the same type of moon rise at about the same time. (Of course, this isn’t exact, I’m just approximating here, because the earth moves too. But you get the idea).
The First Quarter-Moon is defined when the sun and moon are separated by 90 degrees. Think of a right-angle triangle, with the earth at the square corner, and the Sun and Moon on opposite ends. Here’s another trick you can to do check this: Next time you see the quarter-moon during daylight, take two sticks (or ski poles, whatever) and point one towards the moon, and one towards the sun. You’ll see your arms make a nice 90-degree angle.
Okay, let me get this straight (some people still get this wrong). There is NO SUCH THING as the “Dark Side” of the moon!! Yes, there is a FAR SIDE of the moon, which we never see. But it’s certainly not always dark. It receives sunlight at least half the time, just the same as the Near Side does.
Getting back to the Full Moon. Like I said, it’s always opposite the sun. So during the summer months, when the sun is high in the sky, the Full Moon will always be low on the Horizon. Conversely, during the Winter Months, when the sun is low, the Full Moon will always be high overhead. At least, this is how it works in the Northern Hemisphere.
Use these tricks to approximate the time, if you don’t have a watch:
– A full moon rises at sunset, peaks at midnight, and sets at sunrise.
– The First Quarter-Moon rises at noon, peaks at sunset, and sets at midnight.
You’d think we’d only be able to see 50% of of the Moon’s surface, if the Far Side is always facing away from us. But actually, the Moon wobbles slightly when it orbits us, and some of the Far Side likes to play peek-a-boo. Not much…but enough that over time, we end up seeing 60% of the total Lunar Surface. This is called Libration.
The Full Moon is upside down in the Southern Hemisphere. (I knew this, but it still kinda freaked me out when I visited Australia).
The moon forms a very thin crescent when it’s almost directly between us and the Sun. Under these conditions (I’m sure you’ve noticed this), you can not only see the bright crescent part, but the entire dark part a well. (It’s not completely black, it’s more of a dark brown/grey). This is due to Earthshine. Just like the Full Moon brightens up our night time here on Earth, the “Full Earth” will brighten up the night time on the moon.
We get perfect total solar Eclipses because the Moon is almost exactly the same apparent size as the Sun. Is this a coincidence? Well, yes, actually it is.
Eons ago, or eons from now, the Moon’s orbit will change and we’ll no longer get total eclipses. Even now, the Moon’s apparent size varies slightly in it’s orbit, and there are times it doesn’t completely block out the sun. These are called “Annular”, or “Ring” Eclipses.
There are some crackpots who claim there’s a “Conspiracy Theory” and that we’ve never been to the moon. In 2002, a reporter confronted Buzz Aldrin, the second man to walk on the Lunar Surface. He called Buzz a “coward” and a “liar”.
Buzz punched him out, and rightfully so, I think.
And he was 72 at the time.
Buzz, that was AWESOME! 😀