Bill Nye- The Moon
Apr 11, 2009
Science rules. Inertia is a property of matter. Did you know that the earth goes around the sun? And the moon goes around the earth. In a very predictable cycle. Very predictable. Not everything's like that. Hey. See, the moon is always the same. It never changes. It's the same size and shape. Round like a boss, but it looks different to us here on earth because of the way sunlight hits it. That's right. Moonlight is really sunlight. And it changes because the moon is going around the earth, and the earth is going around the sun. Everything's just going around. Okay, now let's say that this baseball diamond is the orbit of the moon. Now, the diamond square in the orbits round, but you get the idea. Now we need a sun. So let's say that the earth is on the pitcher's mill. Now see, by the way, the scale of this globe and this moon are about right. With respect to the orbit of the moon. That's the baseball diamond. Now notice that right now, when you're standing on the earth, you can't see the moon at all. This is what we call a new moon. And the reason you can't see it is the moon is between you and the sun. Now the moon orbits the earth in this direction. So when the moon gets to first base, it's a half moon, because sunlight is falling on half of it. Then it keeps running to second. Now when the moon's back here at second, it's a full moon. That's because the moon is on this side of the earth. And here's the trick. The moon's orbit isn't flat. It's tilted. So a lot of times, when the moon's back here. Will be way up here. But notice it's still a full moon. And this is why most of the time, the earth's shadow doesn't fall on the moon. It's almost always full. Got to keep moving. On to third. So over here at third, it's a half moon again. But look, the shadows on the other side. That's because we're on the other side of the earth. Well, time to break for home. So with the orbit set up like this, the moon would end up right on home plate. The moon scores a home run. Every month. Well, that's astronomy for you. Our baseball. I guess it's both. You know, sometimes you can see the moon during the daytime. Each week, the moon looks different. Sometimes it's round, sometimes it's a teeny sliver, and sometimes you can't even see it. Here's a fun thing to do. Look at the moon. Sometimes you can see it during the daytime. Draw what you see on your window. Don't worry. It's just so you can watch it when you're done. Look at the moon in a couple of days. And try it again. When the moon's not there. That's called a new moon. Just draw a dotted circle. After a month, the moon starts the whole thing over again. And that part always goes from the right to the left. The moon's in your room. Cool. Moon glow is really sunglow. That's right. Moonlight is really sunlight that reflects off the surface of the moon, like a mirror. You say, well, how can moonlight be so bright? I mean, where does it all come from? Well, two things. First of all, the moon doesn't have as much gravity as the earth. So it can't hold on an ocean or an atmosphere which absorbs moonlight. And moon rocks reflect a lot of light. You know, moon rocks are a lot like earth rocks. They have a lot of the same minerals, minerals like potassium. Potassium is in bananas. Now, one of the reasons that scientists think that moon rocks and earth rocks are so much alike, is that perhaps the earth was hit by a giant meteorite, a giant rock in space. It hit the earth, and that material spun off and formed the moon. So moonglow is really sunglow, reflecting off of moon rocks. Huh, wow. Glow figure. Oh my God. Hey. Thank you for flying tonight, airlines. Chicken and fish. Community access 27. Next, the high daily school. With the moon. And now miss Marshall's fourth grade class presents the moon, a play in two acts, act one. The revolution. So where did the moon come from anyway? Well, our best theory right now is that the ancient earth was hit. By a giant asteroid, big rock from space. Of course in space, there's no sound. So be more like. Anyway, this material was melted, molten. After a while, a piece of it got flung off and the pull of gravity held it in orbit. And that's our moon. Now, because the moon was formed by this impact, the moon's.