Welcome to Brainstuff, a production of iHeartRadio. Hey, brain Stuff, Lauren vogelbaumb here. You've probably noticed that when you look up at the Moon, you always see the same features. You can see craters and patches of lighter and darker areas. With a pair of binoculars or a telescope, you can make out even more detail. But no matter how you look at the moon, you're always seeing the same landscape. But the Moon is a sphere. If we're only seeing
one hemisphere, then what's on the other side. This is the so called dark side of the moon, the side we never see because it always faces away from Earth. For this reason, people also use the phrase the dark side of the Moon to describe something mysterious or unknown. This side of the Moon faces the cold, black, expansive space. What could be on this side of the moon? And is it really always dark? We actually know what it
looks like, and no, it is not permanently dark. We have lots of images from various lunar missions, and in nineteen sixty eight, astronauts aboard the Apollo eight spacecraft were the first humans to set eyes on it in person. But the popularity of the phrase means that there is ample opportunity for people to jump to the wrong conclusion, especially since we only ever see that one hemisphere, and it's easy to misunderstand the cause of the phases of
the moon that we see from Earth. But mostly this is a problem with terminology. The descriptor dark side suggests that shadows perpetually cloak the surface of the side of the Moon that faces away from us. It's fun to imagine a dividing line between the light side and the dark side, but that's not how it works. While it is true that some part of the Moon is dark at any particular or time, it's not always the same part.
That's because like Earth, the Moon rotates on its axis, a meaning it has a daytime and a night time. So if you were to set up camp on the Moon and stay put, you would eventually see the sun rise and fall. You'd experience both day and night. So technically the moon does have a dark side at any given moment, but it shifts. The dark side is the part currently experiencing night. The side of the moon we see is sometimes the day side, sometimes the night side,
and sometimes a bit of both. A more accurate term to describe The side of the Moon that we always see is the near side. The side opposite is the far side. The near side will always be facing toward us, and the far side will always face away. This is true from anywhere on Earth. If you were to fly from America to Australia or vice versa, you'd see the same features that you're familiar with back home. But why do we only ever see one side of the Moon
from Earth? Okay, it takes about twenty nine days for the Moon to make one complete orbit around the Earth. That's also how long it takes the Moon to make one rotation on its axis. Because the Moon's rotation and orbit take the same amount of time, we always see the same face of the Moon no matter when we look at it. The Moon just keeps spinning the same side of itself toward us as it orbits around us.
This happens because of gravity. Earth's gravitational pull on the Moon is so strong that our planets slowed the Moon's rotation down to its current speed. Its rotational speed is locked with the time that it takes to orbit the Earth. Interestingly, the Moon is doing the same thing to the Earth, just much slower because the pull of the Moon on the Earth is much smaller, so if you've ever felt like the days are getting longer, they are technically still.
In a few billion years, the Earth's rotation will match the time it takes the Moon to orbit the Earth. By that time, the Moon and the Earth will have drifted apart from each other a little bit, which means it'll take a little longer for the Moon to travel around the Earth, to the tune of about forty days or so, meaning that in the distant future, one Earth day will equal forty of our current Earth days, or
about nine hundred and sixty hours. Once the Earth's rotation matches the time it takes for the Moon to orbit the Earth, the same side of the Earth will face the Moon all the time. But okay, let's talk about the phases of the moon. A common misconception about the moon is that it appears as just a sliver sometimes called a new moon, when the Earth is between the Sun and the Moon, thus blocking the light from the
Sun and casting a shadow across the moon. But in reality, during a new moon, the Moon is between the Sun and the Earth. Imagine that you're in a room that's dark except for one window that has sunlight shining into it, and then someone walks between you and the window. You would see the person in silhouette. They'd appear mostly shadowy, but with a bright outline along their side facing the window. That's exactly what a new moon is. A full moon, in contrast, is when the Earth is between the Moon
and the sun. Going back to our example, imagine that you're the person standing by the window. If you turn to look into the room, anyone standing there would be well illuminated. That's the same as us looking at a full moon. But again, whether it's a full moon or a new moon, you're still looking at the same side of the moon, the near side. During a new moon, you're looking at the near side during lunar night time, and during a full moon you're looking at the near
sides version of noon. All of this being said, the far side of the moon is still a little mysterious because the Moon's bulk blocks radio signals to and from the Earth from its far side. Engineers don't yet have a good way for us to explore that far side. In the future, we may see NASA and other organizations build radio relay towers on the Moon's surface to make exploration possible. Until then, we'll have to content ourselves with
being looney over the side that faces us. Today's episode is based on the article what and Where is the Dark Side of the Moon on HowStuffWorks dot com written by Jonathan Strickland. Brain Stuff is production of iHeartRadio in partnership with hostuffworks dot Com and is produced by Tyler klang A. Four more podcasts my heart Radio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows.