The Moon has been the subject of human fascination for millennia. Chances are good that you’ve gazed up at a beautiful full moon at least once in your life. Maybe you've even watched a lunar eclipse. But beyond seeing it every night and having a vague sense that it affects the tides here on Earth, what do you really know about the Moon? If you're curious, then you're in the right place, because we’ve put together a list of facts about the Moon to help you learn more about it. So, are you ready to discover something new today? Read on!
#1 The Moon Is (Largely) Responsible for Tides on Earth.
The Moon’s gravitational pull creates tidal force. This tidal force causes Earth – and the water in the ocean – to bulge out on the side that is closest to the Moon as well as on the side that is farthest from it. These bulges of water are what we know as high tides. Low tides occur in the areas where the Moon’s gravity is not pulling on the Earth. As the Earth rotates, different parts of Earth experience high tides and low tides. The cycle of two high tides and two low tides happens on most days on most of Earth’s coastlines. The Moon's effect on the tides happens because it is so close to Earth that even though it only has about 1/100th the mass of Earth, it still has enough gravity to move things on Earth’s surface. The tidal force is most noticeable in the ocean, but it actually shifts the land infinitesimally as well! The Sun can also affect tides on Earth, although to a lesser degree. Water levels are also affected by things like wind and weather patterns.
#2 The Moon Doesn’t Generate Its Own Light.
While we see the Moon shining brightly in the sky each night, the fact is, the Moon doesn’t actually produce its own light. The glow we see is there because the Moon reflects light from the Sun. More specifically, the Sun’s light reflects off of old volcanoes, craters, and lava flows on the Moon’s surface. This reflected light from the Sun is visible from Earth. This means that what we commonly refer to as moonlight is actually just the Sun's light reflecting off the Moon.
#3 Temperatures on the Moon Can Vary Drastically.
The temperature on the Moon can vary drastically, ranging from tremendously hot to extremely cold. When the Sun hits the surface of the Moon, the temperature can reach a scorching hot 127°C. However, when the Sun isn’t hitting the Moon’s surface, temperatures can drop to a chilling -153°C. These massive fluctuations in temperature occur because the Moon does not have a significant atmosphere and cannot trap heat. So when the Sun isn't shining on the Moon's surface, it is extremely cold. And while the Moon does have an inner core, it’s not hot enough to warm the surface of the Moon.
#4 We Don’t Know Exactly How the Moon Formed.
We don’t know exactly how the Moon formed, but scientists have a few theories, and all of them are pretty fascinating. The prevailing theory is based on recent evidence. It suggests that the Moon formed when a huge collision tore a chunk of the primitive molten Earth away and the raw ingredients for the Moon were sent into orbit. Based on the similarities in composition between the Earth and the Moon, scientists believe that this impact took place approximately 95 million years after our solar system first formed. While this is the dominant theory, others do exist. Some scientists believe Earth captured the moon, others subscribe to the theory that the Moon fissioned out of Earth, and still others posit that Earth stole the Moon from Venus.
#5 Earth and the Moon Are Tidally Locked.
Tidal locking happens when a given body has the same rotational period as its orbital period around another body; this is due to gravitational distortions induced by one body on another. The Moon orbits Earth once every 27.322 days and it takes approximately 27 days for the Moon to rotate once on its axis. This means that the Moon and the Earth are tidally locked. In fact, the rotations of the Earth and the Moon are so closely in sync that we only ever see one side of the Moon. Humans didn’t see the lunar far side (sometimes erroneously referred to as the “dark side of the moon”) until a Soviet spacecraft flew past it in 1959. Interestingly, the lunar far side looks very different than the side of the Moon that we see – that's because while the near side of the Moon is smoothed out by maria (large dark plains created by solidified lava flows), the lunar far side is heavily cratered.
Want to learn more facts about the Moon? Watch this video to find out more!