Interesting Facts About the Moon: Size, Water, Atmosphere, and More!

The moon is the closest large celestial body to us. An object of cultural, social and economic fascination. We know a lot about it, but even simple facts can surprise and provoke discussion. Let’s get to know some of them.

Humanity cannot exist without the Moon, as we recently wrote about. However, no matter how you approach the topic of exploring our natural satellite, you have to start with the question of survival. And water is important here.

The diameter of the Moon is 3,474 km and is 3.7 times smaller than Earth’s. The moon orbits the Earth at an average distance of 380,000 km at a speed of about 1 km/s. Inside, like the Earth, it has a liquid and a solid core, but weighs 83 times less. The moon was probably formed by the collision of the Earth with a celestial body the size of Mars.

You may have seen the movie “Silent Sea” where lunar water plays an important role. The film itself is a very far-fetched vision, but the topic of water is not nonsense. It’s there, and in huge numbers.

Lunar water is not just a resource stored in the form of ice in the permanently shadowed crater regions near the lunar poles, which is one of the reasons these sites were chosen for the Artemis mission’s landing sites. Water on the moon is everywhere because it can be extracted by processing lunar soil. A technology that extracts only oxygen from the soil has just been successfully tested.

The moon even has an atmosphere. Very rare, so its impact is minimal, and traces left by man can remain there unchanged for millions of years. Temperatures, on the other hand, range from minus 250 degrees C in the shadowed craters near the poles to as high as 130 degrees on the sunlit part at the equator.

Have you ever wondered what lunar regolith (layer of looser rock covering the surface) smells like? In videos taken during the Apollo missions, it rises like dust. It is better not to inhale it, because it has a rough structure and damages the respiratory tract.

Apollo mission astronauts had the opportunity to smell it after returning from a walk on the surface. Charles Duke Jr., of the Apollo 16 mission, claims it smells like used gunpowder.

Speaking of the Apollo mission, it is worth noting that conspiracy theories are often the result of a misunderstanding of the facts. Neil Armstrong’s first steps on the Apollo 11 mission to the lunar surface were actually recorded in a studio. It was a recording of a transmission from the Moon that was displayed on a screen. In those days, it was impossible to deliver the message directly.

You’ll say it’s bright because it’s fully illuminated. And this is a good answer, but when asked why the Moon less than 3 days before the full moon, when it is 95% visible, is already twice as dark as the full one, there will be doubts.

The high brightness of the Full Moon is a consequence of optics and geometry. Then sunlight strikes its surface perpendicularly, there are no shadows, except near the poles, and this is why the Moon is so bright. Therefore, when you want to observe lunar craters, it is better to do it outside of a full moon.

The fact that the size of the Moon in the sky is similar to the size of the Sun is a coincidence that allows you to observe spectacular solar eclipses. Interestingly, they are more frequent than lunar eclipses, but they cover a small part of the Earth, so you have to be lucky to be where they occur.

It turns out that it would take almost 400,000 moons to make it as bright as a sunny day. And since the half of the celestial sphere we can see from anywhere on Earth is made up of about 100,000 full moons, even wallpapering the sky with them wouldn’t make night into day.

The moon is nevertheless a bright source of light, although it only reflects sunlight. Interestingly, even when the Sun illuminates only a small crescent, you can see the glow of the part not directly illuminated, but facing the Earth. It is illuminated by sunlight reflected from the Earth. This phenomenon is called earthshine.

The surface of the Moon itself is dark, and although it appears light gray to the naked eye, it is actually as dark as asphalt. It looks white because it reflects sunlight. Half of the Moon is always illuminated at any given moment, but we observe the phases as the Moon changes its position relative to the Earth and the Sun.

A simple rule helps to recognize the phases of the moon. When its shape changes from D to O, we have time from new moon to full moon. When the letter O changes to the letter C, we have the time from full to new moon.

The moon is rapidly changing its position in the sky. The change in the height of the Sun above the horizon at the moment of towering occurs slowly with the period of the year. On the other hand, the Moon can tower at a completely different height after a week. For an observer from Poland, as small as 10 degrees above the horizon, but also as large as 70 degrees. It also rises almost two hours later each day.

The saying that the Moon is always turned with one side to the Earth is true, but only almost. It has a spherical shape, which means that less than 50% of its surface is fully visible from the Earth. At the same time, the Moon does not revolve around the Earth in a perfectly circular orbit, and the axis of rotation is not perpendicular to its plane. As a result, in the film of the pictures of the Moon taken at successive full moons, it will seem to sway. These are the so-called librations, which mean that within six years we are able to see 59 percent. the surface of the moon.

The video shows the changes in the position of the Moon relative to the observer throughout 2015.

The remaining 41 percent it is a part invisible from Earth, but already observed by satellites, people from the Apollo mission, explored by Chinese rovers. It is not dark and gloomy, as you can feel when listening to the Pink Floyd album, entitled “The Dark Side of the Moon”. When the Sun illuminates it in its entirety, for an observer from Earth, we have a new moon.

Will the moon be the same in a thousand or a million years? It will be a little more distant, because it is constantly moving away from the Earth, but its surface will not change significantly. Thousands of meteoroids fall on its surface every day, but there are few large ones. The lucky ones can observe such a collision even through binoculars as a brief flash on the part of the Moon that is not directly illuminated. Try it, maybe you will succeed.