Unmasking the moon. Surprising truths from water pools to gunpowder scents

Without the moon, human existence as we know it can't be sustained, an idea we've recently touched upon. Irrespective of how exploring our only natural satellite is approached, survival becomes the crux of the matter. Here, water is fundamental.

The moon's diameter is 2,159 miles, making it 3.7 times smaller than the Earth. It orbits the Earth at an average distance of 236,121 miles, moving at a speed of roughly 0.62 miles per second. Just like the Earth, the moon possesses a liquid and solid core but weighs 83 times less. The moon's formation is widely believed to have been caused by an impact between the Earth and a celestial body the size of Mars.

The movie "Silent Sea" may have introduced viewers to the concept of lunar water, a significant plot element in the film. While the movie's depiction borders on the speculative, the presence of water on the moon is rooted in fact, available in sizeable quantities.

Water on the moon isn't just an ice deposit confined to steadily shadowed crater regions near the lunar poles. It's found across the moon and it can be extracted via processing the lunar soil. The very same technology enabling oxygen extraction from the soil has recently been successfully tested.

The moon even possesses an atmosphere, albeit a thin one. Its presence is so faint that human footprints could potentially remain unchanged for millions for years. Temperatures on the moon have an extremely wide range, from -418 degrees Fahrenheit in the shadowed polar craters to a scorching 266 degrees in sunlit equatorial regions.

Have you ever pondered what lunar regolith, a layer of loose debris that covers the lunar surface, smells like? Videos from the Apollo missions depict it looking like dust, and it's ill-advised to inhale as the rough texture can harm the respiratory tract.

Apollo astronauts got a whiff of the lunar regolith upon returning from their moon walks. Charles Duke Jr. of the Apollo 16 mission likened its scent to that of spent gunpowder.

On the topic of the Apollo missions, it's fitting to mention that conspiracy theories often arise from a misunderstanding of the facts. Neil Armstrong's first steps on the moon during the Apollo 11 mission were indeed captured in a studio. However, this was simply a re-recording of the transmission from the moon, as directly transmitting the footage was technologically unfeasible at the time.

One might logically conclude that the full moon's brilliance is due to it being completely illuminated. However, when asked why the moon, when it's less than 3 days shy of fullness and 95% visible, already appears twice as dim, doubts begin to surface.

The heightened luminosity of a full moon can be attributed to optics and geometry. At this stage of the lunar cycle, sunlight strikes the moon's surface at a right angle. Hence, shadows are cast only around the poles. This is why the moon shines so brilliantly. If your objective is to observe lunar craters, it would be wise to do so outside of the full moon phase.

In a happy twist of fate, the comparable sizes of the sun and the moon in the sky enable us to witness awe-inspiring solar eclipses. Interestingly, solar eclipses happen more often than lunar eclipses but only cover a minuscule portion of the Earth. Thus, viewing one requires being in the right place at the right time.

Approximately 400,000 moon-sized bodies would be required for the moon to appear as bright as a sunny day. Considering half the celestial sphere, visible from any location on Earth, spans nearly 100,000 full moons, even filling the sky with moons wouldn't convert night into day.

Despite being a second-hand source of sunlight, the moon is incredibly luminous. Intriguingly, even when only a slim crescent is directly sunlit, earthshine, the phenomenon of sunlight bouncing off Earth and reaching the moon illuminates the otherwise dark portion facing Earth.

The moon's surface is dark, mirroring the shade of asphalt. The moon appears light gray to the unaided eye, but it seems white when full because it's reflecting sunlight. As the moon changes its position relative to the Earth and the Sun, we observe lunar phases, but half of the moon is illuminated at any given instant.

To track the phases of the moon, a simple rule comes in handy. When the moon transforms from a D to an O shape, it signifies the period from a new moon to a full moon. Conversely, a transition from an O to a C shape marks the period between a full moon and the subsequent new moon.

The moon alters its position in the sky rapidly. While the sun's altitude changes slowly with the annual cycle, the moon can culminate at vastly different altitudes within a mere week. From Poland, it can be seen as low as 10 degrees or as high as 70 degrees above the horizon. Furthermore, the moon rises almost two hours later each day.

The adage that the moon always presents the same side to the Earth is close to reality. As it's a sphere, less than 50% of its surface can be sighted from Earth during a full moon. Also, the moon doesn't follow a perfectly circular orbit around the Earth, and its axial rotation isn't perpendicular to its orbital plane. Consequently, a sequence of full moon photos would exhibit an oscillation effect. These oscillations, termed librations, enable us to see approximately 59% of the moon's surface over six years.

The remaining 41%, though unobservable from Earth, has been examined by satellites, Apollo astronauts, and Chinese rovers. Contrary to the underlying theme of the Pink Floyd album "The Dark Side of the Moon", this hidden side isn't perpetually dark and sinister. When it's fully sunlit, it's a new moon phase for an observer on Earth.

Will the moon look different in a thousand or a million years? While it will be slightly farther away because of its continuous retreat from Earth, considerable changes to its surface aren't anticipated. Numerous meteoroids fall on it daily, but few are large. Lucky observers might spot such an impact through binoculars, visible as a fleeting flash on the dark side of the moon. Give it a shot; you may get lucky.