Luna, how much do we really know?

It’s time to moon. Not yet with Artemis 1the demonstration mission of the namesake program for human return to ours satelliteforced to a further delay and to return to the garage (in the Vehicle Assembly Building) by the devastating Hurricane Ian. It’s time for the moon because the first of October is staged there International Moon Observation Nighta widespread event, in presence and online, promoted to admire ours satellite and know the projects that concern you. Why to the moon a large slice of space exploration has been dedicated and an equally large one will dedicate itself to it in the future, primarily with the program Artemis precisely. Because there is still a lot to discover, to explore, and also to know. Because maybe not everyone knows that …

At first it was “liquid”, perhaps

Let’s start from origins: we don’t know exactly how the Moon was formed. NASA itself speaks of chance when he mentions the most accredited hypothesis (also thanks to the analysis of the rock samples collected during the Apollo missions) to explain the birth of our satellite. According to this, the Moon was formed following the aggregation due to the effect of the gravity of the debris fired into Space after the collision of a planet the size of Mars with the Earth, about 4.5 billion years ago. In its first active life the newborn satellite it would have been in a liquid state, better melted. Other theories alternatives to the one known as del big splash“- but more problematic in terms of scientific evidence – advanced to explain the origin of the Moon are those of the multiple impact (ie the satellite would have been born from the debris of several objects and not just one that would have hit the Earth), that of fission (yes it would be detached from the rapidly rotating Earth), of capture (our planet would have grabbed it gravitationally), or co-accretion (according to which the two bodies, Earth and Moon, formed at the same time as a binary system).

The Moon does not have a “dark face”

We continue addressing one of the most talked about aspects when it comes to the Moon and still die hard: our satellite does not have a dark face. We incorrectly call the part of the moon which we do not see, since employing the moon a time of rotation on itself approximately equal to that of revolution around the Earth, always shows us the same face. What we do not see is not a dark face, but the face to us hidden. Until 1959, however: in that year, in fact, the Soviet spacecraft Moon 3 sent back to Earth the first images of the far side of the Moon, then conquered for the first time by the Chinese probe Chang’e-4 in 2019.

We always see the same face of the Moon, but this is not just half face. In fact, due to a process known as libration, we can see almost 60% of the lunar surface overall. This is due to the combined effect of the tilt of the lunar axis and the orbit described by the Moon around the Earth, which makes it travel faster when closer and slower when farther away. This makes sure that the visible portion of the satellite during his trip is more than 50%, adding small pieces both in longitude and in latitude. To convey the idea with a clear metaphor – like does Western Washington University – it is as if the Moon describing its orbit moves its head up and down and here and there, revealing itself a little more.

It (almost never) changes size in our eyes

We have all experienced it: the moon on the horizon it seems enormous, only to diminish once it rises to the sky. In reality – explains even NASA – the Moon has the same size, it is we who perceive it as bigger. In fact it is aoptical illusion. Small differences instead we could notice them during the events of Superluna, in which the Moon appears larger and brighter (respectively by 14% and 30%) when it is in the phase of flooding at the perigee, but these are really minimal differences at a inexperienced eye, hardly noticeable.

On the Moon we could jump much higher

There is no trick and there is no deception, simple effect of the reduced moon Gravity, about a sixth of that of Earth. This also means that on our satellite we would weigh one sixth of what we weigh on Earth.

We have nearly 400 kg of the Moon on Earth

The Apollo missions and Soviet spacecraft made it possible to bring a considerable amount of moon rocks to Earth. It is 382 kg of the Moon to be precise, most of which is kept at the Lunar Sample Laboratory Facility of the Johnson Space Center in Houston. Not a museum, but rather a strictly controlled lunar sample library to protect the samples from contamination or environmental hazards. To these almost 400 kg of Luna will be added that will be collected during the mission Artemis III and from the regions near the south pole of the moon.

There is also a “lunar influence”

Astronaut Harrison Schmitt called her “Moon dust hay fever”, referring to the annoying reaction experienced after the exploration of the lunar soil. A sort of allergy, with sneezing and nasal congestion that a said ESA would actually have affected all astronauts who have set foot on the lunar soil. The person responsible would be precisely there moon dust, extremely fine and very abrasive. It lifts easily and hangs for a long time, and sticks to everything. This is why NASA is also working to try to mitigate the problem of moon dust as much as possible. For the health of the astronauts and the functioning of the instruments that we will bring up there.