How craters appeared on the moon. The moon and its craters

In today's article I would like to tell you a little about our companion, the Moon. Selena, as it is also called, is the brightest object in the night sky and has always attracted people's attention to herself. Astrolamists also call her the “most grateful” object of observation! I would also like to join this expression and note that so many emotions, so much interest, with telescopic observations, few objects in the sky can give.

This shot, gigantic, was filmed through a 200mm telescope together with Alexei Yurchenko, near the village. Izmailovka. It is a mosaic of 19 frames.

Happy viewing!

A little about the moon.

The moon is Earth's companion in outer space. The Moon makes a complete journey around the Earth every month. It shines only with light reflected from the Sun, so that constantly one half of the Moon, facing the Sun, is illuminated, and the other is immersed in darkness.
The study of lunar rocks delivered to Earth made it possible to estimate the age of the Moon by the method of radioactive decay. The rocks on the moon became solid about 4.4 billion years ago. According to the theory of the Russian astronomer Evgenia Ruskol, the Moon was formed from the remnants of protoplanetary matter that surrounded the young Earth. Another theory was developed by the American astronomer Alistair Cameron: he believes that the Earth at the stage of formation collided with a large celestial body. The debris thrown out as a result of the collision merged into our satellite.

When the moon can be seen.

Often people believe that the moon rises into the sky only at night; in fact, if the sky is clear, then a faintly luminous moon can often be seen during the day. The time of moonrise is getting later day by day. Immediately after the new moon, the moon rises after the sun. A week later, when the first quarter of the cycle passes, the moon rises at noon, and the full moon rises at sunset.

The ebb and flow is familiar to everyone who lives or has been on the ocean or sea coasts. Twice a day, the level of ocean waters rises and falls, and in some places by a very significant amount. Every day the tide comes 50 minutes later than the previous day. What makes the ocean waters rise and fall back? Luna is to blame for everything.

The moon is held in its orbit around the Earth for the reason that there are gravitational forces between these two celestial bodies, attracting them to each other. The Earth all the time seeks to attract the Moon to itself, and the Moon attracts the Earth to itself.

Because the oceans are large masses of fluid and can flow, they are easily deformed by the gravitational forces of the moon, taking the shape of a lemon. The ball of solid rock, which is the Earth, remains in the middle. As a result, on the side of the Earth that is facing the Moon, a water bulge appears and another bulge of the same kind - on the opposite side. As the solid Earth rotates on its axis, the ocean shores ebb and flow, this happens twice in every 24 hours and 50 minutes as the ocean shores pass through the water bumps. This time the length of the period is more than 24 hours due to the fact that the Moon itself is also moving in its orbit. In bays and estuaries of rivers, the ebb and flow are more significant than in other places, since in narrow passages seawater collects, like in funnels.

In the 17th century, the Italian astronomer Giovanni Ricciolli appropriated the names of the heights and troughs on the Moon: Alps, Apennines and the Caucasus, Ocean of Storms, Seas of Rains, Cold and Calm, Tycho craters, Pythagoras, Ptolemy, etc. At the suggestion of Soviet astronomers, the International Astronomical Union placed 18 names of newly discovered formations on the first map of the far side of the Moon. This is how the Sea of Moscow, the craters Hertz, Kurchatov, Lomonosov, Maxwell, Mendeleev, Sklodovskaya-Curie, Tsiolkovsky appeared on the moon.

Of course, there are no seas on the moon. The lunar seas are completely dry and are vast, once-flooded with basaltic lava lowlands. The moon is a lifeless body devoid of atmosphere, seas and oceans. During the lunar day, the surface temperature can change by 300 degrees (from –170 ° C to + 130 ° C). Under such conditions, water cannot be in a liquid state.

Craters.

All lunar craters have an impactful nature of occurrence. All these are traces of a super-long cosmic bombardment, which the Moon manically keeps as a keepsake. There are innumerable craters on it, in fact, almost the entire surface - and the old craters are clogged with new ones almost beyond recognition. Craters are large and small, light and dark, young and old, with or without rays.
Craters are called by the names of various great scientists, possibly related to astronomy. This idea was introduced by those same Italians-cartographers of the 17th century - Giovanni Riccioli and Francesco Grimaldi - whose names of lunar objects stuck best of all.

And so let's take a look at the light version of the Moon map, pay attention to all sorts of dots and scratches.

Light points are best seen - these are they, in the sense of craters. Moreover, it is the young ones. The fact is that the surface of the seas is basalt, frozen lava is dark in itself. The usual continental surface is gray, it is affected by solar radiation, because of which it darkens. And what is dug up by the impact of an asteroid is light, it is the interior of the lunar crust.

Let's start with the most noticeable lunar crater - Tycho crater. This is the "navel" of the moon. Like a plug in a balloon.

Its diameter is 85 kilometers (not the largest), but it is possible, for example, to shove the entire city of Istanbul into it, and there will still be room.

Crater Tycho of the young - it is 108 million years old - is bright and fresh. Well-visible rays radiate from it - these are traces of lunar rock emissions after impact. It hit hard, that's why it flew far away; some rays stretch for thousands of kilometers and are visible as far as the Sea of Clarity and beyond.

In the center of the crater there is a characteristic slide. When anything more than 26 kilometers in diameter flies into the moon, solid rock begins to behave like a liquid at the impact site. Photos of a drop falling into water, I hope everyone has seen it? In the Moon, about the same thing happens - and after the impact, the surface swells up with a backward damping wave.

The crater is named in honor of the famous Danish astronomer and alchemist Tycho Brahe, who lived in the second half of the 16th century and managed to create the first scientific astronomical center in history - Uraniborg. In addition, he was the first to find out the nature of comets, with the help of his own invented instruments, he increased the accuracy of sky observations by an order of magnitude, saved Johannes Kepler from persecution - and did a lot of other heroic things.

There is a stupid childhood legend about Tycho Brahe, which my mother used to tell me as a child. As if he died at a royal reception, right at the dinner table. I really wanted to write, but hesitated to go out - so the bladder ruptured. And this is, as it were, incompatible with life. It is not clear where this nonsense came from, maybe it even lasts since 1601: the astronomer's illness proceeded so rapidly (11 days) that many then suspected that something was wrong and began to offer versions, some more stupid than others. Until now, by the way, they are busy with the remains, they cannot determine the exact cause of death.

The next crater is just the name of that young German mathematician whom Tycho Brahe wrote to him a year before his strange death. Johannes Kepler came to Prague at the invitation of the replaced astronomer in 1600 - and stayed there. Based on materials that remained from Tycho Brahe, extremely accurate for their time, Kepler deduced the laws of planetary motion, which are still relevant to this day. They are called so - Kepler's Laws, and thanks to them the heliocentric system of the world received the final scientific confirmation.

If you look closely at the Kepler crater, you can also see a system of rays, although not as frenzied as that of Tycho. Its diameter is 32 kilometers. He is about the same time of education, but a little older. One of the rays clearly stretches from Tycho to Kepler - everything is like in life.

But next to Kepler, Copernicus crater is clearly visible, also from young and with rays. Who is the Polish astronomer Nicolaus Copernicus, the author of the concept "The sun is in the center", probably it is not necessary to tell. The name of this crater, as well as the above, was given in 1651 by the same Giovanni Riccioli, an Italian Jesuit and astronomer.

What Copernicus "dug up" deeply blew up the mainland rock below the level of the basalt sea - that is why he is the only one so "smart in a white coat is handsome."

Copernicus' diameter is 95 kilometers, the rays stretch for 800 kilometers, its age is 80 million years. In selenochronology, a whole epoch in the history of the Moon is counted down on the Copernicus crater, which continues to this day and is called the "Copernicus era". All bright craters with a whole ray system belong to this era. At the same time, Copernicus himself was formed almost at the very end.

To the left of these worthy in all respects craters is the Aristarchus crater. This is the brightest area on the Moon - which is clearly visible even in such a filthy photo. Its diameter is 45 kilometers, its age is 450 million years.

It is named after the ancient Greek astronomer of the 3rd century BC. Aristarchus of Samos, who, oddly enough, is also considered the author of the concept "The sun is in the center". Whether Copernicus knew about his idea is considered unknown.

Aristarchus is the most mysterious crater of the Moon according to all observations. First, it has a very complex bottom structure. Secondly, a variable flux of alpha particles (radon deposits) was recorded from it. And thirdly, Aristarchus holds the record for the so-called short-term lunar phenomena (KLA), which have no explanation yet. These are not just sparks from meteorites, but more complicated things: changing spots, changing brightness, fogging, multi-colored glow, and so on. In 1970, it was described how a blue spot appeared for 10 seconds in Aristarchus for three nights in a row. Then it disappeared for 10 seconds. And it appeared again. The devil knows that.

In general, if you set up a household telescope on the balcony and engage in targeted observation of Aristarchus, there is a good chance to witness what humanity is unable to explain.

Here he is, handsome, in a 2012 NASA photo (sun on the left):

Just above the center of the lunar disk, near the boundaries of the Sea of Clarity, there is a pair of approximately identical craters with approximately the same names - Manilius and Menelaus.
Mark Manilius is a Roman astrologer of the 1st century A.D., known in the history of the world for the first book on astrology. It was called "Astronomicon" and was all in verse in the fashion of that time.
And Menelaus is not the horned husband of Helena from Homer's poem, but even Menelaus of Alexandria, the ancient Greek mathematician and astronomer, who lived at the same time as Manilius. Menelaus is famous for his work "Spherica", in which he outlined the laws of calculating triangles lying on a ball.

And the last two craters of the clearly visible ones remained - on the left and right on the sides of the lunar disk, like carnations. The dark carnation on the left is the Grimaldi crater, and the light on the right is Langren.
I have already stated about Francesco Grimaldi above. Physicist, Jesuit monk, the one who, together with Giovanni Riccioli, gave all the main names for lunar objects. I must say that not far from it there is a crater and its colleagues, but it is poorly visible.

The darkest color of the Moon's surface is recorded in Grimaldi Crater. This is one of the most ancient craters, its formation is attributed to the Donektarian period.

The court astronomer and cartographer of the Spanish king, the Flemish Mikael van Langren, who lived in the 17th century, like the Italians-Jesuits, was also engaged in lunar topography and gave his names to various objects. Another thing is that almost all of them have not survived - who is interested in the names of officials of that time. Bad choice. But the crater, which he called by his own name, unexpectedly retained its name to this day.

And the last - from the modern excitement around the moon. The term "supermoon" really exists in astronomy. It means the coincidence of the full moon and the perigee of the lunar orbit. The orbit of our satellite is not an even circle with the Earth in the center, but an ellipse. And while the Earth is not in the center. Therefore, the Moon either approaches us (the closest point of the orbit is perigee), then moves away (the farthest point is apogee). But even at this very perigee, the visible lunar disk increases by no more than 14%. And the visual effect of increasing the size of the moon usually occurs always when it is low above the horizon. In this case, the atmosphere works like a lens.

But not "twice as much as usual," as some illiterate media outlets say.
Moreover, the Moon is gradually moving away from the Earth at a speed of about 4 centimeters per year - this is a consequence of the history of its formation (giant collision theory).

Photo prepared for the group

Space flights to the Moon led to the rapid development of research in the field of selenology, selenochemistry, and selenophysics. The moon has become one of those celestial objects, the study of which helps to better understand the structural features of the Earth and other planets of the solar system.

However, nature jealously guards and sparingly reveals its secrets. So it was with the back of the moon ball. For many centuries, people could not look beyond the hemisphere of the moon visible from the Earth and only made their assumptions. The main secrets of the invisible side of the moon were revealed in 1959, when the Soviet automatic interplanetary station "Luna-3" flew around the moon and photographed its reverse side. These were the first photographs transmitted from outer space, published in Atlas of the Far Side of the Moon, Part 1, edited by N.P. Barabashova, A.A. Mikhailova and Yu.N. Lipsky. At the General Assembly of the International Astronomical Union, held in the United States in 1961, at the suggestion of Soviet astronomers, 18 names of newly discovered key formations on the far side of the Moon were placed on the map. Among them: the Sea of Dreams, the Soviet Ridge, the Tsiolkovsky craters, Giordano Bruno, Lomonosov ... Behind these formations was the main secret of the far side of the Moon, which will be discussed below.

Another side of the moon. The dotted line represents the approximate boundaries of the South Pole-Aitken Basin.

At present, the results of a topographic survey of the surface of bodies in the solar system show that the ring structure on the far side of the moon, including the region of its south pole, is the largest crater in the solar system in terms of its absolute size. The relative dimensions of this structure are such that, if one adheres to the traditional views on the processes of impact cratering, the initial depression of the giant formation could open up rocks at a depth that corresponds to the occurrence of the upper layers of the lunar mantle. Already these circumstances determine the fundamental importance of studying the multi-ring structure, which currently has the working name "South Pole - Aitken Basin".

The first images of this largest structure in the solar system were taken during the first photograph of the far side of the moon in 1959. The position of the structure, observed from four photographic images at the edge of the visible disk in the form of a darker formation, was determined by the central darkening with a diameter of 1500 km and coordinates of the center 179 ° E. and 50 ° S. On the map, which was compiled in 1960 from photographs obtained on October 7, 1959 by the interplanetary station "Luna-3", this formation, as emphasized above, was called the Sea of Dreams.

The modern parameters of the inner dark ring of the basin were determined from the images and the results of laser altimetry performed by the Galileo and Clementina spacecraft. According to these data, the diameter of the dark central part of the basin is 1400 km, the diameter of the outer ring of the basin reaches 2500 km, and the coordinates of the center are 180 ° and 50 ° S. (at the 34th Russian-American microsymposium on comparative planetology in October 2001, in the report of V.V. Shevchenko and the author of this article, based on an analysis of the data obtained by the Zond-8 and Clementine vehicles, it was concluded that that the diameter of the outer ring of the basin reaches 3150 km). As you can see, the first identification of the basin position, made by Soviet astronomers back in 1960, was quite accurate and completely reliable!

Even in the first descriptions of the western part of the structure, it was noted that its surface includes numerous craters and crater seas. This also fully coincides with modern ideas about the nature of the bottom of the pool.

The huge basin occupies the entire southern half of the invisible hemisphere of the Moon, the southern polar cap and the southern regions of the marginal zones of the visible hemisphere of the Moon. Therefore, part of its outer annular shaft, passing near the south polar cap, can be seen through a telescope from the Earth's surface. Here, south of the 60th parallel, there are such large craters of the visible hemisphere of the Moon as Bayi 287 km in diameter, Newton (78 km), Malapert (69 km), Scott (103 km), Demonax (128 km), Schomberger (85 km) , Helmholtz (94 km) and others, belonging to the southern edge of the basin. The heights of their smoothed destroyed shafts reach two, three and even four kilometers, they are all located on the continental surface, they practically do not have light ray systems, which indicates their ancient age. Relatively young of them, for example, Schomberger, are distinguished by a better preserved and more distinct shaft.

According to lunar geologists, the giant basin was formed 4.2 billion years ago as a result of a very large impact, when the crust and mantle had already differentiated, and the crust had hardened so that the impacts had already begun to leave visible traces on the lunar surface. Then, on the surface of this giant formation, other, more modest ring basins and craters began to appear, which, however, for more than four billion years, were not able to completely blur out the consequences of the explosion, as a result of which this giant basin was formed. It is quite obvious that a more accurate knowledge of the topography of the South Pole - Aitken Basin is highly relevant for the construction of any real models of its origin.

Since the observed diameter of the ring formation exceeds 1.8 lunar radius, the restoration of the mechanism of the formation of this shock structure is undoubtedly a fundamentally important task in the study of the evolution of planetary surfaces.

As a result of the action of numerous impacts of meteorites and volcanism over several billion years, many details of the rings and emissions from the basin, of course, were erased and destroyed, therefore, in the images of the Lunar Orbiter spacecraft that appeared in the second half of the 60s, the decoders of objects could not to detect in these images the outward signs of the outlines of a giant basin. Therefore, as a compromise, the boundaries of the entire formation were reduced, and the name "Sea of Dreams" on the map was assigned only to a small structure with a diameter of about 270 km in the northwestern part of the basin. The existence of the giant basin was confirmed only after 1971 by B.N. Rodionov et al. In a series of publications containing the results of measurements of limb profiles in the images delivered by the automated probes Zond-6 and Zond-8 returned to Earth. In these publications, the basin was called the Southwest Lowland, but this name did not receive further official recognition.

A similar fate befell the name "Soviet Ridge": it simply disappeared from the surface of modern maps of the far side of the Moon! And this is despite the fact that the bright area found in the first images of the far side of the Moon remains a very real lunar formation. Other images taken from space, including the Clementine, also confirm the presence of a mysterious area with many bright details.

And here is what the description of the Soviet Ridge looks like in the original source, i.e. in Atlas of the Far Side of the Moon, Part 1: “The Soviet Ridge is a bright formation against a gray background, consisting of a large number of separate bright details. The general contour is elongated in a northeasterly direction, expanding noticeably in the equatorial region. By its reflective properties it resembles mountainous areas ... Object coordinates: from 118 ° E up to 124 ° E and from 9 ° N to 5 ° S ". As shown by comparisons with the data obtained by "Clementine", the above-mentioned area of the "disappeared ridge" exactly coincides with the western slope of the northwestern part of the outer ring of the basin, the individual peaks of which here reach three or even four kilometers.

Profiles of the South Pole - Aitken Basin from north to south (dashed line) and from west to east (dash-dotted line).

Thus, the Soviet Ridge, discovered from the first images of the far side of the Moon in 1960, is associated with a giant basin in origin, since it is part of the northwestern link of its outer annular wall, which has survived to the present day!

So the secrets of the far side of the Moon lie on its surface, no matter how they are erased over several billion years. Subsequent impacts and volcanic activity could not definitively destroy the giant rings and large traces of emissions, clearly genetically related to the basin. And now, after 4.2 billion years, we are witnessing this grandiose event, which took place by cosmic time standards almost immediately after the formation of the lunar ball.

Chikmachev Vadim Ivanovich
candidate phys.-math. Sci., Senior Researcher, Department of Moon and Planets Research, GAISH.

But first, a photograph of the Moon with the announcement and location of those objects that will be discussed with this article:

Probably the most famous crater on the moon, many do not know its name, but they definitely see it on the moon. It can be "guessed" even with the naked eye at the full moon, because at the full moon it is the brightest spot on the moon due to the rays emanating from the crater up to 1500 km in length

The crater was formed on the moon about 100 million years ago, with an average diameter of 85 km and a maximum depth of almost 5 km. By Lunar standards, the crater is considered young. At an approximation of 5000 mm, the stepped structure of the inner shaft on the walls of the crater is clearly visible. And also the central hill of the crater is divided into separate rocks, which reaches a height of about 2 km.

I think that the second most recognizable is Copernicus crater. It is clearly visible, both during the full moon and in other phases of the moon, when it is illuminated by the light of the sun. Its good visibility is due to the fact that the crater is located in the middle of the Ocean of Storms, in a dark volcanic rock, and those emissions that appeared as a result of the collision have a lighter color, due to this, it contrasts on the surface of the Moon.

In my opinion, a very interesting crater. At different phases of the moon, it looks completely different, due to the play of light and shadows. This time it was almost completely illuminated, and it seems a little flat, but the shadows do not hide its entire inner terrace-like structure. The age is estimated at 800 million years, almost 4 km deep and about 96 km in diameter. Around Copernicus, you can observe a huge network of secondary small craters formed by rock debris as a result of the explosion when the meteorite that created Copernicus fell. An interesting detail is that the Apollo 12 astronauts took soil samples from the ray structure of this crater.

By its visible nature, it is very similar to Copernicus, and they are located in the neighborhood.

The crater is relatively small, about 30 km in diameter and 2.5 km deep. But due to the dark basalt plateau of the Ocean of Storms and the Sea of Islands, it stands out strongly on the surface of the Moon with its light ray system.

4) Clavius Crater
The most beautiful crater on the moon. It is beautiful precisely because of its structure of secondary craters, it is easily recognizable, it reminds me of a funny cartoon face.

Located at the south pole of the moon, under the Tycho crater. It is a very ancient crater with an age of about 4 billion years, a diameter of 230 km and an average depth of about 2 km, and a maximum of about 5. Two craters that hit the moon later and smashed the walls of Clavius are called Porter (upper) and Rutherford (lower). They are almost the same size, 50 km in diameter.
An interesting feature of Clavius is its bottom. It is quite flat apart from the falls of younger meteorites. A little to the left of the center of the crater is the "central hill", which for some reason is offset from the center. It is assumed that the bottom of the crater was formed much later than its formation.

A crater with a very interesting bottom, with numerous grooves and faults

Located on the northern edge of the Sea of Moisture. An ancient ruined crater with a diameter of 110 km. and relatively shallow depth: 1.5 km. Against this background, the central hill looks higher than the walls of the crater, although in fact its height is slightly less than 1400 meters. The structured crater floor owes its appearance to the formation of the Sea of Moisture. During this period, the crater underwent lava corrosion.

A small round lunar sea with a diameter of 420 km.

The age is estimated at about 4 billion years. It is flooded with overcrowded lava, the depth of which reaches 3 km. Interesting craters on the southern side of the sea are the Vitello crater (pictured slightly below and to the right of the center), the central part of which resembles a podium on which the crater peak is located. And the almost completely destroyed Doppelmeir crater, with a central peak with smooth triangular sides.

Ancient crater, located slightly to the left and higher from the Clavius crater

The diameter is almost 150 km, the depth is 4.5 km. By nature, it resembles Clavius. The central slide is also shifted to the left of the center. Presumably, the bottom of the crater was also formed after the formation of the crater itself.

Unusual Lunar Formation. Many hypotheses about the artificial origin of this wall circulated on the Internet.

In fact, this is a tectonic fault on the Moon. The wall is 120 km long. Presumably the height of the wall is from 200 to 400 meters. It is best to observe the wall on the 8th or 22nd day of the Moon's rise.
Other objects in the picture: to the left of the wall you can see a crack in the form of a worm, about 50 km long, with rounded ends. The crack was most likely formed by lava flows. And the largest craters: Arzakhel on top, Phoebit double crater below and an ancient crater at the bottom of the photo - Purbakh.

9) Furrows of Hyginus and Ariadeus
Formations of mysterious origin - long grooves on the surface of the Moon, as well as chains of lunar craters. It is especially mysterious when the chains of lunar craters exactly coincide with the furrow, as seen in this photo.

The Ariadeus furrow (the right lane in the picture) is 250 km long. It is one of the most famous furrows on the visible part of the lunar surface. The origin of the furrow is not known. Presumably the result of lava flows.
Gigin's furrow, is on the left side of the photo. No less long furrow - 203 km in length. It is interesting that the chain of craters exactly coincided with the direction of the furrow itself. According to the theory of probability, such an event is negligible, or rather impossible to say. Not only are crater chains a rare and mysterious occurrence (can form from a comet's tail) so that the chain hits the furrow and turns in the same direction as the furrow, it really isn't explicable at this point.

A romantic haven on the moon. It's a pity, instead of the sea, dried and hardened lava.

It was originally a huge impact crater 250 km in diameter. Now the southeastern part of the bay is connected to the sea of rains. The edges of the rainbow bay form Cape Laplace in the north, 2.5 km high, and Cape Heraclides in the south, 1.3 km high. And the walls of the former crater are called Jura Mountains or Jura Mountains. The height of these mountains reaches three kilometers. The formation of the bay is commensurate with the formation of a sea of rains, this is approximately 3.5-4 billion years ago. However, off the coast of the bay there is an older magma that differs in color from the main frozen magma of the Sea of Rains, which may indicate an earlier origin of the Rainbow Bay. The bay is located in the northern hemisphere of the moon and is visible even with the naked eye. The Soviet Lunokhod 1 in 1970 and the Chinese lunar rover Chanye 3 in 2013 visited the bay.

11) Crater Plato and Alpine Valley
Photo of another interesting area of the lunar surface (by clicking the original 1214 pixels wide is available)

This site is interesting both for the Plato crater and for the mountain network of the lunar Alps.
The Plato Crater, with an age of almost 4 billion years, with a diameter of 100 km and a depth of 2 km, has a very flat bottom, flooded with magma. Not even a trace of the central hill of the crater remained, and its walls collapsed due to lava impact. It is surprising that large meteorites did not fall to the bottom of the crater in later periods. At 5000 mm, only a few small craters can be discerned in its area. From the north side of the crater, you can see the "Plato's furrow", reminiscent of a winding riverbed. Presumably, the meteorite that formed the crater fell into the mountain range, thereby completely destroying them.
The Alps and the Alpine Valley, which are to the right of Plato, form lunar mountains, dividing by a huge canyon. This canyon is the Alpine Valley.
The Alps are believed to have formed as a result of the fall of an asteroid. The highest mountain of the lunar Alps was named Mont Blanc, by analogy with the terrestrial Alps. On the moon, the height of Mont Blanc is more than three kilometers. And the entire mountain network is about 260 km long with an average height of 2.5 km. But the main attraction of the Alps is, of course, the Alpine Valley. This valley stretches for 160 km with an average width of 10 km. Scientists explain the formation of the valley as a graben, formed as a result of the subsidence of the lunar crust along a fault that arose during the formation of the Sea of Rains basin, and subsequently the depression was flooded with lava. At the bottom of the valley there is a narrow furrow no more than 1 km wide (in the photo, only the central part of this furrow was recorded), it stretches for almost 140 km.

12) North Pole of the Moon
The Moon's North Pole is completely covered with craters of various diameters.

But what's interesting about the North Pole? And the fact that NASA experts found frozen water, that is, ice, in 40 craters of the Moon's North Pole. There are no samples yet, and evidence of the existence of ice is based on analyzes of the LRO orbital station and the Russian LEND instrument, as well as the LCROSS and Chandrayan-1 stations.
The recognizable craters at the North Pole are Anaxagoras and Goldschmidt. The last one is an ancient ruined crater 115 km in size and 3.5 km deep. Anaxagoras is a relatively young crater, 1 billion years old, 50 km in size and three kilometers deep. In the photo, they are lower and to the left of the center, recognizable by the fact that the meteorite that formed Anaxagoras fell on the western wall of Goldschmidt.

13) Crater Herschel J. and Garpal
Two highly visible craters near the North Pole. They are located above the rainbow bay.

Crater Herschel J. (pictured on the right) almost collapsed and disappeared. Its walls are no longer as clear as those of young craters. Today, the crater is only 900 meters deep and 155 km in diameter.
Garpal Crater (pictured left) is a young impact crater. 40 km in diameter, 3.5 km deep. and the central slide is only 350 meters away.

14) Craters Archimedes, Autolycus and Aristilla
Three famous lunar craters.

The lowest crater in the photo is Archimedes. It is 3.5 billion years old, 81 km in diameter and 1.5 km deep. Located in the Sea of Rains. Like Plato crater, its bottom is filled with lava, and therefore is rather flat with a few small craters. Archimedes has a system of grooves, in the photograph you can see, as barely noticeable lines going north for more than 150 km.
The middle crater is Autolycus. 40 km in diameter and 3.5 km in depth. The age is estimated to be between 1 and 2 billion years.
The upper crater is Aristille. About the same age as Autolycus, slightly wider, about 55 km in diameter, and slightly shallower at 3.3 km.
An interesting detail of the image is the furrow system on the lower right side. These are the Headley furrows bordering the Apennine mountains. The furrow is 116 km long and about 1.2 km wide. with a depth of 300 meters. It is assumed that the furrow was formed as a result of underground lava flows followed by the collapse of the ceiling.

That's all. In conclusion, I want to show how these objects are located on the full moon for greater recognition:

a larger size is available by clicking. Full moon photo taken back in 2011

I really hope that now it will be even more interesting for you to look at the moon, especially on warm evenings and nights. And maybe you can share with someone about what you learned today :)

A little about the technical side of filming. All photographs were taken with a Celestron SCT 8 "mirrored lens with an aperture of 203 mm and aperture of f / 10. A focal length of 5000 mm was achieved using a Televue Powermate 2.5x telectender. Videos were recorded on a VAC-136 black and white camera in the infrared spectrum with an Astronomic IR filter. -pass 742.
Processing was carried out in programs:
1) frame stacking - AutoStakkert 2. Registax 6
2) fine-tuning (deconvolution and wavelets) - AstroImage 3 Pro
3) final color correction of the histogram - Photoshop CS
PS: why not single frames and not a "DSLR" can be read

State treasury

educational institution of the Kaluga region

"Kaluga secondary school - boarding school No. 5 named after

for students with disabilities "

How did craters form on the moon?

The work was done by students of grade 6 "a":

Leaders:

Kaluga, 2017

Introduction ................................................. ................................ 3

Chapter I. Theoretical part ............................................. .....5

Types of craters ... ............................................... .....................5

Impact craters ................................................ .....................5

Crater formation ... ... ... ............................................. 6

Chapter II. Practical part …………………………… ..... 10

Experiment................................................. ...........................ten

Main conclusions................................................ .................13

Used literature ………………………… .. …… 14

Introduction

Galileo Galilei pointed a telescope at the moon in 1609 and found that the moon's surface was not smooth. The moon has mountains, craters: the lunar surface is relief. Subsequent studies showed that “the lunar surface can be divided into two types: very old mountainous terrain (lunar continent) and relatively smooth and younger lunar seas. Lunar "seas", which make up approximately 16% of the entire surface of the Moon, are huge craters created by collisions with celestial bodies that were later flooded with liquid lava. "

Since the late 1780s, two main hypotheses have been put forward to explain the origin of craters - volcanic and meteoric.

According to the postulates of the volcanic theory put forward in the 80s of the 18th century by the German astronomer Johann Schroeter, lunar craters were formed as a result of powerful eruptions on the surface. But in 1824, the German astronomer Franz von Gruytuisen also formulated a meteorite theory, according to which, when a celestial body collides with the Moon, the surface of the satellite is pushed through and a crater is formed.

For a long time, supporters of the two theories of the origin of craters fiercely argued, but subsequent studies, and especially flights to the Earth's satellite since 1964, summed up this dispute about the origin of craters on the Moon: lunar craters were formed as a result of collisions with celestial bodies.

Purpose of work:

Check the correctness of the meteorite theory of the origin of craters. Find out how craters are formed, what determines the size and depth of craters.

Work tasks:

1. Study the types of craters and the principles of their formation.

2. Conduct an experiment, draw a conclusion from observations.

Working methods:

experimental and experimental.

Equipment:

flour, cocoa, objects of different sizes and volumes, a camera.

ITheoretical part

Crater types

The word "crater" has different meanings. This is the vessel, and the name of the constellation, and the name of the commander. But a crater also denotes a depression in the surface.

A crater is a landform, a depression in the surface of the earth or at the top of a mountain.

Craters can be volcanic, impact, erosive, explosive, lunar.

A volcanic crater is a depression at the summit or slope of a volcanic cone (see also: caldera).

Impact crater (meteorite crater) - a depression on the surface of a space body, the result of the fall of another smaller body.

An erosion crater is a depression of erosive origin.

Explosive funnel - a deepening in the ground from the explosion of a conventional or nuclear weapon. Lunar crater is a depression on the surface of the Moon.

Impact (lunar) craters

“A lunar crater is a bowl-shaped depression on the lunar surface, which has a relatively flat bottom and is surrounded by an annular raised wall. In accordance with modern concepts, the vast majority of lunar craters are impact craters. "

This definition of a lunar crater is given by modern science. A lunar crater is an impact crater. And an impact crater occurs as a result of the fall of smaller bodies onto the surface.

Space exploration has shown that impact craters are the most common geological structure in the solar system. Such formations are found not only on the moon, but also on Earth, Mercury, Mars.

Geological structure

The structure of craters is determined by the energy of collision of the meteorite with the surface (which, in turn, depends on the mass and velocity of the space body, the density of the atmosphere), the angle of encounter with the surface and the hardness of the substances that form the meteorite and the surface.

With a tangential impact, grooved craters of shallow depth appear with little destruction of the underlying rocks; such craters are quickly destroyed due to erosion. An example is the Rio Quarta crater field in Argentina, which is about 10 thousand years old: the largest crater in the field is 4.5 km long and 1.1 km wide at a depth of 7-8 m.

Structure of regular and large craters.

When the direction of collision is vertical, rounded craters appear, the structure of which depends on their diameter. Small craters (3-4 km in diameter) have a simple bowl-like shape, their funnel is surrounded by a wall formed by raised layers of underlying rocks (basement wall), covered with debris ejected from the crater (bulk wall, allogeneic breccia). Authigenic breccias, shattered and partially metamorphosed upon impact, lie under the bottom of the crater; fractured rocks are located under the breccia. The depth-to-diameter ratio of such craters is close to 1⁄3, which distinguishes them from volcanic crater-like structures, which have a depth-to-diameter ratio of about 0.4.

For large diameters, a central slide appears above the impact point (at the point of maximum compression of the rocks). With even larger crater diameters (more than 14-15 km), ring uplifts are formed. These structures are associated with ripple effects (like a drop falling on the surface of water). With an increase in diameter, craters quickly flatten: the depth / diameter ratio drops to 0.05-0.02.

The size of the crater may depend on the softness of the surface rock (the softer, the smaller the crater, as a rule).

On cosmic bodies that do not have a dense atmosphere, long "rays" (formed as a result of the ejection of matter at the moment of impact) can persist around the craters.

When a large meteorite falls into the sea, powerful tsunamis can occur (for example, the Yucatan meteorite, according to calculations, caused a tsunami 50-100 m high).

Meteorites weighing more than 1000 tons are practically not retained by the earth's atmosphere; lighter meteorites can be significantly slowed down and even completely evaporate without reaching the surface.

In old astroblems, the visible structure of the crater (hill and rampart) is often destroyed by erosion and buried under alluvial material, however, based on changes in the properties of the underlying and transported rocks, such structures are quite clearly determined by seismic and magnetic methods.

Crater formation

The average speed at which meteorites crash into the Earth's surface is about 20 km / s, and the maximum speed is about 70 km / s. Their kinetic energy exceeds the energy released during the detonation of conventional explosives of the same mass. The energy released during the fall of a meteorite weighing over 1,000 tons is comparable to the energy of a nuclear explosion. Meteorites of this mass fall to Earth quite rarely.

When a meteorite meets a solid surface, its movement slows down sharply, but the target rocks (the place where it fell), on the contrary, begin to accelerate under the influence of the shock wave. It diverges in all directions from the point of contact: it covers a hemispherical area under the surface of the planet, and also moves in the opposite direction along the meteorite itself (striker). Having reached its back surface, the wave is reflected and runs back. Stretching and compressing with such a double run usually completely destroys the meteorite. The shock wave creates colossal pressure - over 5 million atmospheres. Under its influence, the rocks of the target and the striker are strongly compressed, which leads to an explosive increase in temperature and pressure, as a result of which, in the vicinity of the collision, the rocks are heated and partially melted, and in the very center, where the temperature reaches 15,000 ° C, even evaporate. Solid fragments of the meteorite also fall into this melt. As a result, after cooling and solidification, a layer of impactite (from the English impact - "impact") is formed on the bottom of the crater - a rock with very unusual geochemical properties. In particular, it is very strongly enriched with chemical elements that are extremely rare on Earth, but more characteristic of meteorites - iridium, osmium, platinum, palladium. These are the so-called siderophilic elements, that is, belonging to the iron group (Greek σίδηρος).

With the instant evaporation of a part of the substance, plasma is formed, which leads to an explosion, in which the target rocks are scattered in all directions, and the bottom is pressed in. A round depression appears at the bottom of the crater with rather steep sides, but it exists for a fraction of a second - then the sides immediately begin to collapse and slide. On top of this mass of soil, a stone hail falls from the substance thrown up vertically and now returning to its place, but already in a crushed form. So at the bottom of the crater, breccia is formed - a layer of rock debris, cemented with the same material, but crushed to grains of sand and dust. Collision, compression of rocks and passage of a blast wave last tenths of a second. It takes an order of magnitude longer to form the crater cavity. And after a few minutes, the impact melt hidden under the breccia layer cools down and begins to solidify rapidly. This completes the formation of the crater.

In violent collisions, solid rocks behave like liquids. Complex wave hydrodynamic processes arise in them, one of the characteristic traces of which is the central hills in large craters. The process of their formation is similar to the appearance of a drop of recoil when a small object falls into the water. In large collisions, the force of the explosion is so great that the material ejected from the crater can even fly into space. This is how meteorites from the Moon and Mars came to Earth, dozens of which have been discovered in recent years.

The peak values of pressures and temperatures during a collision depend on the energy release, that is, the speed of a celestial body, while part of the released energy is converted into a mechanical form (shock wave), part - into thermal form (heating of rocks until they evaporate); the energy density decreases with distance from the center of impact. Accordingly, during the formation of an astrobleme with a diameter of 10 km in granite, the ratio of evaporated, molten and shattered material is approximately 1: 110: 100; During the formation of the astrobleme, there is a partial mixing of these transformed materials, which leads to a wide variety of rocks formed during impact metamorphism.

According to the international classification of impactites (International Union of Geological Sciences, 1994), impactites localized in the crater and its vicinity are divided into three groups (by composition, structure, and degree of impact metamorphism):

Impacted rocks - rocks of the target, poorly transformed by the shock wave and, thanks to this, retained their characteristic features;

Melted rocks are products of solidification of an impact melt;

Impact breccias are clastic rocks formed without or with very little impact melt.

Impact crater formation

IIPractical part

Experiment

Our group decided to experimentally test how craters are formed on the lunar surface. Is it true, as the theory claims, that craters on the surface are formed as a result of the collision of meteorites with the surface of the Moon?

To solve this problem, it is necessary to conduct an experiment. The basic idea is that we need a surface similar to the surface of the Moon, and solid objects that will act as meteorites. Thus, we will be able to simulate the processes occurring during the collision. Of course, it must be taken into account that when meteorites hit the earth's atmosphere, they heat up. But as far as we know, the Moon has no atmosphere, and, therefore, meteorites do not heat up when falling, and energy is released only when they collide with the surface of the Moon. We carry out the experiment on Earth in the presence of air, but it seems to us that the influence of air on the process is insignificant. Therefore, in our experiment, we do not take into account air resistance.

This experiment requires river sand, flour, cocoa powder, and objects of various sizes.

Flour must be poured into a tray on a tray, smooth the surface. Using a strainer, pour the cocoa powder over the entire surface of the flour. Next, you need to throw objects vertically or at an angle from different heights and with different initial speeds. In the second variant of the experiment, the flour must be poured onto the sand with a slide and the same actions as in the first case must be done.

The results of the experiment were photographed.

Main conclusions

According to the experiment, the following conclusions can be drawn:

· The size of the craters depends on the size of the falling bodies.

· The depth of the crater depends on the mass of the falling body, as well as on its speed.

· Well, we can give an affirmative answer to our question: craters on the Moon appear as a result of the collision of celestial bodies with the surface of the Moon. Lunar craters are impact craters.

Of course, it must be admitted that the experiment carried out provides an answer to general questions, and additional experiments must be carried out to clarify all the causes and mechanisms of crater formation.

References:

1. ru. wikipedia. org

2. cse. ssl. berkeley. edu

Scientists have found an explanation why craters on the visible side of the moon are deeper than on the opposite hemisphere

Scientists, analyzing the data of two spacecraft-twins of the NASA mission "GRAIL" (Gravity Recovery and Interior Laboratory), presented a new vision of how the features of the relief of the visible side of the Moon were formed. A report on the asymmetric distribution of lunar impact craters was published this week in the journal Science.

According to the chief researcher of "GRAIL" Maria Zuber of the Massachusetts Institute of Technology, from time immemorial, mankind has been interested in the mysterious nature of the natural satellite of the Earth. Zuber notes that at the moment, scientists know a lot about the structure and features of the relief of the moon, in particular, astronomers know that large dark spots visible through telescopes are in fact represented by huge impact craters filled with lava, which formed about 4 billion years back as a result of collisions with asteroids. According to Maria Zuber, data from the Ebb and Flow spacecraft, launched by NASA as part of the GRAIL program, indicate that the dark side of the moon, as well as its visible side, is "dotted" with huge impact craters. The attention of scientists was attracted by the fact that the structure and depth of craters on the dark lunar side is somewhat different, and this in turn indicates that the surface of the moon did not react in the same way to collisions with other celestial objects.

The most basic snag was that the impact craters on the visible side were radically different in size from the impact craters on the dark side of the Moon. Most of the largest craters on the visible side of the Moon are filled with lava flows that hide important landform clues that could be used to determine their size. The satellites of the GRAIL mission measured the inner structure of the Moon in unprecedented detail in just 9 months in 2012. Thanks to the information received, scientists were able to examine the impact craters of the Moon in as much detail as possible and compare their size and depth.

Maps of the thickness of the crust, compiled on the basis of data from the twin probes, showed that there are more large impact craters on the visible side of the Moon than on the opposite side, which is not illuminated by the Sun. How could this happen if both hemispheres are equally susceptible to the likelihood of collision? This is due to the fact that the mantle and other rocks of the moon in the distant past were much hotter on the hemisphere facing our planet than on the dark side of the moon.

Scientists have long suspected that the temperature of the visible hemisphere of the moon was higher than that of the opposite side. They came to this conclusion judging by the presence on the surface of the visible side of the Moon of uranium and thorium, which is part of igneous rocks and specific mineral composition.

As explained by Katarina Miljkovic of the Institut de Physique du Globe de Paris. Collision modeling, who co-authored a published paper, indicates that even a slight increase in crustal and mantle temperature would cause an impact crater to roughly double in depth, compared to a similar "collision" with the moon's cold dark side.

It is the difference in temperatures between rocks and the surface of the Moon in the distant past that explains why impact craters on the visible side of the Moon are abnormally deep.

The new study, based on the GRAIL data, is also helping to revise the intensity of the last asteroid "bombardment" that the planets of the solar system experienced about 4 billion years ago.