The largest sea on the moon. Lunar seas - what is it? The seas on the moon - what a phenomenon

When asked if there is water on the Moon, scientists unanimously answered in the affirmative. But it is paradoxical that it is not in any of the seas on the Earth's satellite.

Briefly about the satellite of the Earth

The earth in the formative stage was molten, fire-breathing matter.

According to the main scientific hypothesis Giant Impact, 4.5 billion years ago, our planet collided with a similar celestial body the size of Mars.

The core of the object and part of the mass of our planet were thrown by inertia into low Earth orbit. From this gradually cooling matter, the Moon was formed, which became the satellite of the Earth.

Interesting figures about the Moon:

406,700 km - the distance that a spacecraft needs to overcome in order to reach the Moon when it is at its apogee;
356400 km - the distance separating the Earth and the satellite at perigee;
2681 km/h is the orbital speed of the satellite;
27.3 days - the duration of 1 revolution around the Earth, the so-called. sidereal month;
1.3 seconds is the time it takes moonlight to reach the surface of our planet;
3476 km - the diameter of the Moon (for comparison: the diameter of the Earth - 12753 km);
7.35x10²² kg - the mass of the satellite (80 times less than the earth);
-170…-180°С and +120…+130°С — night and day surface temperatures.

Dark rounded spots are clearly visible on the satellite disk. Even G. Galileo suggested that these are giant depressions filled with water.

In 1652, other scientists, G. Riccioli and F. Grimaldi, compiled a map on which the contours of the lunar seas were first drawn.

Much later, scientists found that there is no water in these depressions, dark due to the predominance of titanium and iron in the soil. The entire surface of the Moon is solid land. However, humanity has become so accustomed to the concept of "sea" that it has remained unchanged.

There is still water on the earth's satellite, but it is hidden in the structure of volcanic rock.

According to the latest theory about the source of water, it was brought to the Earth and the Moon by meteorites.

According to another version, as a result of the collision of the Earth with a cosmic body, part of the moisture did not evaporate, but became part of the soil of the formed satellite of the Earth.

moon seas

Their dimensions are amazing - up to 1100 km in diameter. This type of lunar landscape is characterized by a relatively flat bottom covered with a layer of solidified lava. Small elevations can be found on its surface.

There are many seas on the visible side of the Moon. Their names are mostly figurative.

These are the seas:

Humidity;
waves;
Eastern;
Humboldt;
rainy;
snakes;
Abundance;
Regional;
Crises;
Nectar;
clouds;
Islands;
Steam;
foam;
Known;
Smith;
Tranquility;
cold;
Southern;
Clarity.

On the invisible side of the Moon there are only 2 small seas: Dreams and Moscow. For this reason, the surface of the satellite is lighter here, and its reverse side is brighter than the visible one.

From the history of the study of the lunar seas:

The Known Sea got its name due to the fact that the Ranger-7 research apparatus landed here, which captured the details of the landscape of the earth's satellite (1964).
The Sea of Tranquility was first visited by a man - the astronaut of the Apollo 11 spacecraft N. Armstrong (1969).
The module of the Apollo 12 spacecraft landed in the Ocean of Storms. Astronauts A. Bean and C. Conrad took samples of lunar minerals (1969).
Soil samples from the Sea of Plenty were brought to Earth by the Luna-16 research probe (1970).
The region of the Sea of Clarity was first examined by the Lunokhod-2 spacecraft (1973).

Map of the visible side of the Moon with the designations on it of the seas, craters and lunar mountains. Credit: starcatalog.ru.

How did they appear

Since the earth's satellite has no atmosphere, it is defenseless against numerous meteorites arriving from space.

During the period of formation, when the soft crust of the Moon was still thin, after the impacts of celestial bodies, giant dents and gaps appeared on its surface.

Streams of red-hot magma poured out to the surface through the opened cracks from the bowels of the satellite. Gradually, it solidified, forming heavy basalt deposits in these places.

As they accumulated, there was an overweight of the satellite's masses, and its center of gravity shifted sharply. The moon turned out to be the heavier part facing our planet.

The influence of the force of gravity of the Earth also affected. Since then, only one side of it has been visible - with waterless seas. They occupy about 16% of the entire lunar landscape.

The reverse side of the satellite looks different. Despite the fact that both hemispheres were subjected to cosmic attacks of the same intensity 4 billion years ago, only 2 seas formed on the invisible side.

According to the version of American astronomers, in those days, volcanic activity and temperature on the visible side of the satellite were significantly higher. Therefore, the soft and thin crust was more easily penetrated by meteorites.

An image of the East Sea taken during its exploration during the Gravity Recovery and Interior Laboratory (GRAIL) mission.
Credit: GRAIL/NASA.

The largest sea on the moon

It is so large that astronomer G. Riccioli gave it the name Ocean of Storms. The irregularly shaped depression is located in the western part of the visible side of the satellite and extends for 2000 (according to other sources - for 2500) km.

This ocean on the moon is different from its other seas the absence of a mascon (mass concentration) - a gravitational anomaly.

According to scientists, this feature arose due to the fact that the ocean avoided meteor showers. Most likely, basaltic magma filled a space of 4 million km², pouring out from many neighboring holes.

Origin of the seas and oceans of the moon

Planetary scientists from Ohio State University (OSU) have explained the origin of the most visible features of the moon's landscape - "seas" and "oceans". Scientists believe that they arose in a collision with an asteroid that crashed into the moon from the opposite side. According to new research, an extremely large object once hit the invisible side of the moon and was able to send a shock wave even through the lunar core to the side of the moon that faces the Earth. The lunar crust there "peeled off" and "burst" in places - and now the Moon has characteristic scars from that long-standing cataclysm. This discovery is of great importance for the future exploration of lunar minerals, and besides, all this will probably help solve some terrestrial geological mysteries associated with the impact on the Earth of collisions with large celestial bodies. Already the first flights of the Soviet lunar stations and the American Apollos showed that the shape of the Moon is far from being an ideal sphere. And the most significant deviations from this sphere are observed in two places at once, and the bulge on the side that always faces the Earth corresponds to a dent on the invisible side of the Moon. However, for a long time it was believed that these surface features are caused only by the influence of Earth's gravity, which "stretched" this hump from the Moon at the dawn of its existence, when the lunar surface was molten and plastic.
Now, Laramie Potts and geology professor Ralph von Frese of Ohio State University have been able to explain these features as ancient asteroid impacts. Potts and von Frese came to this conclusion after studying the data on variations in the gravitational field of the Moon (which in principle allows you to display a map of the lunar "innards" and find indications of the concentration of minerals useful to humans) obtained using NASA's Clementine satellites. " (Clementine, DSPSE) and "Lunar Scout" (Lunar Prospector). It was expected that the material displacements caused by powerful collisions with large celestial bodies with the absorption of the impact energy (these places correspond to huge impact craters on the surface) could also be traced in layers located below the lunar crust, at the level of the mantle (that is, in a vast layer separating the metallic lunar core from its thin outer crust), but no more. However, it turned out that the extensive dents not only correspond to the same bulges on the opposite side of the Moon, but, moreover, there are similar protrusions in the mantle layer - as if squeezed out by some powerful blow coming directly from the lunar interior. It is possible in this way to track the path of shock waves that acted on the lunar interior in a certain selected direction.
Under the lunar surface, where the alleged collision took place, a "concave region" was found, where the mantle deepens into the core. The "dent" in the core is located 700 kilometers below the surface. - Scientists say they did not expect to see traces of the "cosmic catastrophe" so deep. From this it follows that the molten layer could not extinguish the powerful impact of the asteroid - and the wave spread further deep into the moon. Potts and von Frese believe that all the key events that determined the current pattern of the lunar "seas" occurred about 4 billion years ago, during the period when our Moon was still geologically active - its core and mantle were then liquid and filled with flowing magma. . The Moon at that time was located much closer to the Earth than it is now (later it gradually moved away due to tidal interactions), so the gravitational interactions between these celestial bodies were especially strong. When magma was released from the depths of the Moon by collisions with asteroids and created a kind of vast "hill", the earth's gravity seemed to "catch" it and did not release it from its embrace until everything solidified there. So the warped surface on the visible and invisible sides of the Moon and the characteristic internal features that connect the depression and the ledge are a direct legacy of those ancient times that the Moon has never been able to heal. Strange dark valleys - "seas" on the lunar side visible from the Earth are explained by magma that has flowed out to the surface, and so forever and frozen (this is a "frozen ocean of magma", in the words of von Frese). How exactly such vast volumes of magma managed to find their way to the lunar surface remains unclear, but scientists suggest that those powerful cataclysms discussed above may have provoked the appearance of a geological "hot spot" - the concentration of magma bubbles near the surface. After some time, some of the magma contained there under pressure was able to seep through cracks in the crust.

The lunar seas on the Moon have nothing to do with what the word “sea” means in our understanding, they are waterless. So what are the seas on the moon? Who gave them such interesting names? The lunar seas are dark, even and rather large areas of the lunar surface visible to us from the Earth, a kind of pits.

The seas on the moon - what kind of phenomenon?

Medieval astronomers, who first saw these areas on the Moon, suggested that they were just seas filled with water. In the future, these areas were called quite romantically: the Sea of Tranquility, the Sea of Abundance, the Sea of Rains, etc. As it turned out in reality, the lunar seas and oceans are lowlands, plains. They were formed by flows of solidified lava, pouring out of the crevices of the lunar crust, which appeared as a result of its attack by meteorites. Due to the fact that the solidified lava has a darker color than the rest of the surface of the Moon, the lunar seas are visible from Earth precisely in the form of extensive dark spots.

Ocean of Storms

The largest lunar sea bearing Storms has a length of more than 2,000 kilometers, and in total, amazing depressions occupy about 16% of the satellite's surface. This is the most extensive lava spill on the Moon. It is unusual that it does not, that is, it suggests the assumption that cosmic strikes did not fall on it. And, perhaps, lava simply flowed from neighboring dents.

Further clockwise, three clearly visible rounded seas open up to us - Rains, Clarity and Tranquility. All copyrights to these names belong to Riccioli and Grimaldi, presumably people with a very difficult character.

Features of the Sea of Rains

The Lunar Sea of Rains is the most terrible scar on the face of the Moon. According to some known data, this point was hit more than once: by asteroids and even, it is quite likely that by the nucleus of the comet itself. The first time was about 3.8 billion years ago. Lava poured out from there in several splashes, which were enough to form an ocean of Storms. "Mosquito baldness" in the Sea of Rains is rather immodest, but just opposite, on the reverse side of the lunar surface, Van der Graaff crater bulged out with a shock wave. At this point in time, somewhere in the Sea of Rains, the Chinese Jade Hare (lunar rover Yutu) has gone into the unmanifested, which has already completed its mission in the winter of 2013-2014 and now fell into its last sleep, occasionally, once every few months, modestly snoring to the delight of earthly radio amateurs.

Sea of Clarity

It has a shock origin and also with a mascon, almost as good as the previous one. Of all the lunar dents, these are the two most powerful. In the eastern part of this sea, the legendary Soviet Lunokhod-2 froze. He unsuccessfully drowned in a system of nested craters, after which he was covered with lunar dust and stuck. But, in spite of everything, he selflessly crawled along this sea for four whole months in 1973. But in the Sea of Tranquility, there are no gravitational anomalies. It does not have a percussive origin. Presumably, its formation is a consequence of the flow from the Sea of Clarity. Its fame is explained by the event that in the summer of 1969 the American Apollo 11 landed there, from which the first man on the moon, Neil Armstrong, came out, who uttered the catchphrase about a small step and a giant leap.

Sea of Plenty

Further, our attention is presented to another unstressed lunar sea - Abundance. It has a small, but rather strange It seems that the lowland has been present there since very ancient times, but lava flowed billions of years later. Where is unclear. This sea is known for the fact that in 1970 the Soviet "Luna-16" scooped up soil there and delivered it to Earth. That's "abundance" for you. To the north and south of the Sea of Plenty are two more seas - dents with quite clear gravitational anomalies. To the north is the Sea of Crises, to the south is the Sea of Nectar.

In general, these names are the fruit of the fantasy of intricate Italians. However, it is not clear how to explain the fact that two of our lunar stations crashed and crashed in the Sea of Crises. Our third station, it should be noted, successfully mined soil there and returned home. And no one had more desire to appear there from the Earth. And for the "nectar" they never tried at all.

The Sea of Nectar is one of the earliest seas of the Moon. He is predicted to be seventy million years older than the Sea of Rains. And there are only three large lunar seas left, they are located in a triangle to the south-west of the center of the lunar disk - these are the seas of Clouds, Humidity and the Known (emphasis on "a").

The Seas of Clouds and the Known are non-impact formations and are included in the general system of the Ocean of Storms. The Sea of Humidity is located somewhat on the outskirts and has its own very extensive mascon. The Sea of Clouds is of interest because it was formed much later in a place where there were many craters earlier. When lava poured over all the lowlands, this area was flooded along with ancient craters. But they are still visible to us, the very edges, in the form of numerous ring low hills. Of course, they are visible only in a normal telescope, pseudo-equipment will not show this. In addition to everything, there is one interesting object in the Sea of Clouds - the Straight Wall. It is a break in the lunar crust in the form of a height difference on flat terrain, which runs in an almost straight line of 120 kilometers, its height is about 300 meters.

In September 2013, a meteorite the size of a car accidentally hit this sea, exploding spectacularly. Spanish astronomers, who recorded this event, claim that this is the largest lunar meteorite of all that it seemed to mankind to see. There is still a lot of garbage walking on the Moon from the main one between Mars and Jupiter. At various times, many observers talked about some exciting and mysterious "sparks" on the surface of the moon - that's exactly what it is. The Moisture Sea Mascon is ideal for exploring. Throughout 2012, two NASA probes flew around the Moon, engaged in specific gravimetry (the GRAIL program), thanks to which a more or less clear map of all the gravitational anomalies of the Moon was compiled, and photos of the lunar seas were also taken. But nothing is known about the origin and history of occurrence there, there are no samples from there.

But the name of the last sea from our list - the Known - appeared in 1964. It is not the Italians who have tried, but the International Space Committee. It got its name because it gave a sufficient number of successful launches for all lunar programs and deliveries of soil samples.

Why don't the moon seas disappear?

A natural question arises: "Why did the Moon suffer so much? And why is it all beaten up in such a strange mystical way, while the Earth is unharmed and very beautiful?" Was Luna hired to work part-time as some kind of space shield? Far from it. The moon is not a shield for our planet. And the space debris flying into both of them is more or less evenly distributed. And, most likely, even more into the Earth - it is larger. It's just that the Moon doesn't have the ability to heal wounds. For four and a half billion years of its history, it has retained the traces of almost all the blows that were inflicted on it from space. There is nothing to heal them - there is no and no water to have erosion and smoothing; there is no vegetation to close faults and craters. The only effect on the moon is solar radiation. Thanks to her, the light scars of impact craters darken over the centuries, that's all. The soil of the Moon is everywhere - regolith. This is basalt rock ground into a kind of powder with an unthinkably exhausting threshing machine (Neil Armstrong once said that regolith smells of burning and shot caps). And the Earth immediately tightens and overgrows all combat wounds. And compared to the moon, this happens quite lightning fast. Small pits disappear without a trace, and large impact craters, of course, leave their mark, but they strongly sink and overgrow. And there are enough scars on our planet.

The seas on the moon look like real ones, because they are darker than the rest of the surface. However, the lunar seas do not contain a drop of water, they are just appearances and stereotypes of our thinking.

It is difficult to say what the ancient people thought when they looked at the dark spots on the lunar surface. But medieval astronomers asked this question and decided that these were the real seas. After all, they are much darker than the rest of the lunar surface, and therefore must be filled with something special. And since there are only two types of surface on Earth - land and sea, the logical conclusion was made that the Moon also has light land and darker seas. Moreover, some of these seas are located separately, like real ones.

The sea was first depicted on lunar maps in 1652 by the Italian astronomer Giovanni Riccioli and the Italian physicist Francesco Grimaldi. Since then they have been called that. The same two active comrades gave names to many lunar seas and they are still used today.

The reality, as usual, turned out to be quite different. The lunar seas were not what they were called.

Dark spots on the Moon = - these are the lunar seas.

The lunar seas are lowlands filled with solidified lava. Therefore, they have a gray-brown color, different from the lighter "mainland" areas. Their age is from 3 to 4 billion years, that is, less than the rest of the lunar surface. This can explain the much smaller number of craters on the "sea" surfaces.

There is a version that the seas on the Moon were formed due to the impacts of large meteorites. Because of this, powerful eruptions occurred, and lava flooded everything for hundreds and thousands of kilometers around. After all, the Moon was not always such a dead world as we see now. Once its bowels were red-hot, and the seething magma found its way out through any more or less large fault.

In some seas there are rare mountains. These are the peaks of high mountain ranges that were once located in this place, but were filled with lava. The highest ones stick out there now, towering above the “sea” surface, but since there are few of them, they are not often found, and the seas look more or less even.

Most of the lunar seas are concentrated on the visible side of the Moon, and on the back there are only a couple of them, and even then they are small - the East Sea and the Moscow Sea. There is a theory that due to the greater mass of basalt rocks that were formed from the solidified lava, the heavier and more abundant sea side of the Moon simply gradually turned towards the Earth and was fixed like that. After all, the Earth has a powerful tidal effect on the Moon, and it is natural that its more massive side turned out to be turned towards the Earth.

Therefore, it is not at all a fact that the seas on the Moon formed precisely on the visible side of the Moon. It is likely that billions of years ago it was just the other side, which was subjected to powerful bombardment by large meteorites arriving from outside the earth's orbit. This led to the appearance of the seas, and at the same time the Moon acted as a shield in front of our planet, taking on these blows.

By the way, rounded formations along the edges of the lunar seas are called bays. There are also lakes and swamps - small formations that cannot be called seas. Thus, there are the Bay of Fidelity, the Bay, Luck, the Lake of Spring, the Lakes of Joy and Death, the Swamp of Rotting, Sleep and Epidemics.

What seas are on the moon

In total, on the visible side of the Moon there is one ocean - the Ocean of Storms, and 20 seas:

Sea of Humidity.
East Sea.
Sea of Waves.
Humboldt Sea.
Sea of Serpents.
Sea of Abundance.
Regional Sea.
Sea of Nectar.
Sea of Clouds.
Sea of Islands.
Sea of Vapors.
Sea of Foam.
Sea Known.
Smith Sea.
Sea of Tranquility.
Sea of Cold.
Sea South.

All of them can be found on this diagram.

The location of the lunar seas.

For a detailed study, we recommend downloading the Atlas of the Moon, where all the seas, bays, mountain ranges and craters are signed on a large scale on a real photograph. There are several variants of the map - upright and inverted, for binoculars and telescope observations, as well as in the negative for easy printing on a b/w printer. In a zip archive so you can open it without downloading. The volume is 90 MB, because the maps are large, they can be greatly enlarged and conveniently view any area of the Moon with captions on a large screen.

Consider several lunar seas in more detail.

Ocean of Storms - the largest sea on the moon

When you look at the Moon, you will notice the largest dark spot on its left side, almost along the equator. This is the Ocean of Storms - the largest lunar sea. From south to north, its diameter reaches 2500 km, and the total area is about 4 million square kilometers - this is slightly less than the area of Europe, except for Russia. The total area of the Ocean of Storms is 16% of the area of the entire lunar surface.

The surface of the Ocean of Storms, like all lunar seas, consists of basalt - hardened lava.

To the northeast of the Ocean of Storms is the Sea of Islands and the mountain range - the Carpathians. To the southeast is the Known Sea, where the American Ranger-7 probe landed in 1964. To the south is the Sea of Humidity. To the north you can find the Sea of Rains. All these seas are part of the Ocean of Storms.

By the way, on November 19, 1969, the landing of the Apollo 12 lunar module took place just in the region of the Ocean of Storms, 370 km south of the Copernicus crater. From there, 34 kg of rock samples were delivered.

The crater Copernicus in the Ocean of Storms, 96 km in diameter, is perfectly visible through binoculars.

The crater Copernicus is the most notable sight of the Ocean of Storms. It is located closer to the eastern coast of this ocean and is perfectly visible through binoculars. Very abundant and extended bright rays radiate from it from the rock ejected during the fall of the meteorite. The Copernicus crater is 96 km in diameter and 3.8 km deep.

Sea of Rains

In the north of the Ocean of Storms, you can see the vast Sea of Rains. This is the result of the fall of a large meteorite or even a comet about 3.85 billion years ago. However, the undulating surface suggests that the Sea of Rains was filled with lava several times, so that several cataclysms occurred here with huge lava eruptions. There was so much of it that it filled both the Ocean of Storms and the Sea of Clouds, located to the south.

The Sea of Rains is the largest among all those having a shock origin. Its diameter reaches 1123 km, and its depth is 5 km. The height difference between the surface of the sea and the mountains along its edge reaches 12 km.

One of the impacts of the meteorite in this area was so strong that seismic waves traveled through the entire Moon, forming a chaotic region on the far side with mountain ranges and Van de Graaff crater. At a distance of up to 800 km from the Sea of Rains, rocks thrown out during this impact are scattered in abundance.

The Soviet Lunokhod-1, delivered to the Moon in 1970, successfully worked for 10.5 months in the Sea of Rains. The Chinese "Jade Hare", launched in 2013 and lost the ability to move, also worked in the Sea of Rains. These two devices are still there.

The legendary Soviet Lunokhod-1 worked in the Sea of Rains for 10.5 months.

Also in the area of the Sea of \u200b\u200bRains lies the pennant of the USSR, delivered there by the Soviet automatic station Luna-2. This station was the first in the world to reach the surface of our natural satellite - it was September 13, 1959, 60 years ago. And in the Sea of Rains, in the Swamp of Decay, the American astronauts of the Apollo 15 mission landed.

And here the Sea of Rains was trampled by the astronauts of the Apollo 15 mission.

This lunar sea is located east of the Sea of Rains - they are separated by the mountain ranges of the Apennines and the Caucasus. This is also the result of the fall of a large meteorite, but the Sea of Clarity is much smaller than the previous one - its diameter reaches 700 km.

Sea of Clarity on the Moon.

The Sea of Clarity is interesting because the basalt in it is more diverse in color. And in its center, a mascon was found - an area of \u200b\u200bpositive gravitational anomaly. In this place, gravity is increased compared to other regions.

In the Sea of Clarity in 1974, the Soviet Lunokhod-2 worked for 4 months. It was also visited by the astronauts of the Apollo 17 mission.

Landscapes of the Sea of Clarity taken by the Apollo 17 astronauts

There are very few craters in the Sea of Clarity. The most noticeable and largest is the Bessel crater, with a diameter of 16 km.

This sea is very noticeable, although it is relatively small - its diameter is 556 km. It is located in the eastern part of the lunar disk, above the equator and, as it were, apart. This is a very ancient formation, perhaps its age is 4.55 billion years, that is, comparable to the age of the Earth and slightly less than the age of the Moon itself.

The Sea of Crises has a very flat surface, and in its southern part, very ancient craters, partially filled with lava, are clearly visible through a telescope.

In the Sea of Crises, the Soviet stations Luna-15 and Luna-23 crashed, and Luna-24 successfully took and delivered soil samples to Earth in 1976.

Lunar seas are interesting objects. We see them all the time on the moon. But we do not think that these are the results of terrible cataclysms that took place on the Moon billions of years ago. Any of them, if it happened on our planet, would be the end of all life. Maybe the Moon became the shield that took on these terrible blows, and thanks to which we exist.

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