The moons of Mars are Phobos and Deimos. A mysterious monolith on the surface of the Martian moon Phobos (4 photos). Interesting facts about Phobos and Deimos

Mars, Earth's red neighbor, is often the focus of astronomers' attention. Proximity makes it an achievable goal space flights and research. Today it is one of the most studied planets solar system.

For a long time, the satellites of the Red Planet remained hidden from view. According to stories, astronomer Asaph Hall, who tried in vain to discover them, wanted to give up everything, and continued his work only at the insistence of his wife. The very next night after resuming the search, he discovered the satellite of Mars, Deimos, and a few days later, Phobos.

Assumptions

As you know, the Red Planet is named after the Roman god of war. To match her, Phobos and Deimos, the satellites of Mars, received the names of his sons. “Fear” and “horror”, which is what the names of these cosmic bodies, did not generate corresponding emotions among scientists. Rather, they caused confusion. The measurement results showed that the weight of the objects was too light despite their rather impressive dimensions. There was even an opinion that satellites were hollow inside, which means they had artificial origin. Such assumptions were refuted after the first images of Phobos and Deimos from spacecraft appeared.

The smallest

Both satellites of Mars turned out to be rather small space objects. The images clearly show the slightly elongated ellipsoidal shape that is characteristic of them. The data obtained made it possible to assign the satellites of the Red Planet the title of the smallest similar objects in the entire solar system.

Phobos is a satellite of Mars, slightly exceeding its “brother” in its parameters. It is located closer to the planet. Both objects, like the Moon, always face Mars with the same side. They are extremely difficult to view from Earth; this can only be done with a powerful telescope. The reason for this state of affairs lies in the composition of the satellites: it is dominated by carbon mixed with ice. Deimos and Phobos reflect a very small percentage of light rays and, as a result, appear as very dim objects. This same composition, which greatly distinguishes the satellites from Mars, suggests that Phobos and Deimos were once asteroids captured over time by the Red Planet.

The closest satellite of the planet Mars

Phobos, as already mentioned, is the larger of the pair of “closers” of the Red Planet. The distance that separates it from Mars is estimated at 6 thousand kilometers, which makes it the closest satellite of all known today. This situation has certain consequences: Phobos is a satellite of Mars, which in about 50 million years will fall on the planet, or will be torn into pieces and turn into a ring of asteroids. This version of the fate of the cosmic body is supported by its gradual decline towards the surface of Mars. The distance between two objects decreases by 1.8 m every hundred years.

Phobos orbits Mars in 7 hours and 39 minutes. The speed allows the satellite to outpace the daily rotation of the Red Planet. As a result, Phobos moves for an observer on Mars, appearing over the horizon in the west and setting in the east.

Consequences of the collision

A characteristic feature of both satellites is their surface riddled with craters. The largest of them is located on Phobos, named after the wife of the discoverer of satellites. The diameter of the Stickney crater is 10 km. For comparison: Phobos itself has dimensions of 26.8 × 22.4 × 18.4 km. Presumably, the crater was the result strong blow when a cosmic object or collision falls on the surface of Phobos.

Near the crater there are mysterious grooves or cracks. They are a system of parallel recesses. The furrows extend for 100-200 km at a depth of 10-20 km, the distance between neighboring ones reaches 30 km. The reason for their occurrence is not completely clear. The version that is most consistent with all the data obtained is that the grooves were formed after material that exploded on the Red Planet fell onto the Martian satellite. Scientists, however, are in no hurry to call this hypothesis the only correct one: research continues.

Second son of the god of war

Deimos is a satellite of Mars with parameters of 15x12x11 km. It is located further than Phobos and makes one revolution around the Red Planet in just over 30 hours. Deimos is 23 thousand kilometers away from the center of Mars.

Scientists were able to see Deimos for the first time after receiving a photograph taken by the Viking 1 spacecraft in 1977. An image taken by its "successor" called Viking 2 showed that Mars' smaller moon also couldn't boast smooth surface. True, unlike Phobos, it is not decorated with furrows, but with massive blocks, the sizes of which are estimated to range from 10 to 30 km.

Versions

Today there is no consensus on the origin of Deimos and Phobos. Most astronomers adhere to the point of view stated above that they were once asteroids. Existing data on their composition speaks in favor of this hypothesis: in this parameter, the satellites are related to asteroids associated with Jupiter. Presumably, the gas giant, with its gravitational force, influenced the orbits of two cosmic bodies in such a way that they approached Mars and were captured by it.

Some scientists, however, adhere to an alternative point of view. They talk about the contradiction of the existing hypothesis to the laws of physics and put forward their own theory. According to her, Phobos and Deimos were never classified as asteroids. They were parts only satellite Mars, torn to pieces by the gravity of the Red Planet. The most massive and largest part was pulled closer to the surface and was named Phobos, while the less impressive and lighter part began to circulate in a distant orbit and turned into Deimos. According to astronomers who adhere to this version, evidence of it can be obtained after more detailed study soil composition on the two moons of Mars.

Astronomers' plans

The moons are a great place to observe Mars. Astronomers plan to organize on them something like a base, from which, with the help of robots, more information can be compiled detailed map Mars. It is easier to obtain almost any information about the planet from a satellite. Of course, the greatest hopes in this sense rest on Deimos, which does not face such a sad fate as Phobos.

Both satellites orbiting the Red Planet have not yet told people everything about themselves, just like Mars itself. However, the relatively close location to Earth allows us to hope for the speedy satisfaction of scientists' curiosity. However, we cannot guarantee this with all certainty: for every answer found, space is capable of offering a hundred more questions.

Mars has two satellites, they are called Phobos and Deimos. Both were discovered in 1877 by American astronomer Asaph Hall. This discovery was made at the US Naval Observatory in Washington, DC. The astronomer saw Deimos on August 12 at 7:48 am GMT, and he discovered Phobos on August 18 at 9:14 am GMT. Thus, the red planet officially acquired satellites.

Phobos is translated from ancient Greek as “fear”, and Deimos as “horror”. Why were these cosmic bodies called that? By analogy with the god of war, Mars. According to ancient greek mythology he had two sons - Deimos and Phobos. They accompanied their father everywhere and instilled horror and fear in the hearts of people. And so astronomers decided to turn the ancient myths into reality. Thus, they paid tribute to Ancient Greece.

The satellites are small in size. Each of them rotates in its own orbit, with Phobos in a closer orbit to Mars, and Deimos in a farther orbit. The orbits of these cosmic bodies are almost circular. From Phobos to Mars the distance is 6 thousand km. This is much closer than any other known planetary moon in the solar system. The distance from Deimos to Mars is 23,460 km.

The satellites of Mars always face the same side towards it, since they rotate around their axes with the same period as around the red planet. These objects have an irregular shape, that is, different from round. They look like dark rocky formations and resemble asteroids.

Phobos

The dimensions of this Martian moon are 27 km × 22 km × 18 km, and the mass is 1.0659 × 10 16 kg. With such a small mass, the satellite could not receive o round shape under the influence of its own gravity. Accordingly, there is no atmosphere, and gravity is extremely low. This cosmic body has an albedo of 0.071. This indicates weak reflection sunlight from the surface.

The porous surface has low density. It is assumed that the satellite contains a large number of ice. There are many craters on it. The largest of them is called Stickney in honor of Asaph Hol's wife Angelina Stickney. Its diameter is more than 9 km, and the crater occupies a significant proportion of the satellite's area.

There are parallel grooves on the surface near Stickney. Their depth reaches 30 m, and their width is 100-200 m. It is assumed that these are crater chains formed in different periods time. The reason for their occurrence was meteorite impacts, as a result of which rocks of the satellite were thrown into space.

The orbital period around Mars is 7 hours 30 minutes. The semi-minor axis of the orbit is 9377 km. Experts say that the orbit of Phobos has a tendency to decrease (tidal braking). Every 100 years, the satellite approaches the surface of the red planet by 1.8 meters. In 43 million years, this Martian moon will fall on the main cosmic body, but before that it will collapse into many pieces.

An interesting hypothesis was put forward by the Soviet astrophysicist Joseph Samuilovich Shklovsky in 1958. Studying the orbital motion of Phobos, he assumed that the satellite was empty inside. That is, this space object is of artificial origin. According to calculations, it was a hollow iron ball with a wall thickness of no more than 6 cm.

However, subsequently errors were discovered in Shklovsky’s calculations. And precise measurements of the orbit were carried out in 1969. Spacecraft measured the density of Phobos. It is equal to 1.887 g/cubic cm. The satellite is a cosmic debris of natural origin and there is nothing artificial in it. At the same time, it contains voids (approximately 30%) and is not a solid piece of rock.

Deimos

As already mentioned, the satellites of Mars are 2 cosmic bodies, and the farthest of them in relation to the red planet is Deimos. Its dimensions are 15 km × 12.2 km × 11 km, and its mass is 1.4762 × 10 15 kg. The average radius is 6.2 km. This satellite makes a full revolution around Mars in 30 hours and 17 minutes. The semi-minor axis of the orbit is 23463 km. Deimos' orbit is slowly increasing, and the red planet will lose its second moon in the distant future.

The shape of the satellite is highly non-spherical. It consists of rock rich in carbonaceous material. There are few craters on the surface. This is explained by the partial filling of impact dents with regolith. The density of the latter is high and equal to 1.471 g / cubic meter. see. The two largest craters are named Swift and Voltaire. They are named after famous writers, which suggested that Mars had two moons long before their discovery.

If you stand on Mars, you can see Deimos, which regularly passes in front of the Sun. But it is so small that it cannot cause full eclipse. It appears in the form of a small blackhead crossing the solar disk. This spectacle was photographed twice by landers operating on the red planet. The albedo of this satellite is 0.068.

Origin of the moons of Mars

It is unknown how the satellites of Mars appeared. There are many hypotheses, and they are all extremely contradictory. The main hypotheses state that Deimos and Phobos became satellites as a result of asteroid capture or accretion. During asteroid capture, the asteroid enters the orbit of a large planetary body and becomes its satellite. Accretion refers to the accumulation of particles in a massive object through gravitational attraction. There is also an assumption that 2 asteroids hit Martian orbit from the asteroid belt.

In addition, there is a theory about a binary asteroid. This is when 2 asteroids orbit around a common barycenter. Once within the range of Mars, they were torn apart by tidal forces, and each of them began to revolve around the red planet in its own orbit. There are other scientific assumptions related to theories of planet formation (planetesimal hypotheses). They all look very attractive and convincing, but no one knows the real truth.

Vladislav Ivanov

MOSCOW, July 21 - RIA Novosti. The orbiting Hubble Observatory accidentally received a series of high-quality photographs of Phobos orbiting Mars, which NASA experts used to prepare a time-lapse video, the space telescope's website reports.

There are two small moons orbiting Mars today irregular shape- Phobos and Deimos with a diameter of 22 and 12 kilometers, distant from the surface of the red planet by only 10 and 23 thousand kilometers. Today, many scientists believe that both of these moons are not planets, but asteroids captured by the gravity of Mars in the distant past.

Interestingly, Phobos is approaching Mars and will be destroyed and turned into a giant ring of dust in 20-40 million years, while Deimos, on the contrary, is moving away from it and in the distant future it will “escape” from the red planet.

Scientists are now having a hard time explaining why this happens and how Deimos and Phobos could have ended up in their current orbits. Recently, astronomers have suggested that Mars may have had three moons in the past, one of which has already fallen onto its surface.

The Soviet missions Phobos-1 and Phobos-2, as well as the Russian mission Phobos-Grunt, could solve the riddle of the formation of Phobos and Deimos. All of them either did not reach the moons of Mars, or mysteriously failed when approaching Phobos. The reputation of the “cursed moon” was recently strengthened by the American probe MAVEN, which miraculously avoided a collision with Phobos in early March of this year.

Hubble, fortunately for humanity, is located far from Mars, which allows it to monitor its natural satellites “with impunity” and study the mysteries of their birth.

Last May, scientists used it to study individual regions on the surface of Mars, photographing the red planet as it made its closest approach to Earth in years. Along with photographs of Mars, they accidentally received photographs of Phobos emerging from behind the “back” of Mars and beginning its next seven-hour flight around the red planet.

Scientists used these photographs, which Hubble received over 20 minutes, to prepare a video of Phobos flying around Mars. These photographs and videos do not have serious scientific value, but they allow us to see how the moon of a distant planet revolves around its “big sister”.

Events

NASA Mars rover "Curiosity" for the first time filmed the movement of two Martian satellites - Phobos and Deimos, making a series consecutive photographs from the surface of the Red Planet.

For the first time, such a phenomenon as the eclipse of one of the “moons” by another was recorded using photographic telephoto camera lens, and the image turned out to be so clear that even the craters of the satellites can be made out.

In a 30-second period the robot did 41 photos, when the larger of the satellites, Phobos, passed in front of Deimos, completely obscuring it. This phenomenon has been observed August 1. Researchers from Laboratories jet engines NASA combined all the pictures in the right sequence to get the video.

This video will allow scientists to learn more about the satellites of our neighbor Mars, including more detailed information about their orbits. As a result, it will be possible to learn more about the influence of Phobos on the solid surface of the planet. Scientists also plan to figure out exactly how and how systematically the orbit of another satellite, Deimos, changes.

Two of Mars' moons came within view of the rover's camera shortly after it was turned on to transmit data. Thus, observations allowed spend minimal amount rover energy.

Martian scientific laboratory NASA uses a rover "Curiosity" and its 10 scientific instruments to study the history of the Red Planet in the Gale Crater region, where conditions are most favorable for such a project, according to scientists. As is known, "Curiosity" has been on the surface of Mars for a whole year.

Moons of Mars

Mars has only 2 satellites: Phobos(translated from Greek "fear") And Deimos ("horror"). They revolve around the Red Planet, like the Moon around the Earth, so they are turned towards the surface only one side.

Deimos

Externally, these satellites are very look like asteroids, they do not have a round shape like the Moon, but just like our satellite, they are covered with many craters. There is a version that these satellites were once captured by the gravity of Mars when they flew past.

Phobos

The presence of two satellites on Mars was also predicted Johannes Kepler at the beginning of the 17th century, but then the scientist was guided by a strange logic: the further the planet is from the Sun, the more satellites it has.

He also wrote about the satellites of Mars Swift in his famous novel "Gulliver's Travels" in the mid-18th century, describing their sizes and orbits, unaware that the real picture is not much different from fantasy.

The orbit of Phobos is gradually becoming getting closer to the surface of Mars, and the orbit of Deimos is the opposite, moving away from the planet. There is a high probability that one day Phobos will fall on Mars.

The diameter of Phobos is less than 1 percent from diameter earth's satellite– The Moon, and its orbit is much closer to the surface of Mars than the Moon’s orbit to the surface of the Earth.

The diameter of the largest satellite of Mars, Phobos, is 22 kilometers, and its distance from the surface of the planet is only 6 thousand kilometers.

If you look at Phobos from the surface of Mars, its size will be approximately twice smaller the size of the full Moon we see from Earth.

The Earth's satellite, the Moon, cannot be compared with the Martian satellites. The diameter of the Moon is 3476.4 kilometers, when as the average distance between two objects - 384.5 thousand kilometers.

Theories of the origin and nature of the satellites of Mars, the history of their research were accompanied by hoaxes, rumors and legends. Including Phobos and Deimos called alien ships. And scientists have suggested that the number of satellites of the Earth’s twin could have been different.

Prediction of Mars satellites

The idea that Mars has two accompanying bodies was first proposed by the German astrophysicist Johannes Kepler in 1611. He assumed this based on references to observations of a triple planet in the writings of Galileo Galilei. This entry was later interpreted as a description of Saturn with its famous rings.

Despite the incorrect premises, Kepler's assumption turned out to be true. To perpetuate the memory of the astronomer, craters on Mars and the Moon are named after him.

Calculations physical parameters The moons of Mars, even before their discovery, were given by Johnath Swift in 1726 in the book Gulliver's Travels, based only on his imagination. 8 craters on the surface of Phobos are named after the characters in this work.

Asaph Hall discovered the moons of Mars

In the 16th century, all developed observatories in Europe were puzzled by the search for the Moons of a neighboring planet. But Deimos and Phobos were officially discovered on August 11 and 17, 1877, respectively, in the United States by Asaph Hall. We managed to do this during the period of maximum rapprochement between our planet and its neighbor, which occurs every 15 years.

How did the moons of Mars get their name?

Phobos and Deimos received their official names in February 1878 after a long search for successful names. He corresponded with many representatives scientific world, and among the many names proposed, he chose the option of Henry George Madan. He, in turn, took the name from Homer's Iliad. According to another version, these names were suggested by an unknown schoolgirl from Great Britain.

Among the planets of the solar system, asteroids, stars and other cosmic bodies, many names are taken from ancient mythology. The red planet, due to its aggressive surface color, was symbolically named after the ancient Roman god bloody war. Mars, or, as the Greeks called him, Ares. He was considered one of the most revered gods, despite the fact that he symbolized cruelty, strength, and the desire for war for the sake of pleasure. It is logical that the satellites of the planet Mars were named after the children of the god of war of Greek mythology.

According to the beliefs of the Greeks, Ares's children accompanied him and Aphrodite in all battles. Therefore, it is obvious why the satellites today are called Phobos and Deimos, that is, fear and horror.

How many moons does Mars have?

How many moons Mars had remained unknown until 1877. Despite the mathematical calculations of astrologers, suggesting the presence of bodies in the orbit of its neighbor, it was believed that the planet had no natural satellites at all, since they could not be detected. The discovery of these objects became a sensation in the scientific world.

It has now been proven that the planet Mars has two natural satellite, called Phobos and Deimos. The first is located in the inner orbit of the planet at an average distance of 9380 km, the second is two and a half times further.