Education, The science
What is Mars, the characteristic of the planet. Distance to Mars
Mars is the fourth planet of our solar system and the second is the smallest after Mercury. Named after the ancient Roman god of war. Her nickname "Red Planet" comes from the reddish shade of the surface, which is due to the predominance of iron oxide. Every few years, when Mars is in opposition to the Earth, it is most noticeable in the night sky. For this reason, people have been observing the planet for thousands of years, and its appearance in the sky played a big role in the mythology and astrological systems of many cultures. In the modern era, it has become a real treasure trove of scientific discoveries that have expanded our understanding of the solar system and its history.
The size, orbit and mass of Mars
The radius of the fourth planet from the Sun is about 3396 km at the equator and 3376 km in the polar regions, which corresponds to 53% of the Earth's radius. And although it is about half the size, the mass of Mars is 6.4185 x 10²³ kg, or 15.1% of the mass of our planet. The slope of the axis is similar to the terrestrial one and is equal to 25.19 ° to the plane of the orbit. This means that the fourth planet from the Sun is also experiencing a change in the seasons of the year.
At its maximum distance from the Sun Mars moves in orbit at a distance of 1.666 a. E., Or 249.2 million km. At perihelion, when it is closest to our luminary, it is removed from it by 1.3814 a. E., Or 206.7 million km. The red planet requires 686,971 Earth days, equivalent to 1.88 Earth years to make a revolution around the Sun. In the Martian days, which are equal to one day and 40 minutes on Earth, the year lasts 668,5991 days.
Soil Composition
With an average density of 3.93 g / cm³, this characteristic of Mars makes it less dense than the Earth. Its volume is about 15% of the volume of our planet, and the mass is 11%. Red Mars is a consequence of the presence on the surface of iron oxide, better known as rust. The presence of other minerals in the dust provides the presence of other shades - gold, brown, green, etc.
This planet of the terrestrial group is rich in minerals containing silicon and oxygen, metals and other substances, which usually form part of stony planets. The soil is slightly alkaline and contains magnesium, sodium, potassium and chlorine. Experiments carried out on soil samples also show that its pH is 7.7.
Although liquid water can not exist on the surface of Mars because of its fine atmosphere, large concentrations of ice are concentrated within the polar caps. In addition, the belt of permafrost extends from the pole to 60 ° latitude. This means that water exists under most of the surface as a mixture of its solid and liquid state. Radar data and soil samples confirmed the presence of underground reservoirs also in the middle latitudes.
Internal structure
The planet Mars, whose age is 4.5 billion years, consists of a dense metal core surrounded by a silicon mantle. The core consists of iron sulphide and contains twice as many light elements as the core of the Earth. The average thickness of the crust is about 50 km, the maximum is 125 km. If we take into account the size of the planets, the earth's crust, whose average thickness is 40 km, is 3 times thinner than the Martian crust.
Modern models of its internal structure assume that the size of the nucleus in the radius is 1700-1850 km, and it consists mainly of iron and nickel with approximately 16-17% sulfur. Because of its smaller size and weight, the gravity on the surface of Mars is only 37.6% of the earth's surface. Acceleration of free fall here is 3,711 m / s², compared with 9,8 m / s² on our planet.
Surface characteristics
Red Mars from above is dusty and dry, and geologically it is very reminiscent of the Earth. It has plains and ridges, and even the largest sand dunes in the solar system. There is also the highest mountain - the shield volcano Olympus, and the longest and deepest canyon - the Mariner Valley.
Shock craters are typical elements of the landscape, with which the planet Mars is speckled. Their age is estimated in billions of years. Because of the slow rate of erosion, they are well preserved. The largest of them is the valley of Hellas. The crater's circumference is about 2300 km, and its depth reaches 9 km.
On the surface of Mars can also distinguish ravines and canals, and many scientists believe that they once flowed through the water. Comparing them with similar formations on Earth, it can be assumed that they are at least partially formed by water erosion. These channels are quite large - 100 km wide and 2 thousand km long.
Satellites of Mars
Mars has two small moons, Phobos and Deimos. They were discovered in 1877 by astronomer Asaf Hall and bear the names of mythical characters. In accordance with the tradition of obtaining names from classical mythology, Phobos and Deimos are the sons of Ares - the Greek god of war, who was the prototype of Roman Mars. The first of them embodies fear, and the second is confusion and horror.
Phobos is about 22 km in diameter, and the distance to Mars from it is 9234.42 km at perigee and 9517.58 km at apogee. This is below the synchronous altitude, and the satellite takes only 7 hours to fly around the planet. Scientists have calculated that in 10-50 million years Phobos can fall to the surface of Mars or disintegrate into a ring structure around it.
Deimos has a diameter of about 12 km, and its distance to Mars is 23,455.5 km at perigee and 23,470.9 km at apogee. The satellite spends a full revolution in 1.26 days. Mars may have additional satellites, whose dimensions are less than 50-100 m in diameter, and there is a dust ring between Phobos and Deimos.
According to scientists, these satellites were once asteroids, but then they were captured by the planet's gravity. The low albedo and composition of both moons (carbon-containing chondrite), which is similar to the material of asteroids, support this theory, and the unstable orbit of Phobos seems to suggest a recent seizure. Nevertheless, the orbits of both moons are circular and are in the plane of the equator, which is unusual for trapped bodies.
Atmosphere and climate
The weather on Mars is due to the presence of a very thin atmosphere, which consists of 96% carbon dioxide, 1.93% - argon and 1.89% - nitrogen, and traces of oxygen and water. It is very dusty and contains solid particles measuring 1.5 μm in diameter, which stains the Martian sky, when viewed from the surface, in a dark yellow color. Atmospheric pressure varies within the range of 0.4-0.87 kPa. This is equivalent to about 1% of the earthly level at sea level.
Due to the thin layer of the gas shell and the greater distance from the Sun, the surface of Mars is warming up much worse than the surface of the Earth. On average, it is -46 ° C. In winter, it falls to -143 ° C at the poles, and in the summer at noon the equator reaches 35 ° C.
On the planet, dust storms are raging, which turn into small tornadoes. More powerful hurricanes arise when dust rises and heats up by the Sun. Winds increase, creating storms, the scale of which is measured in thousands of kilometers, and their duration - several months. They actually hide almost the entire surface area of Mars from the field of view.
Traces of methane and ammonia
In the atmosphere of the planet, traces of methane, whose concentration is 30 parts per billion, were also found. It is estimated that Mars should produce 270 tons of methane per year. After entering the atmosphere, this gas can exist only for a limited period of time (0.6-4 years). His presence, despite a short life time, indicates that there must be an active source.
Among the proposed options - volcanic activity, comets and the presence of methanogenic microbial life forms beneath the surface of the planet. Methane can be obtained from non-biological processes called serpentinization, involving water, carbon dioxide and olivine, which is often found on Mars.
The satellite Mars Express also found ammonia, but with a relatively short lifetime. It is not clear what produces it, but volcanic activity was suggested as a possible source.
Exploring the planet
Attempts to find out what Mars is, began in the 1960s. In the period from 1960 to 1969, the Soviet Union launched 9 unmanned spacecraft to the Red Planet, but all of them failed to achieve their goal. In 1964, NASA began to launch Mariner probes. The first became "Mariner-3" and "Mariner-4". The first mission failed during the deployment, but the second mission, launched 3 weeks later, successfully completed a 7.5-month journey.
Mariner 4 took the first near pictures of Mars (showing impact craters) and provided accurate data on atmospheric pressure at the surface and noted the absence of a magnetic field and radiation belt. NASA continued the program by launching another pair of Mariner 6 and 7 flyby probes that reached the planet in 1969.
In the 1970s, the USSR and the United States competed in the one who would first put an artificial satellite into orbit of Mars. The Soviet M-71 program included three spacecraft - Kosmos-419 (Mars-1971C), Mars-2 and Mars-3. The first heavy probe crashed during launch. Subsequent missions, Mars-2 and Mars-3, were a combination of an orbiter and a landing module and became the first stations to make an extraterrestrial landing (except the Moon).
They were successfully launched in mid-May 1971 and flew from Earth to Mars for seven months. On November 27 the descent vehicle "Mars-2" made an emergency landing due to the failure of the onboard computer and became the first man-made object that reached the surface of the Red Planet. December 2, "Mars-3" made a regular landing, but its transfer was interrupted after 14.5 from the broadcast.
In the meantime, NASA continued the Mariner program, and in 1971 the 8 and 9 probes were launched. The Mariner 8 during launch and fell into the Atlantic Ocean. But the second spacecraft not only reached Mars, but also became the first successfully put into its orbit. While the dust storm of planetary scale lasted, the satellite managed to make several photos of Phobos. When the storm ceased, the probe took pictures, which gave more detailed evidence that water had once flowed on the surface of Mars. It was established that the hill called Snow of Olympus (one of the few objects that remained visible during the planetary dust storm) is also the highest education in the Solar System, which led to its renaming to Mount Olympus.
In 1973, the Soviet Union sent four more probes: the Mars 4th and 5th orbits, as well as the Mars-6 orbiter and descent probes and 7. All interplanetary stations, except for Mars-7, transmitted data , And the expedition "Mars-5" was the most successful. Before the depressurization of the transmitter body, the station managed to transmit 60 images.
By 1975, NASA launched Viking 1 and 2, which consisted of two orbiting vehicles and two descent vehicles. The mission to Mars was to search for traces of life and to monitor its meteorological, seismic and magnetic characteristics. The results of biological experiments aboard the descending "Vikings" were inconclusive, but a reanalysis of the data published in 2012 suggested the presence of signs of microbial life on the planet.
Orbital apparatuses provided additional data confirming that once on Mars there was water - large floods formed deep canyons, thousands of kilometers long. In addition, sections of branched flows in the southern hemisphere suggest that precipitation has once occurred here.
Resumption of flights
The fourth planet from the sun was not explored until the 1990s when NASA sent a mission to Mars Pathfinder, consisting of a spacecraft that landed a station with a moving probe called "Sojourner". The device landed on Mars on July 4, 1987 and became evidence of the consistency of technologies that will be used in further expeditions, such as landing with air cushions and an automatic obstacle clearance system.
The next mission to Mars is the mapping satellite of MGS, it reached the planet on September 12, 1997 and began work in March 1999. During one full Martian year from a low altitude almost in polar orbit, he studied the entire surface and atmosphere and sent more data about the planet , Than all the previous missions combined.
On November 5, 2006, MGS lost contact with Earth, and NASA's efforts to restore it were discontinued on January 28, 2007.
In 2001, to find out what Mars is, Mars Odyssey Orbiter was sent. His goal was to find evidence of the existence of water and volcanic activity on the planet using spectrometers and thermal imagers. In 2002, it was announced that the probe detected a large amount of hydrogen - evidence of the existence of huge ice deposits in the upper three meters of the soil within 60 ° from the south pole.
On 2 June 2003, the European Space Agency (ESA) launched Mars Express, a spacecraft consisting of a Beagle-2 satellite and a descending probe. It entered orbit on December 25, 2003, and the probe entered the atmosphere of the planet on the same day. Before ESA lost contact with the descent vehicle, Mars Express Orbiter confirmed the presence of ice and carbon dioxide at the south pole.
In 2003, NASA began exploring the planet under the MER program. It used two mars rover "Spirit" and "Oportyunity." The mission to Mars was to investigate various rocks and soils in order to find evidence of the presence of water here.
On 12.08.05 Mars Reconnaissance Orbiter (MRO) was launched, which reached the orbit of the planet on 10.03.06. On board the device are scientific instruments designed to detect water, ice and minerals on the surface and under it. In addition, MRO will provide support for future generations of space probes: the weather on Mars is monitored daily and its surface condition, search for future landing sites and testing of a new telecommunications system that will speed up communication with the Earth.
On August 6, 2012, the NASA MSL Martian Science Laboratory and the "Curiosity" rover landed in the Gale crater. With their help, many discoveries were made concerning local atmospheric and surface conditions, and organic particles were also discovered.
On November 18, 2013, in another attempt to find out what Mars is, the MAVEN satellite was launched, the purpose of which is to study the atmosphere and retransmit signals from robotic rovers.
Research continues
The fourth planet from the Sun is the most studied in the Solar system after the Earth. At present, Opportunity and Curiosity stations are operating on its surface, and five spacecraft - Mars Odyssey, Mars Express, MRO, MOM and Maven - operate in orbit.
These probes managed to convey incredibly detailed images of the Red Planet. They helped to discover that once there was water, and confirmed that Mars and Earth are very similar - they have polar caps, a change of seasons, an atmosphere and the presence of water. They also showed that organic life can exist today and, most likely, was earlier.
The obsession with humanity to find out what Mars is is not weakening, and our efforts to study its surface and unravel its history are far from complete. In the coming decades, we will probably continue to send rovers there and for the first time send a person there. And over time, given the availability of the necessary resources, the fourth planet from the Sun will someday become habitable.
Similar articles
Trending Now