Planets of the Solar System in order
By MAC definition, there are 8 known planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
All planets are divided into two categories depending on their physical characteristics: terrestrial planets and gas giants.
Schematic representation of the location of the planets
Terrestrial planets
Mercury
The smallest planet in the solar system has a radius of only 2440 km. The period of revolution around the Sun, equated to an earthly year for ease of understanding, is 88 days, while Mercury manages to rotate around its own axis only one and a half times. Thus, his day lasts approximately 59 Earth days. For a long time it was believed that this planet always turned the same side to the Sun, since periods of its visibility from Earth were repeated with a frequency approximately equal to four Mercury days. This misconception was dispelled with the advent of the ability to use radar research and conduct continuous observations using space stations. The orbit of Mercury is one of the most unstable; not only the speed of movement and its distance from the Sun change, but also the position itself. Anyone interested can observe this effect.
Mercury in color, image from the MESSENGER spacecraft
Its proximity to the Sun is the reason why Mercury is subject to the largest temperature changes among the planets in our system. The average daytime temperature is about 350 degrees Celsius, and the nighttime temperature is -170 °C. Sodium, oxygen, helium, potassium, hydrogen and argon were detected in the atmosphere. There is a theory that it was previously a satellite of Venus, but so far this remains unproven. It does not have its own satellites.
Venus
The second planet from the Sun, the atmosphere is almost entirely composed of carbon dioxide. It is often called the Morning Star and the Evening Star, because it is the first of the stars to become visible after sunset, just as before dawn it continues to be visible even when all the other stars have disappeared from view. The percentage of carbon dioxide in the atmosphere is 96%, there is relatively little nitrogen in it - almost 4%, and water vapor and oxygen are present in very small quantities.
Venus in the UV spectrum
Such an atmosphere creates a greenhouse effect; the temperature on the surface is even higher than that of Mercury and reaches 475 °C. Considered the slowest, a Venusian day lasts 243 Earth days, which is almost equal to a year on Venus - 225 Earth days. Many call it Earth's sister because of its mass and radius, the values of which are very close to those of Earth. The radius of Venus is 6052 km (0.85% of Earth's). Like Mercury, there are no satellites.
Earth
The third planet from the Sun and the only one in our system where there is liquid water on the surface, without which life on the planet could not have developed. At least life as we know it. The radius of the Earth is 6371 km and, unlike other celestial bodies in our system, more than 70% of its surface is covered with water. The rest of the space is occupied by continents. Another feature of the Earth is the tectonic plates hidden under the planet's mantle. At the same time, they are able to move, albeit at a very low speed, which over time causes changes in the landscape. The speed of the planet moving along it is 29-30 km/sec.
Our planet from space
One revolution around its axis takes almost 24 hours, and a complete passage through the orbit lasts 365 days, which is much longer in comparison with its closest neighboring planets. The Earth's day and year are also accepted as a standard, but this is done only for the convenience of perceiving time periods on other planets. The Earth has one natural satellite - the Moon.
Mars
Mars as seen by the Hubble Space Telescope in 2003
The fourth planet from the Sun, known for its thin atmosphere. Since 1960, Mars has been actively explored by scientists from several countries, including the USSR and the USA. Not all exploration programs have been successful, but water found at some sites suggests that primitive life exists on Mars, or existed in the past.
The brightness of this planet allows it to be seen from Earth without any instruments. Moreover, once every 15-17 years, during the Confrontation, it becomes the brightest object in the sky, eclipsing even Jupiter and Venus.
The radius is almost half that of Earth and is 3390 km, but the year is much longer - 687 days. He has 2 satellites - Phobos and Deimos .
How easy is it to remember the order of the planets?
Children remember various rhymes and poems well. As in the example of remembering the colors of the rainbow, there are rhymes for remembering the planets. Below are options for rhymes for memorizing the planets. Read them to your children so that they can remember and better understand the names of the planets of the solar system.
Reading book about planets: for children to quickly memorize
Variant of a rhyme for children about the planets
Mercury
Sun-scorched Mercury is only slightly larger than Earth's satellite the Moon. Like the Moon, Mercury is practically devoid of an atmosphere and cannot smooth out the traces of impact from falling meteorites, so it, like the Moon, is covered with craters. The day side of Mercury gets very hot from the Sun, while on the night side the temperature drops hundreds of degrees below zero. There is ice in the craters of Mercury, which are located at the poles. Mercury completes one revolution around the Sun every 88 days.
Iron Mars
The fourth planet from the Sun is called Mars. It is unusual in that its entire surface is covered with iron. Because of this, the planet has a reddish-orange hue. Although Mars is smaller than Earth, a day on it lasts almost like ours - 24 hours 37 minutes. But the Martian year is much longer than the Earth's. In search of an answer to the question “Is there life on Mars?”, scientists have created special vehicles - rovers that walk on the surface of Mars and study the red planet. However, so far they have not been able to find signs of life on Mars.
Mars
Although details of the surface of Mars are difficult to see from Earth, observations through a telescope indicate that Mars has seasons and white spots at the poles. For decades, people believed that the bright and dark areas on Mars were patches of vegetation, that Mars might be a suitable place for life, and that water existed in the polar ice caps. When the Mariner 4 spacecraft arrived at Mars in 1965, many scientists were shocked to see photographs of the murky, cratered planet. Mars turned out to be a dead planet. More recent missions, however, have revealed that Mars holds many mysteries that remain to be solved.
Our home is planet Earth
If the Sun is a ball of gas, then maybe we also live on a star? Of course not. Under our feet there is a hard surface on which we can walk, run, rollerblade and ride a car. This cannot be done on the Sun, because it consists of gas. What then should we call the place where we live? Welcome to planet Earth! A planet is a space object that looks like a huge ball. There are several other planets near the Earth, and they are all very different: large and small, cold and hot, fast and slow. Let's get to know them!
Planets are giants
There are four gas giants located beyond the orbit of Mars: Jupiter, Saturn, Uranus, Neptune. They are located in the outer solar system. They are distinguished by their massiveness and gas composition.
Planets of the solar system, not to scale
Jupiter
The fifth planet from the Sun and the largest planet in our system. Its radius is 69912 km, it is 19 times larger than the Earth and only 10 times smaller than the Sun. The year on Jupiter is not the longest in the solar system, lasting 4333 Earth days (less than 12 years). His own day has a duration of about 10 Earth hours. The exact composition of the planet's surface has not yet been determined, but it is known that krypton, argon and xenon are present on Jupiter in much larger quantities than on the Sun.
Jupiter, image from Voyager 1 probe
There is an opinion that one of the four gas giants is actually a failed star. This theory is also supported by the largest number of satellites, of which Jupiter has many - as many as 67. To imagine their behavior in the planet’s orbit, you need a fairly accurate and clear model of the solar system. The largest of them are Callisto, Ganymede, Io and Europa. Moreover, Ganymede is the largest satellite of the planets in the entire solar system, its radius is 2634 km, which is 8% greater than the size of Mercury, the smallest planet in our system. Io has the distinction of being one of only three moons with an atmosphere.
Saturn
The second largest planet and the sixth in the solar system. In comparison with other planets, it is most similar to the Sun in the composition of chemical elements. The radius of the surface is 57,350 km, the year is 10,759 days (almost 30 Earth years). A day here lasts a little longer than on Jupiter - 10.5 Earth hours. In terms of the number of satellites, it is not much behind its neighbor - 62 versus 67. The largest satellite of Saturn is Titan, just like Io, which is distinguished by the presence of an atmosphere. Slightly smaller in size, but no less famous are Enceladus, Rhea, Dione, Tethys, Iapetus and Mimas. It is these satellites that are the objects for the most frequent observation, and therefore we can say that they are the most studied in comparison with the others.
Saturn, photographed by the Cassini spacecraft in 2007
For a long time, the rings on Saturn were considered a unique phenomenon unique to it. Only recently it was established that all gas giants have rings, but in others they are not so clearly visible. Their origin has not yet been established, although there are several hypotheses about how they appeared. In addition, it was recently discovered that Rhea, one of the satellites of the sixth planet, also has some kind of rings.
Uranus
The seventh and third largest planet, with a radius of 25,267 km. It is rightly considered the coldest planet among the rest, the temperature reaches -224 degrees Celsius. The length of a year is 30,685 days in earthly terms (almost 84 years), but a day is not much less than an earthly day - just over 17 hours. Due to the strong inclination of the planet's axis, sometimes it seems as if it does not rotate like the rest of the celestial bodies of our system, but rolls like a ball. This can be observed by anyone interested in astronomy; a geometric model of the solar system will clearly demonstrate this effect.
Uranus as seen by Voyager 2 in 1986
It has much fewer satellites than neighboring Saturn, only 27. The most famous are Titania, Ariel, Oberon, Umbriel and Miranda. They are not as large as satellites.
It is noteworthy that while observing Uranus through his telescope, astronomer William Herschel at first did not realize that he was observing the planet, being sure that he was seeing a comet.
Neptune
The size of the eighth planet in the solar system is very close to its nearest neighbor, Uranus. The radius of Neptune is 24547 km. A year on the planet is 60,190 days (approximately 164 Earth years). The strongest winds in our system have been recorded in the atmosphere, with speeds reaching 260 m/s.
Neptune as seen from Voyager 2
Compared to the other giant planets, it has very few satellites - only 14. The most famous of them are Triton, the third satellite in the solar system that has an atmosphere, Proteus and Nereid.
It is noteworthy that this is the only planet that was discovered not through observations, but through mathematical calculations.
Solar System Research - 2021/2022
Since the late 1950s, automatic interplanetary stations have been the main source of information about the bodies of the Solar System. Overflights have been carried out, artificial satellites have entered orbit, matter has been delivered to Earth, and self-propelled vehicles operate on the surface of some bodies. We will tell you about the events of the outgoing year 2022 and what is planned in this regard for 2022 in our review. We will talk about the Sun, major planets, their satellites, asteroids and outer space beyond the orbit of Neptune.
Sun
Currently, several solar probes are studying our luminary in interplanetary space: the SOHO station (a joint project of NASA and ESA) and the American probes WIND, ACE and DSCOVR are located at the Lagrange point L₁ of the Sun-Earth system. Also, extensive programs for studying the Sun and circumsolar space are carried out by probes launched in recent years - the American Parker and the European Solar Orbiter. Parker, thanks to flybys of Venus, consistently tightens its heliocentric orbit. In November, the device flew at a distance of less than 15 solar radii from our star - a record for spacecraft. Even closer approaches to the Sun are planned in the future.
Parker solar probe. parkersolarprobe.jhuapl.edu
Moon
The Chinese station "Chang'e-5" (the main block of the lunar apparatus that previously delivered a sample of lunar material to Earth) first reached the L₁ point of the Sun-Earth system in March, then in September it again began moving towards the Moon. Also during 2022, the Yutu-2 lunar rover continued to explore the surface of the far side of the Moon. The Queqiao apparatus continues to operate at the Lagrange point L₂ of the Earth-Moon system. Its task is to relay signals from Yutu-2 and the landing platform.
Early next year, the unmanned Orion spacecraft will launch to the Moon on a super-powerful Space Launch System rocket as part of the Artemis program. The Orion spacecraft will spend about three weeks in space, including three days in retrograde orbit of the Moon. The follow-up mission, Artemis 2, is planned to carry out the first manned flight of Orion. As an additional payload, more than 10 cubesats will be launched to the Moon - small spacecraft for exploring the Moon and cislunar space. Also in 2022, it is possible to launch the Indian landing vehicle Chandrayaan-3, carrying a lunar rover on board.
Orion spacecraft. flickr.com/nasaorion
In addition, in 2022 it is possible to launch several more spacecraft to the Moon, including from the UAE and South Korea.
As for our domestic launches, it was previously announced that Luna-25 would be launched in 2022, but the prospects for this long-planned launch remain rather vague.
Mercury
In October 2022, the European Space Agency's BepiColombo probe set off for the planet closest to the Sun. This year, during a long flight to Mercury in August, he conducted a flyby study of Venus and in October for the first time flew past his final goal - Mercury. On June 23, 2022, the second flyby of Mercury is due to take place, and before the artificial satellite enters orbit in December 2025, six more flybys of this planet will be made in 2023–2025.
There are no other launches to Mercury currently planned.
Venus
Since December 2015, the Japanese artificial satellite Akatsuki has been orbiting this planet. Interestingly, this probe, launched in May 2010, was originally scheduled to enter orbit in December 2010, but that operation ended unsuccessfully; The station's flight continued around the Sun, but as a result, the task was completed with a delay of five years. Apparently, if no serious problems occur, this device will work until it burns up in the atmosphere of Venus and will share the fate of its predecessors.
Significantly less known solar devices in the context of Venus research are the American Parker and the European Solar Orbiter. They also make flybys of Venus. Parker flew by Venus for the fourth and fifth time in February and October of this year, and the next flyby will not take place until 2023. Another probe flew near Venus for the second time in August 2022, with an interval of one day from BepiColombo, and on November 21, it flew past the Earth. On September 3, 2022, Solar Orbiter will fly by Venus for the third time. It is clear that the main target of these devices remains the Sun and the scope of research on Venus is quite limited, nevertheless they are also of scientific importance.
Earth
The inclusion of our planet in such a review seems paradoxical, but the fact is that many interplanetary vehicles fly by our planet during their flight to other celestial bodies. Of course, the value of the scientific results obtained during these flights is quite limited: in the course of these studies, information about the magnetic field is obtained, and calibration sessions of the activity of scientific instruments and television receivers are carried out. As already noted, this year in November the American Solar Orbiter probe flew past the Earth, and on October 16, 2022, “Lucy”: it is heading towards the Trojan asteroids of Jupiter and should fly past our planet for the first time at an altitude of 300 km. There has been an amateur observation program for similar flights for several years.
Spacecraft "Lucy". Photo by NASA
Mars
Currently, there are nine devices in the orbits of this planet in working order - these are the American Mars Odyssey, Mars Reconnaissance Orbiter, MAVEN, the European Mars Express, the Indian Mangalyaan, the Russian-European Trace Gas Orbiter, the Al-Amal apparatus. (UAE) and the Chinese Tianwen-1. Three American probes (the InSight probe, the Curiosity and Perseverance rovers) and the Chinese Zhuzhong rover are operating on the surface.
Perseverance landed on the Red Planet in February, Zhuzhong in April. In the summer, for the first time in the history of astronautics, a helicopter was launched several times from Perseverance.
In the fall of 2022, the European rover Rosalyn Franklin and the Russian landing platform Kazachok will launch to Mars under the Russian-European ExoMars program. The landing of these devices is expected in June 2023. After landing and departure of the rover, the stationary landing platform will continue to operate as an automatic research station.
Jupiter
This year the flight of the American artificial satellite of Jupiter “Juno” continued. This automatic station has been conducting research on Jupiter and its largest moons since 2016.
The launch of the European Space Agency's Jupiter Icy Moon Explorer (JUICE) heavy station into the Jupiter system has been postponed to 2023, while the flight period will increase to 9 years. Accordingly, the probe's arrival in the Jupiter system is postponed until 2032.
Saturn
There are currently no vehicles in orbit around this planet, and no launches to it are planned in 2022.
Small bodies of the Solar System
In 2022, the main unit of the Japanese Hayabusa-2 station continues to fly. Earlier, during a close flyby of the Earth, a return vehicle separated from it, delivering the material of one of the asteroids to Earth for the second time. After this, an additional flight program was adopted, providing for the flyby of one of the small asteroids in the summer of 2026 and entry into orbit around the other in the summer of 2031.
The American station OSIRIS-REx conducted its last studies in the spring of 2022 of the small asteroid Benu, around which it had been orbiting since the end of 2022. With samples of matter taken from its surface in May last year, it began moving towards Earth. Arrival is expected in September 2023.
In the past year, two new devices have been launched towards asteroids. On October 16, the Lucy probe took off. The flight program first provides for two successive flybys of the Earth: on October 16, 2022, “Lucy” should fly by our planet for the first time at an altitude of 300 km, the next flyby will take place in December 2024. In April 2025, during the passage of the main asteroid belt, a flyby of the asteroid Donald Johanson is planned, and then in 2027, the station should arrive at the Lagrange point of the Sun-Jupiter system and conduct a study of four “Greek” asteroids there. In December 2030, the station should fly past the Earth for the third time, and in March 2033 it will arrive at the L5 Lagrange point of the Sun-Jupiter system: there it should conduct a study of the double system of “Trojan” asteroids Patroclus and Menoetius.
On November 24, 2022, the American DART station was launched using Falcon 9. At the end of September 2022, the device will crash into Dimorph, a satellite of the near-Earth asteroid Didim. The goal of the mission is to try to change the orbital parameters of this binary system and thereby develop a methodology for preventive operations to change the trajectory of dangerous near-Earth asteroids.
In August 2022, the American station of the same name will launch to the iron asteroid Psyche. After a flyby and gravity maneuver near Mars in May 2023, the station will enter orbit around the asteroid in early 2026. Together with Psyche, the small Janus apparatus will be launched towards the double system of main belt asteroids.
For the Artemis 1 lunar mission in January 2022, two small NEA Scout CubeSats could be launched as an additional payload to two small asteroids, with the mission objective subject to change depending on the launch date or other factors.
Outer Solar System
Far beyond the orbit of Neptune, the American space probes Voyager 1, Voyager 2 and New Horizons continue to fly. Launched in 1977, Voyagers continue to transmit valuable information about the interplanetary medium at an enormous distance from the Sun - more than 155 AU. e. Currently, work with stations is carried out on the basis of strict savings in fuel and other resources. The New Horizons probe, which previously explored Pluto and objects from the Kuiper Belt, can operate until approximately 2035, as long as there are enough fuel reserves for orientation and the sources of the radioisotope thermoelectric generator do not dry up.
Lev Kamentsev
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See also:
- Year in the Solar System (02/26/2013)
- Cosmos-2070 (04/07/2020)
- Stars - planets - life - civilization (05.10.2014)
- The closest habitable exoplanets: where they are, how they can be observed and how to reach them (06/28/2016)
- Juno and maybe (12.07.2016)
- Exomoons (07/03/2018)
- Catch a comet (05/20/2014)
- First to first from the Sun (10/20/2015)
- First Neptune Trojan in L5 (08/17/2010)
