Planetary atmosphere is wrapped around planetary bodiesNeutral gasandIonized gasThe general name of.The reason why the atmosphere around the planet body does not escape is that it is bound by the gravity and magnetic field of the planet.The study of planetary atmosphere also includes the study of satellite atmosphere of planets.
The planets in the solar system have different atmospheric states due to their different sizes and distances from the sun.
Chinese name
Planetary atmosphere
Foreign name
planetary atmosphere
Discovery time
1961
Introduction
The general term of neutral gases wrapped in planetary bodies
exceptearthOutside,solar systemThe other planets in China all have their own unique atmosphere. Studying their structure, physical state, chemical composition and general state of operation will help to explore the evolution of the Earth's atmosphere.
Before the 1940s, it was only usedAstronomical telescopeandradarWait on the earth to observe other planets.Since 1961, we have begun to use planetary probes to detect other planets and obtain data. Some of these probes send back photos from more than 1000 kilometers to more than 1 million kilometers away from the planet, and some landers send back photos and data to the Earth after soft landing on the planet.With the continuous development of exploration means, the research of planetary atmosphere has made great progress.The solar system hasplanets, in the order from near to far from the sun, they are:Mercury、Venus, EarthMars、Jupiter、Saturn、Uranus、Neptune。Between Mars and Jupiter, there are manyasteroid。UsuallyMercuryVenus, Earth and Mars are called inner planets, while Jupiter, Saturn, Uranus, Neptune andPluto, calledouter planet。Mercury is only about four tenths of the distance from the sun to the earth, and the solar radiation energy obtained is large. The temperature of Mercury's surface at noon can reach 700K, and the temperature at midnight is about 100K.Mercury has a small gravitational mass and escape speed, so gas molecules are easy to escape from the gravitational field of Mercury.Therefore, the atmosphere of Mercury is extremely thin, and its pressure is less than 2 × 10-9 hPa.This article mainly introduces the atmospheric state of Venus, Mars, Jupiter and Saturn.Planetary atmosphere is wrapped around planetary bodiesNeutral gasAnd ionized gas.[1]
Detailed introduction
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Venusian atmosphere
The main components arecarbon dioxide, accounting for about 95%, nitrogen accounting for about 3.5%, and a small amount of argoncarbon monoxide、steam、Hydrogen chlorideandHydrogen fluorideEtc.The atmosphere of Venus is thicker than that of the Earth. The pressure on the surface of Venus is about 90 times that of the Earth, that is, about 90000 hPa.The air pressure at 30km altitude is about 10000 hPa, that at 50km altitude is about 1000 hPa, and that at 80km altitude is about 10 hPa.The atmosphere of Venus can be divided into several characteristic layers from bottom to top: ① The atmosphere between 0 and 31 kilometers is clean, and the atmosphere is almost free of impurities, but the lightning and thunder keep on. ②31~68km is the cloud layer, which is yellow due to sulfide.According to the distribution of cloud particle size, it can be divided into four layers: 31~48km is thin haze layer, 48~52km is low cloud layer, 52~58km is medium cloud layer, and 58~68km is high cloud layer.There are sulfuric acid droplets, sulfur of different concentrations and high content of aerosols in the whole cloud system.High clouds are uneven.The density of middle cloud layer increases downward, with a maximum at 52km and a distinct bottom at about 50km.The low cloud layer changes most with area and time.The probe landing at the north pole of Venus found by infrared observation that there was a polar hole in the atmosphere of the polar region, which was about 1100 kilometers wide. The airflow was sinking and the clouds were thin.The carbon dioxide in the atmosphere of Venus causes very significantgreenhouse effectThe surface temperature of Venus is as high as 750K, and basically does not change with the region, season, day and night.Venus probeIt is measured that the temperature in the Arctic is about 10K higher than that in the equator.The temperature between 0 km and 60 km drops sharply with altitude, and the temperature at 60 km altitude is about 300K.Above 60km, the temperature drops slowly, and above 68km, it is close to the same temperature, about 200K.
Venus is one of the major planets (the other is Uranus) in the solar system that rotate in the opposite direction, so the sun rises in the west and sets in the east when viewed from Venus.Its volume and mass are slightly smaller than that of the earth.Venus rotates in 243 days (Earth time).The whole planet is almost covered by deep clouds all year round.Ultraviolet observations show that the cloud layer of Venus has bright and dark areas, often in a large inverted Y-shaped shape. The handle of the Y-shaped shape is about parallel to the equator. The Y-shaped cloud moves very fast, and it can circle Venus in about 5 days. From this, it can be inferred that the wind speed in the upper air can be as high as 200 meters/second.However, the wind speed decreases rapidly downward, which is 50 m/s at 45 km from the surface and only about 2 m/s at 10 km from the surface.The above Y-shaped clouds sometimes disappear for several weeks and then reappear.It is believed that this is caused by large-scale convection caused by solar heating.
Venus has a dense atmosphere. The surface pressure is about 92 times that of the earth. Venus has a strong greenhouse effect. Its main component is carbon dioxide, accounting for about 95%.
Martian atmosphere
The main components are carbon dioxide (95%), nitrogen (2-3%), argon (1-2%), carbon monoxide (0.1%) and oxygen (0.1%)ozoneAnd hydrogen, water vapor only accounts for 0.01% on average.Martian atmosphereThe content of carbon dioxide decreases with height;At the height of 100km, the content of oxygen accounts for 50%, and at the height of 140km, the measured content of oxygen is 6 times larger than that of carbon dioxide.The density of the Martian atmosphere is less than 1% of the Earth's atmosphere. The average atmospheric pressure on the Martian surface is only 7.5 hPa, which is equivalent to the atmospheric pressure 30~40 kilometers above the Earth.
Mars is much smaller than the Earth. Its volume is only 0.15 of the Earth's, and its mass is only 1/9 of the Earth's. Mars also has four seasons. Since it orbits the sun for about 687 days (Earth time), the length of each season is about twice as long as that of the Earth.
The average temperature on the surface of Mars is 240K, the maximum temperature in the equatorial region exceeds 300K in the daytime, and it is below 200K at night, with great diurnal variation;The temperature in the polar region is as low as 150K in winter.From the surface up, the temperature drops. Above the height of 40km, the average temperature is 140K, but there are significant irregular changes.Clouds also exist in the Martian atmosphere.There are clouds composed of water ice at the height of 15~30km, and white clouds composed of carbon dioxide (dry ice) at the height of about 45km.In spring and summer in the Northern Hemisphere, there are also water ice clouds on the windward side of the huge volcano.The wind speed on the surface of Mars is generally small, but sometimes strong winds also occur. The movement of clouds in the low latitude in summer shows that the upper air wind of 15~30km is easterly, and the wind speed is about 30~55m/s;The westerly wind blows in mid latitude in winter.The airflow in the equatorial region is still uncertain.The most spectacular meteorological phenomenon on Mars is dust storm, which can often develop to the planetary scale and sometimes almost cover the entire planet surface.During the two major dust storms in 1971 and 1973, the vast area was covered for several weeks, making the atmosphere below the height of 11 km opaque, and the maximum wind speed was 140 m/s.Such planetary scale dust storms often occur when Mars is near the perihelion.The origin of dust storms is often at the latitude of direct solar radiation in the southern hemisphere, covering the entire southern hemisphere within a few weeks.Particularly large dust storms can also spread to the northern hemisphere, thereby covering the entire planet.
In the South Pole and North Pole of Mars, there are whitePolar crownThe range of the polar cap varies with seasons.In winter, it is composed of water ice and dry ice (solid carbon dioxide), with the largest range;The scope gradually narrows after the arrival of spring;In summer, the range of the polar cap is the smallest, but it does not disappear. It is a permanent polar cap completely composed of water ice;With the advent of autumn, the temperature of the polar region gradually drops below the freezing point (150K) of carbon dioxide, and carbon dioxide begins to condense, expanding the polar range.It can be seen that the increase or decrease of the polar cap range is caused by the sublimation of carbon dioxide and dry ice caused by temperature changes.
The Martian atmosphere is thinner than the Earth's atmosphere. The surface atmospheric pressure is equivalent to the pressure of the Earth's atmosphere at a height of 35 kilometers. It has strong local and global dust. The main component is carbon dioxide, accounting for about 95%.
Jupiter's atmosphere
The main components are hydrogen (88.6%), helium (11.2%) and a small amount of ammonia, methane, water vapor, oxygen, nitrogen and sulfide, with a thickness of about 1000 km.
Jupiter isNine planets in the solar systemThe largest one in the world. Its volume is about 1316 times that of the earth, and its mass is about 319 times that of the earth. From the center to 71370 kilometers, it is successively composed of solid cores dominated by iron and siliconLiquid metal hydrogen(where molecules dissociate into independent atoms to form conductive fluid), liquidMolecular hydrogen。The core temperature can reach 30000K.The atmosphere is above 71370km.
The distribution of clouds in Jupiter's atmosphere has the following characteristics: the outermost layer is ammonia crystal cloud, the temperature is 150K, and the earth's atmospheric pressure is about 0.6;About 30km below it is ammonia hydrogen sulfide crystal cloud, with a temperature of 200K and a pressure of about 1.7 Earth atmospheres;35 kilometers further down, there is a water ice crystal cloud layer with a temperature of about 250K and a pressure of about 4-5 Earth atmospheres.Below this layer, the temperature is above 270K, and water drops begin to appear.Above the outermost ammonia crystal cloud, the temperature decreases with height and starts to increase with height after reaching the lowest value of 110K.Observing Jupiter with a telescope, its cloud layer looks like a zebra stripe of light and dark stripes. Traditionally, the light stripes are called stripes, and the dark stripes are called stripes, both parallel to the equator. The light stripes are mainly white or grayish yellow, while the dark stripes are reddish brown with different depths.The brightness of bands and stripes varies with time. Dark areas can appear in bright bands and bright areas can also be observed in dark stripes.In addition, there is a large red spot in the southern hemisphere, which is egg shaped, about 14000km wide and 30000-40000 km long, as big as three Earths.Jupiter's atmosphere moves very intensely. According to the analysis of infrared detection data, the bright belt is formed by rising warm air flow, which is a high pressure belt (similar to the "high pressure" in the Earth's atmosphere);The dark streaks are composed of cooler downdrafts, which are low pressure zones (similar to the "low pressure" in the earth's atmosphere).The cloud top of the bright band is much higher than that of the dark stripe, and the temperature of the former is about 15K lower than that of the latter.The main components of Jupiter's atmosphere are colorless, with only trace colored substances such as sulfur, red phosphorus or some organic molecules.The crystals in the clouds are all white.The appearance of color difference on Jupiter may be the result of chemical reaction of light colored compounds on the top of the bright band due to solar ultraviolet radiation, generating dark colored compounds, which gather in the dark stripes due to cooling and sinking.
On Jupiter, as on Earth, the wind blows from the high pressure area to the low pressure area, and is affected by theCoriolis force(SeeForces in the atmosphere）As the high pressure zone and low pressure zone on Jupiter form a ring belt (i.e. bright belt and dark stripe), in the Northern Hemisphere, the north side of the high pressure zone (bright belt) blows westerly, and the south side blows easterly;East wind is blowing on the north side of the low-pressure zone (dark stripe), and west wind is blowing on the south side.The opposite is true in the southern hemisphere.Both hemispheres have many east-west wind belts that intersect each other (see figure). Strong westerlies prevail in a wide range on both sides of the equator. The wind speed can reach 150 m/s. At higher latitudes, the wind speed decreases.The cloud layer, shape and color in Jupiter's atmosphere are constantly changing, but the wind belt of zonal circulation, regardless of position or intensity, is rarely changed.Some have permanent or semi permanent movement characteristics, even lasting for several years, decades to hundreds of years.Great erythemaThis is one example.It is located in a high pressure central area of the high pressure zone in the southern hemispheretyphoonSimilar huge storm, rotating counterclockwise for about 6 days at a time（Earth time）。The warm air inside it rises strongly. The cloud top of the Great Red Spot is about several kilometers higher than the surrounding cloud top. The airflow contains red phosphorus compounds, which may be red orange.Others believe that due to the sharp rise of the air flow, a huge thunderstorm cloud anvil has been formed, and this huge discharge phenomenon covering tens of millions of square kilometers shows a big red spot.The interaction between the Great Red Spot circulation and the ambient air flow at its southern and northern edges can also cause complex disturbance flow patterns.In the southeast of the large erythema, egg shaped small white spots were observed.In the Northern Hemisphere, some brown elliptical disturbances with an average life of 1 to 2 years are also observed, which are called small erythema.Its properties are similar to those of erythema magna.In addition, a thin ring of material around Jupiter was observed about 55000km above the cloud top, with a thickness of less than 1km and a radial range of about 6000km.The energy radiated into space by Jupiter is 2.5 times of the heat it absorbs from the sun, which indicates that there is a heat source inside Jupiter. This heat source may be caused by the transformation of gravitational potential energy into heat energy when the planet was initially formed, and it is transferred to the surface by the large-scale convection of liquid hydrogen.From this point of view, the energy of Jupiter's atmospheric movement may be supplied by Jupiter's own heat energy.[2]
Jupiter is the largest planet in the solar system. It has a huge atmosphere, which can be divided into the troposphere, stratosphere, mesosphere and thermosphere. There are clouds in Jupiter's atmosphere. The main features of Jupiter's appearance are cloud bands, zonal airflow and large red spots.The main components are hydrogen and helium.[3][9]
Saturns atmosphere
The main components are hydrogen and helium, and contain ammonia, methane and other gases.
The volume of Saturn is about 745 times of that of the Earth, and its mass is about 95.18 times of that of the Earth. Its average density is only 1/8 of that of the Earth (0.70g/cm3)Nine planetsMedium density is the smallest.It is generally believed that Saturn has a rock core with a thick ice shellMetallic hydrogenLayer, liquid molecular hydrogen layer, above this liquid layer, there is atmosphere.The upper layer of Saturn's atmosphere is often covered by dense ammonia crystal clouds. Until now, people have not been able to see the lower layer of clouds and understand the state of the lower atmosphere.The ammonia crystal cloud presents colorful bright bands and dark lines, which are parallel to the equator, but its color is not as bright as Jupiter.The color is mainly golden yellow, and the rest are orange and light yellow. However, the polar region is green, which is the darkest region in the entire Saturn image.The result of infrared detection: the cloud top temperature is 103K, and the surface temperature is about 133K.US launchedSaturn probePioneer 11 It is also found that Saturn has a broad ionosphere composed of ionized hydrogen, and its upper layer temperature is about 1250K.A. of Harvard Smithsonian Center for AstrophysicsF. Cook, analyzing in the spring of 1981Voyager 1After the exploration data of, it is found that there is a haze layer about 60km thick about 150km above the dense ammonia crystal cloud, which only exists in some isolated areas and does not connect into large areas.In this haze layer, no convective disturbance from the lower layer is found.Voyager 1's exploration in August 1980 also found a red spot in Saturn's southern hemisphere, similar to Jupiter's Great Red Spot.It is oval, about 10000 kilometers long, and only 1/3 the diameter of Jupiter's Great Red Spot.Then, a few days before the closest approach to Saturn in November 1980, the probe further found that the red spot was surrounded by a black ring.According to preliminary research, it is a hugeAnticyclonestorm.In addition, Voyager 1 also photographed some strange bright white spots on the top of Saturn's cloud layer, while in Saturn's northern hemisphere, it photographed other such oval patches, as well as light colored, small-scale convective cloud patterns and a wave line thousands of kilometers long.These observations of Voyager 1 show that the wind speed of Saturn's equatorial wind belt is very high, up to 500 meters per second, about 3 to 4 times the speed of Jupiter's equatorial wind belt, and the width of this equatorial wind belt is also much larger than Jupiter's, extending to 40 ° north and south latitudes respectively.The kinetic energy of Saturn's wind may be 16 times that of Jupiter.British GE. Hunter believes that this is because the ammonia cloud layer on Saturn is thicker than Jupiter, and the temperature is also lower. The extra heat released when they condense causes more energy to join the vortex, accelerating and driving the zonal wind on the equator, so the wind speed is larger and the width of the wind band is larger.Another view is that Saturn has internal energy, and the energy it radiates is about 4.5 times of the solar heat it absorbs, which may cause its equatorial wind to carry greater wind speed and energy.[4]
The upper atmosphere of Saturn is often covered by dense ammonia crystal clouds, which are parallel to the equator with colorful bright bands and dark stripes.[3]Saturn's outer atmosphere contains 96.3% molecular hydrogen and 3.25% helium by volume.[10]
Uranus atmosphere, Neptune atmosphere and Pluto atmosphere
Uranus's atmosphere is mainly composed of hydrogen, helium and methane[10]The main components of Neptune's atmosphere are nitrogen and methane, as well as a small amount of atmosphere.These two planets have a denser atmosphere and thicker clouds.[3]
Uranus and Neptune may have the same structure, both have rock cores, and the core temperature can reach 2000-3000K. Outside the rock core is a massive ice layer. Outside the ice layer, there is a dense atmosphere, including very thick clouds.The atmosphere is mainly composed of hydrogen, andmethaneAnd a small amount of helium and ammonia.The surface temperatures of Uranus and Neptune are both about 70K. The clouds of these two planets are mainly methane clouds and ammonia clouds.Pluto's surface temperature is about 60K. If there is an atmosphere, it can only be hydrogen, helium, neon, etc.These planets are far from the earth, and many features cannot be observed with telescopes.American SpacecraftVoyager 2He is flying in space, and is expected to visit Uranus and Neptune successively in 1986 and 1989. It is expected that more exploration data will be obtained at that time, which will help to understand them.
Mercurian atmosphere
Mercury's atmosphere Mercury's gravitational weight is small, and gas particles are easy to escape from Mercury's gravitational field.Therefore, there is only one extremely thin atmosphere, and its surface atmospheric pressure is only equivalent to the atmospheric pressure 500 kilometers above the earth's atmosphere.[3]
Satellite atmosphere
Some satellites of planets in the solar system also have atmospheres. For example, Titan, the largest planet in Saturn, has a dense atmosphere. It is the only satellite in the solar system with a rich atmosphere. The surface atmospheric pressure is about 1.5 × 105 Pa, which is much denser than the earth's atmosphere.Titan's atmosphere is mainly composed of nitrogen, followed by methane, nitrogen, nitrogen, etc. There are clouds over Titan. In addition, Io and Ganymede also have thin atmosphere, and Io's atmosphere is mainly composed ofsulfur dioxideThe main components of Ganymede's atmosphere are methane and atmosphere.[5]
Application and influence
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(1) It can be used for natural disaster prediction;[6]
(2) It can be used for the planetary exploration mission;[7]
The study of planetary atmosphere is of great significance for understanding the change trend of the Earth's atmosphere and protecting the living environment of mankind. Chinese scholars have studied the impact of early condensation, radiation, atmospheric escape and greenhouse effect on the planetary atmosphere and surface thermal state,It is proposed that the origin of the earth's atmosphere should have a primary primitive atmospheric stage. Its main feature is the reduced atmosphere rich in hydrogen and its compounds. The Martian dust storm is a unique phenomenon of Mars. Based on the analysis of the impact of the Martian terrain on the Martian atmosphere, it is proposed that the Martian dust storm is formed by the strong ground wind speed and updraft caused by the vortex caused by the Martian terrain.[8]
