Mars' Atmosphere: Composition, Climate & Weather Mars' Atmosphere: Composition, Climate & Weather By Tim Sharp, Reference Editor | August 3, 2012 02:50pm ET MORE The thin atmosphere of Mars today composed mainly of carbon dioxide as depicted in this artist's illustration Credit: NASA Mars has a thin atmosphere — too thin to easily support life as we know it. The extremely thin air on Mars can also become very dusty. Giant dust storms can blanket the entire planet and last for months. What is Mars' atmosphere made of? The atmosphere of Mars is about 100 times thinner than Earth's, and it is 95 percent carbon dioxide.

Here's a breakdown of its composition: Carbon dioxide: 95.32 percent Also, minor amounts of: water, nitrogen oxide, neon, hydrogen-deuterium-oxygen, krypton and xenon Climate and weather Mars' thin atmosphere and its greater distance from the sun mean that Mars is much colder than Earth The average temperature is about minus 80 degrees F (minus 60 degrees C), although it can vary from minus 195 degrees F (minus 125 degrees C) near the poles during the winter to as much as a comfortable 70 degrees F (20 degrees C) at midday near the equator. The atmosphere of Mars is also roughly 100 times thinner than Earth's, but it is still thick enough to support weather, clouds and winds. Giant dust devils routinely kick up the oxidized iron dust that covers Mars' surface. The dust storms of Mars are the largest in the solar system , capable of blanketing the entire planet and lasting for months. One theory as to why dust storms can grow so big on Mars starts with airborne dust particles absorbing sunlight, warming the Martian atmosphere in their vicinity. Warm pockets of air flow toward colder regions, generating winds.

Strong winds lift more dust off the ground, which in turn heats the atmosphere, raising more wind and kicking up more dust. At times, it even snows on Mars . The Martian snowflakes, made of carbon dioxide rather than water, are thought to be about the size of red blood cells. The north and south polar regions of Mars are capped by ice, much of it made from carbon dioxide, not water. Possibility of life Mars could have once harbored life. Some conjecture that life might still exist there today. A number of researchers have even speculated that life on Earth might have seeded Mars , or that life on Mars seeded Earth . Oceans may have covered the surface of Mars in the past, providing an environment for life to develop. Although the red planet is a cold desert today, researchers suggest that liquid water may be present underground, providing a potential refuge for any life that might still exist there. Several studies have shown that there is abundant water ice beneath the surface.

Related: NASA - The Five Most Abundant Gases in the Martian Atmosphere › Full Size › 800 x 600 The Five Most Abundant Gases in the Martian Atmosphere This graph shows the percentage abundance of five gases in the atmosphere of Mars, as measured by the Quadrupole Mass Spectrometer instrument of the Sample Analysis at Mars instrument suite on NASA's Mars rover in October 2012. The season was early spring in Mars' southern hemisphere, and the location was inside Mars' Gale Crater, at 4.49 degrees south latitude, 137.42 degrees east longitude. The graph uses as logarithmic scale for volume percentage of the atmosphere so that these gases with very different concentrations can all be plotted. By far the predominant gas is carbon dioxide, making up 95.9 percent of the atmosphere's volume. The next four most abundant gases are argon, nitrogen, oxygen and carbon monoxide. Researchers will use SAM repeatedly throughout Curiosity's mission on Mars to check for seasonal changes in atmospheric composition.

Image Credit: NASA/JPL-Caltech, SAM/GSFC Atmosphere of Mars: Planet Mars Atmospheric Pressure, Layers & Sky – PlanetFacts.org The Moon The Atmosphere of Mars Mars’ atmosphere is thinner compared to that of earth. The atmospheric pressure on Mars depends on how high or low the land is elevated. On Olympus Mon’s peak, Its pressure is at 30 pascals (0.0044 psi) and in the lowest point of Hellas Planitia it can get as high as 1,155 pascals (0.1675 psi). Its average pressure would be 600 pascals (0.087 psi). The scale height of Mar’s atmosphere is around 6.8 miles (11 km). Carbon Dioxide makes up the predominant gas in Mar’s atmosphere. It makes up about 95% of the atmosphere with other gasses like nitrogen composing 3%. Argon makes up 1.6% and the remaining percentages make up traces of water, oxygen and methane. The existence of methane has led some scientists to believe that some forms of life exist on mars. Dust fills the atmosphere so the sky above mars has a rusty color.

Mars’ atmosphere is composed of four regions, the Lower Atmosphere, Middle Atmosphere, Upper Atmosphere and the Exosphere. The Lower Atmosphere is warm because it is affected by the heat from the ground and from airborne dust. The Middle Atmosphere is composed of a jet stream. The Upper Atmosphere is also known as the Thermosphere. The temperature in this region is very high because of heating from the sun. The gasses in this part of the atmosphere separate. The Exosphere starts at 200 kilometers (120 mi) above. This is where mars atmosphere stops and space begins. Evidence has been found to suggest that the atmosphere of Mars has changed over the course of a few billion years. The Mars Ocean Hypothesis even goes so far as to suggest that Mars was once made up entirely of water due to the current atmospheric pressure found in Mars today. At the moment only solid and vapor forms of water may exist on the higher parts of Mars. There was once a time when Mars was conducive to hold water but that changed due changing factors. Something about Mars Tholzel Why not? “Life” follows the same rules everywhere in the Universe. But not to worry.

The only possible “life” on Mars would be some very simple, very rugged bacteria. Porfirio Cantu Jr. I don’t begin to understand how comparing human life to mars applies. Two distinct planets with two distinct evolutionary paths. If life exists there it would in no way or form resemble ours. Snow Angel The person before me is a idiot because they dont know how to frecking spell and so does the briane.I mean duhhhhhhh people they are like in Elematry school duuhhhhhhhh. Idoits I hope you are reading this it on the web duhhhhhhhhhhhhhhhhhhhhhhhhhh. Soooo bye!!!!!!!!!!!!! What Is Mars Atmosphere Made Of - Universe Today Universe Today What Is Mars Atmosphere Made Of Article Updated: 24 Dec , 2015 by Jerry Coffey [/caption]I think that one of the most interesting questions that have been posed of late is ‘what is Mar’s atmosphere made of?’ There has been a great deal of study done on this topic and interest is increasing since the discovery of methane, a possible indicator of life.

The atmosphere of Mars is over 95% carbon dioxide, 95.32% to be exact. The breakdown of gases goes like this: Carbon dioxide 95.32% Nitric oxide .0013% Trace gases(including krypton, methane, etc) The Martian atmosphere has four main layers: lower, middle, upper, and exosphere. The lower atmosphere is a warm region(around 210 K). It is warmed by airborne dust(1.5 micrometers across) and heat radiated from the surface. This airborne dust gives the planet its ruddy brown appearance. The middle atmosphere is features a jetstream similar to Earth’s. The upper atmosphere is heated by the solar wind and the temperatures are much higher than at the surface. This heat separates the gases. The exosphere starts at about 200 km and has no clear end. It just tapers off into space. The carbon dioxide in the atmosphere freezes for part of the year and may drop to the surface. As much as 25% of the atmospheric carbon dioxide condenses at the polar caps into solid ice(dry ice) because the Martian poles are not exposed to sunlight during the planet’s winter.

When the poles are again exposed to sunlight, the ice returns to its gas form and rises back into the atmosphere. So, a significant annual variation in the atmospheric pressure and atmospheric composition around the Martian poles. The methane mentioned earlier is used to show the possibility of life on Mars. While it is a byproduct of life, it is also a result of volcanism, geothermal process, and hydrothermal activity. Methane is an unstable gas, so there has to be a source on the planet that is constantly replenishing it. It has to be a very active source, because studies have shown that the methane is destroyed in less than on Earth year. It is thought that peroxides and perchlorates in the soil or that it condenses and evaporates seasonally from clathrates. Now you answer ‘ what is Mar’s atmosphere made of?’ the next time it comes up. You can be sure that the methane component will continue to be studied by rovers, orbiters, and, in the future, astronauts. We have written many articles about the atmosphere of Mars for Universe Today. Here’s an article about the air on Mars , and here’s an article about Mars’ comparison with Earth .

If you’d like more info on Mars, check out Hubblesite’s News Releases about Mars , and here’s a link to the NASA Mars Exploration home page . We’ve also recorded an episode of Astronomy Cast all about Mars. Listen here, Episode 52: Mars . Reference: What Is The Atmosphere Like On Other Planets? - Universe Today Universe Today What Is The Atmosphere Like On Other Planets? Article Updated: 5 Jul , 2016 by Matt Williams Here on Earth, we tend to take our atmosphere for granted, and not without reason. Our atmosphere has a lovely mix of nitrogen and oxygen (78% and 21% respectively) with trace amounts of water vapor, carbon dioxide and other gaseous molecules. What’s more, we enjoy an atmospheric pressure of 101.325 kPa, which extends to an altitude of about 8.5 km. In short, our atmosphere is plentiful and life-sustaining. But what about the other planets of the Solar System? How do they stack up in terms of atmospheric composition and pressure? We know for a fact that they are not breathable by humans and cannot support life.

But just what is the difference between these balls of rock and gas and our own? For starters, it should be noted that every planet in the Solar System has an atmosphere of one kind or another. And these range from incredibly thin and tenuous (such as Mercury’s “exosphere”) to the incredibly dense and powerful – which is the case for all of the gas giants. And depending on the composition of the planet, whether it is a terrestrial or a gas/ice giant, the gases that make up its atmosphere range from either the hydrogen and helium to more complex elements like oxygen, carbon dioxide, ammonia and methane. Mercury’s Atmosphere: Mercury is too hot and too small to retain an atmosphere. However, it does have a tenuous and variable exosphere that is made up of hydrogen, helium, oxygen, sodium, calcium, potassium and water vapor, with a combined pressure level of about 10-14 bar (one-quadrillionth of Earth’s atmospheric pressure). It is believed this exosphere was formed from particles captured from the Sun, volcanic outgassing and debris kicked into orbit by micrometeorite impacts. A High-resolution Look over Mercury’s Northern Horizon.

Credit: NASA/MESSENGER Because it lacks a viable atmosphere, Mercury has no way to retain the heat from the Sun. As a result of this and its high eccentricity, the planet experiences considerable variations in temperature. Whereas the side that faces the Sun can reach temperatures of up to 700 K (427° C), while the side in shadow dips down to 100 K (-173° C). Venus’ Atmosphere: Surface observations of Venus have been difficult in the past, due to its extremely dense atmosphere, which is composed primarily of carbon dioxide with a small amount of nitrogen. At 92 bar (9.2 MPa), the atmospheric mass is 93 times that of Earth’s atmosphere and the pressure at the planet’s surface is about 92 times that at Earth’s surface. Venus is also the hottest planet in our Solar System, with a mean surface temperature of 735 K (462 °C/863.6 °F). This is due to the CO²-rich atmosphere which, along with thick clouds of sulfur dioxide, generates the strongest greenhouse effect in the Solar System.

Above the dense CO² layer, thick clouds consisting mainly of sulfur dioxide and sulfuric acid droplets scatter about 90% of the sunlight back into space. Another common phenomena is Venus’ strong winds, which reach speeds of up to 85 m/s (300 km/h; 186.4 mph) at the cloud tops and circle the planet every four to five Earth days. At this speed, these winds move up to 60 times the speed of the planet’s rotation, whereas Earth’s fastest winds are only 10-20% of the planet’s rotational speed. Venus flybys have also indicated that its dense clouds are capable of producing lightning , much like the clouds on Earth. Their intermittent appearance indicates a pattern associated with weather activity, and the lightning rate is at least half of that on Earth. Earth’s Atmosphere: Earth’s atmosphere, which is composed of nitrogen, oxygen, water vapor, carbon dioxide and other trace gases, also consists of five layers. These consists of the Troposphere, the Stratosphere, the Mesosphere, the Thermosphere, and the Exosphere.

As a rule, air pressure and density decrease the higher one goes into the atmosphere and the farther one is from the surface. Closest to the Earth is the Troposphere, which extends from the 0 to between 12 km and 17 km (0 to 7 and 10.56 mi) above the surface. This layer contains roughly 80% of the mass of Earth’s atmosphere, and nearly all atmospheric water vapor or moisture is found in here as well. As a result, it is the layer where most of Earth’s weather takes place. The Stratosphere extends from the Troposphere to an altitude of 50 km (31 mi). This layer extends from the top of the troposphere to the stratopause, which is at an altitude of about 50 to 55 km (31 to 34 mi). This layer of the atmosphere is home to the ozone layer, which is the part of Earth’s atmosphere that contains relatively high concentrations of ozone gas. Space Shuttle Endeavour sillouetted against the atmosphere. The orange layer is the troposphere, the white layer is the stratosphere and the blue layer the mesosphere.

Credit: NASA Next is the Mesosphere, which extends from a distance of 50 to 80 km (31 to 50 mi) above sea level. It is the coldest place on Earth and has an average temperature of around -85 °C (-120 °F; 190 K). The Thermosphere, the second highest layer of the atmosphere, extends from an altitude of about 80 km (50 mi) up to the thermopause, which is at an altitude of 500–1000 km (310–620 mi). The lower part of the thermosphere, from 80 to 550 kilometers (50 to 342 mi), contains the ionosphere – which is so named because it is here in the atmosphere that particles are ionized by solar radiation. This layer is completely cloudless and free of water vapor. It is also at this altitude that the phenomena known as Aurora Borealis and Aurara Australis are known to take place.

The Exosphere, which is outermost layer of the Earth’s atmosphere, extends from the exobase – located at the top of the thermosphere at an altitude of about 700 km above sea level – to about 10,000 km (6,200 mi). The exosphere merges with the emptiness of outer space, and is mainly composed of extremely low densities of hydrogen, helium and several heavier molecules including nitrogen, oxygen and carbon dioxide The exosphere is located too far above Earth for any meteorological phenomena to be possible. However, the Aurora Borealis and Aurora Australis sometimes occur in the lower part of the exosphere, where they overlap into the thermosphere. Photo of the aurora taken by astronaut Doug Wheelock from the International Space Station on July 25, 2010. Credit: NASA/Johnson Space Center The average surface temperature on Earth is approximately 14°C; but as already noted, this varies. For instance, the hottest temperature ever recorded on Earth was 70.7°C (159°F), which was taken in the Lut Desert of Iran.

Meanwhile, the coldest temperature ever recorded on Earth was measured at the Soviet Vostok Station on the Antarctic Plateau, reaching an historic low of -89.2°C (-129°F). Mars’ Atmosphere: Planet Mars has a very thin atmosphere which is composed of 96% carbon dioxide, 1.93% argon and 1.89% nitrogen along with traces of oxygen and water. The atmosphere is quite dusty, containing particulates that measure 1.5 micrometers in diameter, which is what gives the Martian sky a tawny color when seen from the surface. Mars’ atmospheric pressure ranges from 0.4 – 0.87 kPa, which is equivalent to about 1% of Earth’s at sea level. Because of its thin atmosphere, and its greater distance from the Sun, the surface temperature of Mars is much colder than what we experience here on Earth.

The planet’s average temperature is -46 °C (51 °F), with a low of -143 °C (-225.4 °F) during the winter at the poles, and a high of 35 °C (95 °F) during summer and midday at the equator. The planet also experiences dust storms, which can turn into what resembles small tornadoes. Larger dust storms occur when the dust is blown into the atmosphere and heats up from the Sun. The warmer dust filled air rises and the winds get stronger, creating storms that can measure up to thousands of kilometers in width and last for months at a time. When they get this large, they can actually block most of the surface from view. Mars, as it appears today, with a very thin and tenuous atmosphere. Credit: NASA Trace amounts of methane have also been detected in the Martian atmosphere, with an estimated concentration of about 30 parts per billion (ppb).

It occurs in extended plumes, and the profiles imply that the methane was released from specific regions – the first of which is located between Isidis and Utopia Planitia (30°N 260°W) and the second in Arabia Terra (0°N 310°W). Ammonia was also tentatively detected on Mars by the Mars Express satellite, but with a relatively short lifetime. It is not clear what produced it, but volcanic activity has been suggested as a possible source. Jupiter’s Atmosphere: Much like Earth, Jupiter experiences auroras near its northern and southern poles. But on Jupiter, the auroral activity is much more intense and rarely ever stops. The intense radiation, Jupiter’s magnetic field, and the abundance of material from Io’s volcanoes that react with Jupiter’s ionosphere create a light show that is truly spectacular. Jupiter also experiences violent weather patterns . Wind speeds of 100 m/s (360 km/h) are common in zonal jets, and can reach as high as 620 kph (385 mph). Storms form within hours and can become thousands of km in diameter overnight.

One storm, the Great Red Spot , has been raging since at least the late 1600s. The storm has been shrinking and expanding throughout its history; but in 2012, it was suggested that the Giant Red Spot might eventually disappear . Jupiter is perpetually covered with clouds composed of ammonia crystals and possibly ammonium hydrosulfide. These clouds are located in the tropopause and are arranged into bands of different latitudes, known as “tropical regions”. The cloud layer is only about 50 km (31 mi) deep, and consists of at least two decks of clouds: a thick lower deck and a thin clearer region. There may also be a thin layer of water clouds underlying the ammonia layer, as evidenced by flashes of lightning detected in the atmosphere of Jupiter, which would be caused by the water’s polarity creating the charge separation needed for lightning. Observations of these electrical discharges indicate that they can be up to a thousand times as powerful as those observed here on the Earth. Saturn’s Atmosphere: The outer atmosphere of Saturn contains 96.3% molecular hydrogen and 3.25% helium by volume.

The gas giant is also known to contain heavier elements, though the proportions of these relative to hydrogen and helium is not known. It is assumed that they would match the primordial abundance from the formation of the Solar System. Trace amounts of ammonia, acetylene, ethane, propane, phosphine and methane have been also detected in Saturn’s atmosphere. The upper clouds are composed of ammonia crystals , while the lower level clouds appear to consist of either ammonium hydrosulfide (NH4SH) or water . Ultraviolet radiation from the Sun causes methane photolysis in the upper atmosphere, leading to a series of hydrocarbon chemical reactions with the resulting products being carried downward by eddies and diffusion. Saturn’s atmosphere exhibits a banded pattern similar to Jupiter’s, but Saturn’s bands are much fainter and wider near the equator. As with Jupiter’s cloud layers, they are divided into the upper and lower layers, which vary in composition based on depth and pressure. In the upper cloud layers, with temperatures in range of 100–160 K and pressures between 0.5–2 bar, the clouds consist of ammonia ice.

Water ice clouds begin at a level where the pressure is about 2.5 bar and extend down to 9.5 bar, where temperatures range from 185–270 K. Intermixed in this layer is a band of ammonium hydrosulfide ice, lying in the pressure range 3–6 bar with temperatures of 290–235 K. Finally, the lower layers, where pressures are between 10–20 bar and temperatures are 270–330 K, contains a region of water droplets with ammonia in an aqueous solution. On occasion, Saturn’s atmosphere exhibits long-lived ovals, similar to what is commonly observed on Jupiter. Whereas Jupiter has the Great Red Spot, Saturn periodically has what’s known as the Great White Spot (aka. Great White Oval). This unique but short-lived phenomenon occurs once every Saturnian year, roughly every 30 Earth years, around the time of the northern hemisphere’s summer solstice. These spots can be several thousands of kilometers wide, and have been observed in 1876, 1903, 1933, 1960, and 1990.

Since 2010, a large band of white clouds called the Northern Electrostatic Disturbance have been observed enveloping Saturn, which was spotted by the Cassini space probe. If the periodic nature of these storms is maintained, another one will occur in about 2020. The winds on Saturn are the second fastest among the Solar System’s planets, after Neptune’s. Voyager data indicate peak easterly winds of 500 m/s (1800 km/h). Saturn’s northern and southern poles have also shown evidence of stormy weather. At the north pole, this takes the form of a hexagonal wave pattern, whereas the south shows evidence of a massive jet stream. The persisting hexagonal wave pattern around the north pole was first noted in the Voyager images. The sides of the hexagon are each about 13,800 km (8,600 mi) long (which is longer than the diameter of the Earth) and the structure rotates with a period of 10h 39m 24s, which is assumed to be equal to the period of rotation of Saturn’s interior.

The south pole vortex, meanwhile, was first observed using the Hubble Space Telescope . These images indicated the presence of a jet stream, but not a hexagonal standing wave. These storms are estimated to be generating winds of 550 km/h, are comparable in size to Earth, and believed to have been going on for billions of years. In 2006, the Cassini space probe observed a hurricane-like storm that had a clearly defined eye. Such storms had not been observed on any planet other than Earth – even on Jupiter. Uranus’ Atmosphere: As with Earth, the atmosphere of Uranus is broken into layers, depending upon temperature and pressure. Like the other gas giants, the planet doesn’t have a firm surface, and scientists define the surface as the region where the atmospheric pressure exceeds one bar (the pressure found on Earth at sea level). Anything accessible to remote-sensing capability – which extends down to roughly 300 km below the 1 bar level – is also considered to be the atmosphere. Diagram of the interior of Uranus. Credit: Public Domain Using these references points, Uranus’ atmosphere can be divided into three layers.

The first is the troposphere, between altitudes of -300 km below the surface and 50 km above it, where pressures range from 100 to 0.1 bar (10 MPa to 10 kPa). The second layer is the stratosphere, which reaches between 50 and 4000 km and experiences pressures between 0.1 and 10-10 bar (10 kPa to 10 µPa). The troposphere is the densest layer in Uranus’ atmosphere. Here, the temperature ranges from 320 K (46.85 °C/116 °F) at the base (-300 km) to 53 K (-220 °C/-364 °F) at 50 km, with the upper region being the coldest in the solar system . The tropopause region is responsible for the vast majority of Uranus’s thermal infrared emissions, thus determining its effective temperature of 59.1 ± 0.3 K. Within the troposphere are layers of clouds – water clouds at the lowest pressures, with ammonium hydrosulfide clouds above them.

Ammonia and hydrogen sulfide clouds come next. Finally, thin methane clouds lay on the top. In the stratosphere, temperatures range from 53 K (-220 °C/-364 °F) at the upper level to between 800 and 850 K (527 – 577 °C/980 – 1070 °F) at the base of the thermosphere, thanks largely to heating caused by solar radiation. The stratosphere contains ethane smog, which may contribute to the planet’s dull appearance. Acetylene and methane are also present, and these hazes help warm the stratosphere. Uranus, as imaged by the Hubble Space Telescope. Image credit: NASA/Hubble The outermost layer, the thermosphere and corona, extend from 4,000 km to as high as 50,000 km from the surface. This region has a uniform temperature of 800-850 (577 °C/1,070 °F), although scientists are unsure as to the reason.

Because the distance to Uranus from the Sun is so great, the amount of sunlight absorbed cannot be the primary cause. Like Jupiter and Saturn, Uranus’s weather follows a similar pattern where systems are broken up into bands that rotate around the planet, which are driven by internal heat rising to the upper atmosphere. As a result, winds on Uranus can reach up to 900 km/h (560 mph), creating massive storms like the one spotted by the Hubble Space Telescope in 2012. Similar to Jupiter’s Great Red Spot, this “ Dark Spot ” was a giant cloud vortex that measured 1,700 kilometers by 3,000 kilometers (1,100 miles by 1,900 miles). Neptune’s Atmosphere: At high altitudes, Neptune’s atmosphere is 80% hydrogen and 19% helium, with a trace amount of methane. As with Uranus, this absorption of red light by the atmospheric methane is part of what gives Neptune its blue hue, although Neptune’s is darker and more vivid. Because Neptune’s atmospheric methane content is similar to that of Uranus, some unknown constituent is thought to contribute to Neptune’s more intense coloring.

Neptune’s atmosphere is subdivided into two main regions: the lower troposphere (where temperature decreases with altitude), and the stratosphere (where temperature increases with altitude). The boundary between the two, the tropopause, lies at a pressure of 0.1 bars (10 kPa). The stratosphere then gives way to the thermosphere at a pressure lower than 10-5 to 10-4 microbars (1 to 10 Pa), which gradually transitions to the exosphere. Neptune’s spectra suggest that its lower stratosphere is hazy due to condensation of products caused by the interaction of ultraviolet radiation and methane (i.e. photolysis), which produces compounds such as ethane and ethyne. The stratosphere is also home to trace amounts of carbon monoxide and hydrogen cyanide, which are responsible for Neptune’s stratosphere being warmer than that of Uranus. A modified color/contrast image emphasizing Neptune’s atmospheric features, including wind speed. Credit Erich Karkoschka) For reasons that remain obscure, the planet’s thermosphere experiences unusually high temperatures of about 750 K (476.85 °C/890 °F).

The planet is too far from the Sun for this heat to be generated by ultraviolet radiation, which means another heating mechanism is involved – which could be the atmosphere’s interaction with ion’s in the planet’s magnetic field, or gravity waves from the planet’s interior that dissipate in the atmosphere. Because Neptune is not a solid body, its atmosphere undergoes differential rotation. The wide equatorial zone rotates with a period of about 18 hours, which is slower than the 16.1-hour rotation of the planet’s magnetic field. By contrast, the reverse is true for the polar regions where the rotation period is 12 hours. This differential rotation is the most pronounced of any planet in the Solar System, and results in strong latitudinal wind shear and violent storms. The three most impressive were all spotted in 1989 by the Voyager 2 space probe, and then named based on their appearances. The first to be spotted was a massive anticyclonic storm measuring 13,000 x 6,600 km and resembling the Great Red Spot of Jupiter. Known as the Great Dark Spot , this storm was not spotted five later (Nov.

2nd, 1994) when the Hubble Space Telescope looked for it. Instead, a new storm that was very similar in appearance was found in the planet’s northern hemisphere, suggesting that these storms have a shorter life span than Jupiter’s. Reconstruction of Voyager 2 images showing the Great Black spot (top left), Scooter (middle), and the Small Black Spot (lower right). Credit: NASA/JPL The Scooter is another storm, a white cloud group located farther south than the Great Dark Spot – a nickname that first arose during the months leading up to the Voyager 2 encounter in 1989. The Small Dark Spot , a southern cyclonic storm, was the second-most-intense storm observed during the 1989 encounter. It was initially completely dark; but as Voyager 2 approached the planet, a bright core developed and could be seen in most of the highest-resolution images. In sum, the planet’s of our Solar System all have atmospheres of sorts. And compared to Earth’s relatively balmy and thick atmosphere, they run the gamut between very very thin to very very dense. They also range in temperatures from the extremely hot (like on Venus) to the extreme freezing cold.

And when it comes to weather systems, things can equally extreme, with planet’s boasting either weather at all, or intense cyclonic and dust storms that put storms here n Earth to shame. And whereas some are entirely hostile to life as we know it, others we might be able to work with. We have many interesting articles about planetary atmosphere’s here at Universe Today. For instance, he’s What is the Atmosphere? , and articles about the atmosphere of Mercury , Venus , Mars , Jupiter , Saturn , Uranus and Neptune , Mars: Lower Atmosphere - Windows to the Universe Image of Dust Storms Lower Atmosphere The atmosphere of Mars is much thinner than that of Earth, with a surface pressure averaging 1/100th that at the surface of the Earth. Surface temperatures range from -113oC at the winter pole to 0oC on the dayside during summer. Although the length of the Martian day (24 hours and 37 minutes) and the tilt of its axis (25 degrees) are similar to those on Earth (24 hours and 23.5 degrees), the orbit of the planet about the Sun affects the lengths of the seasons the most.

The atmosphere is composed mainly of carbon dioxide (95.3%), nitrogen (2.7%), and argon (1.6%), with small amounts of other gases. Oxygen, which is so important to us on earth, makes up only 0.13% of the atmosphere at Mars. There is only one-fourth as much water vapor in the atmosphere. Although small, this is thought to be enough to allow water ice to be frozen into the surface of the planet. With so little water, clouds are rarely seen in the Martian sky. The possible role in the past of liquid water in forming the dry river beds which we can see is still unknown, particularly because water ice is not plentiful on the surface of the planet. Shop Windows to the Universe Science Store! Mars Methane: Geology or Biology? Mars Methane: Geology or Biology? By Andrea Thompson, OurAmazingPlanet Managing Editor | January 15, 2009 02:00pm ET MORE Arabia Terra is one of the three equatorial regions where Europe¡¦s Mars Express PFS instrument detected both water vapor and methane concentration. The other two areas are Elysium Planum and Arcadia Memnonia.

Credit: NASA/JPL/Malin Space Science Systems Plumes of methane gas detected over certain locations on Mars in 2003 could point to active geological processes on the red planet, or perhaps even to methane-burping microbes deep below the Martian surface, a new study reports. There is no firm evidence for life on the red planet, however, despite news reports early today suggesting as much. Rather, scientists are puzzled by the new findings. Methane, a small (but important) constituent of Earth's atmosphere, makes up an even smaller percentage of Mars' atmosphere (which is 95 percent carbon dioxide), so detecting it on the red planet is a rare event. In fact, it wasn't detected at all before 2003, when the European Space Agency's Mars Express orbiter (which is still circling the planet) picked up a possible methane signature. A search conducted with three ground-based telescopes that covered 90 percent of the Martian surface over three Mars years (7 Earth years) detected extended plumes of methane that varied with the seasons and seemed to emanate from specific locations. These include the Arabia Terra, Nili Fossae and Syrtis Major regions of Mars.

The work was supported by NASA and the National Science Foundation. In 2005, scientists also found signs of water ice beneath the surface near Mars' equator and, interestingly, near an area where methane has been detected. The methane plumes started to show up in the northern hemisphere spring of Mars, gradually building up and peaking in late summer. At one point during the study, the primary plume contained about 19,000 metric tons (21,000 tons) of methane, comparable to the amount produced at the massive hydrocarbon seep at Coal Pit Point in Santa Barbara, Calif. "It's a heck of a signpost," said study author Michael Mumma of NASA's Goddard Space Flight Center in Greenbelt, Md. Where exactly the methane comes from is still unknown, though scientists have some ideas. Mumma and his team detailed these ideas and their findings in the Jan. 15 early online edition of the journal Science. Geo or bio? The release of methane is likely connected to the heating that happens as summer progresses in the northern hemisphere, Mumma said.

This heat could be melting ice that usually seals up pores or fissures in deep-relief areas such as scarps or craters walls (this is similar to how in the winter here on Earth, the sunny side of the street will have water and slush, while the shady side will stay frozen). The methane in this case would be coming from deeper below the surface. Alternatively, the methane could be released by geochemical processes nearer the surface, within the top meter of the Martian terrain, Mumma said. "We can't really tell the difference at this point," Mumma told SPACE.com. On Earth, one of the main geological processes that releases methane is volcanism, but Mumma said this doesn't look to be the case on Mars because other gases spewed out in much greater amounts by volcanoes haven't been detected. Another possibility is a process called serpentization, which transforms iron oxide into a mineral known as serpentine. The most tantalizing possibility though is that the methane comes from subsurface Martian microbes. Possible Earth analogues are the communities of microorganisms that thrive in gold mines a few kilometers below the surface in the Witwatersrand Basin of South Africa.

The microbes use molecular hydrogen (produced as radioactivity in the surrounding rocks breaks apart water molecules) as an energy source, turning carbon dioxide to methane. Because photosynthesis isn't required, this same process could be taking place below the cryosphere boundary deep below the surface of Mars, where water transitions from ice to liquid water. Of course, Mumma cautions, "we cannot state that we have detected biology or refute it." Meanwhile, Tullis Onstott of Princeton University and colleagues are working on a new device for a potential future rover mission that could trace the origin of the methane . Short-lived Outside of the plumes, methane concentrations were very low, showing that the gas didn't get very far or last very long in the atmosphere. In fact, its lifetime was even shorter than expected or could be explained by the usual method of methane destruction, photolysis (reaction with sunlight). Instead, oxidation (the same process that rusts iron) could be destroying the methane. The Viking landers demonstrated that peroxides were found in the Martian dirt, and the Phoenix Mars lander found evidence for perchlorates , another oxidizer (whether they are found outside of the polar regions is not yet known).

Mumma and his colleagues suggest that peroxide-coated dust grains lofted into the air could be eating away at the methane. The team is planning to do more observations of Mars from ground-based telescopes to see if they find more plumes, as well as whether the previously-observed ones come back again in the summer. "The issue still is was it a sporadic event or is it annual?" Mumma said. But observations from Earth can only tell scientists so much, "ultimately the real test will be to go there," Mumma said. The Mars Science Laboratory rover, now slated to launch in 2011, has the capability to detect methane, but whether or not it will have the chance to is another story. "It may go to a site that is not actively releasing gases," Mumma said. Mars Madness: A Multimedia Adventure! Images: Visualizations of Mars

Question: Which gas makes up 95% of the atmosphere of the planet Mars?
Answer: Carbon Dioxide