What's the climate like on Mars?

Mars is the fourth closest planet to the sun and one of the four terrestrial planets in the solar system. Mars, known as Mars in the west, is the god of war in Roman mythology. In ancient Chinese, it was called "flicker" because it was as bright as fire, and its position and brightness were often unpredictable. Mars is the second smallest planet among the eight planets in the solar system, and its mass and volume are only slightly larger than that of Mercury.

This photo was taken in June of 1976 and operated by Viking 1 Mars probe. The picture shows the thin atmosphere and dusty red surface on the surface of Mars.

Mars is often called "twin earth" because it has many properties with our planet. Are terrestrial planets with polar ice sheets; Moreover, there used to be active atmosphere and liquid water on their respective surfaces. In other respects, there is a big difference between the two. Especially in its own atmosphere and climate, Mars can be said to be completely different from the Earth.

For example, whenever it comes to the weather on Mars, the forecast content is usually very dramatic. Not only is the weather on Mars different from day to day, but sometimes it even changes every hour. This seems a bit unusual for a planet whose surface gas density is only 1% of the earth's atmosphere. But when extreme weather and meteorological phenomena come, Mars actually holds the initiative.

The atmosphere of Mars

The atmosphere of Mars is very thin, including 96% carbon dioxide, 1.93% argon and 1.89% nitrogen, and a small amount of oxygen and water. The air is full of dust, including particles with a diameter of 1.5 micron. It is these particles that have dyed the sky on the surface of Mars yellow-brown. The pressure of Mars is between 0.4 and 0.87 kPa, which is equivalent to 1% of the measured sea level of the earth.

This picture shows the possible ways of methane entering and leaving the atmosphere of Mars.

It is precisely because the atmosphere of Mars is so thin and farther away from the sun that its surface temperature is lower than what we can experience on earth. The average temperature of the earth is only -46 degrees Celsius (-5 1 Fahrenheit), the polar winter temperature is as low as-143 degrees Celsius (-225.4 degrees Fahrenheit), and the equatorial summer noon temperature is as high as 35 degrees Celsius (95 degrees Fahrenheit).

Due to the extremely low temperature in polar regions, 25-30% of carbon dioxide in the air is solidified into dry ice and deposited on the ground. The polar cap of Mars is dominated by water, and the thickness of dry ice in the Arctic can reach one meter in winter. The Antarctic is covered with dry ice up to eight meters thick all year round.

Trace amounts of methane and nitrogen were also detected in the atmosphere of Mars. For the former methane, the estimated concentration is 30ppb in the "Peak Results Monitored by Curiosity Mars Probe" published in February 20 14 and 16. The monitoring data is one-sided, and the source of methane has always been a mystery. Similarly, the source of ammonia cannot be determined. Although volcanic activity may be one of the reasons, it is only a proposal.

Meteorological phenomena:

The violent sandstorm climate on Mars is also very famous, ranging from tornadoes to global sandstorms. Taking the latter as an example, this climate phenomenon is actually that dust is blown into the atmosphere and the temperature rises due to sunlight. Warm dust mixed with air rises, and the wind becomes stronger and stronger, thus forming a sandstorm with a range of thousands of kilometers. This climate phenomenon can last for months at a time. When it reaches this scale, at first glance, sandstorms can almost cover Mars.

This photo captures the sandstorm activity on Mars.

Due to the thin air, low temperature and lack of magnetosphere, there will be no liquid precipitation such as rainfall on Mars. Generally speaking, solar radiation will decompose all moisture in the atmosphere into hydrogen and oxygen. Due to the cold and thin atmosphere, there is not enough liquid water on the surface to maintain the water cycle.

However, sometimes thin clouds form in the atmosphere and fall back to the ground in the form of snow. The main component is "dry ice snowflake", and traces of this substance have been found in the polar regions. In any case, some traces of water-containing frozen clouds have been found in the upper atmosphere of Mars before, but the snowfall is only in high latitudes.

This phenomenon was observed on 29 September 2008. At that time, four kilometers (2.5 miles) above the landing site near Heimdahl crater, snowflakes were scattered from the clouds, and the Phoenix Mars lander recorded this moment in the form of photos. However, the data collected by the recorder shows that the snowfall has evaporated before reaching the ground.

Mars aurora:

Mars also has aurora phenomenon, which is also the result of the interaction between Martian magnetic field and solar radiation. Although there are few magnetospheres on Mars to discuss, scientists have concluded that the aurora monitored in the past corresponds to a region-the region with the strongest local magnetic field on the earth. This conclusion is obtained by analyzing the data surveyed by Mars Global Prospector and editing the magnetic anomaly map of the crust.

There are magnetized rocks on the crust of Mars, which in turn produce a local and incomplete magnetic field (left). In the picture on the right, we can see those areas extending into the space above the rocks. Above them, auroras form.

The aurora phenomenon that occurred on August 14, 2004 is a famous example, which was identified by the Mars atmospheric spectral characteristic measurer on the Mars Express spacecraft. The location of this aurora phenomenon is located in the Similia Plateau on Mars-geographical coordinates: east longitude 177, south latitude 52; Moreover, its prediction range is considerable, with the measured data being 30km horizontally and 8km vertically (i.e. horizontal 18.5 miles and vertical 5 miles).

Recently, another aurora phenomenon has been observed. It is only one day away from the aurora phenomenon found on the earth. The observation equipment is a detector to detect the evolution of Martian atmosphere and volatiles. It once took an aurora image of 17 in March of 20 15. This aurora is nicknamed "Christmas Light of Mars" and runs through the north latitude of Mars. And compared with the vibrant aurora on earth, it is like a dim candlelight (due to the lack of oxygen and nitrogen in the atmosphere of Mars).