How cold is mars
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How Cold is Mars?
Average Martian Temperatures
Mars is an extremely cold planet with an average temperature of around -63°C, and winter lows can plummet to -120°C. These frigid conditions are a result of Mars' thin atmosphere, which is less effective at retaining heat compared to Earth's thicker atmosphere.
Polar Temperatures and Ice Sheets
The mean annual surface temperatures at the Martian south pole are even colder, averaging around -100°C. During the Noachian-Hesperian boundary, basal melting of ice sheets at the south pole would have required mean annual temperatures to rise to between -50°C and -75°C, which is still significantly below the melting point of water. This suggests that Mars has been predominantly cold and dry for much of its history.
Mesospheric Temperatures
In the upper atmosphere of Mars, temperatures can be as low as 120 K (approximately -153°C) at altitudes between 50 and 80 km. These temperatures are close to the vapor saturation point for CO2, indicating the presence of CO2 ice clouds in the Martian mesosphere.
Early Mars Climate
The early climate of Mars, particularly during the Noachian period, was also characterized by cold conditions. Mean annual air temperatures were well below 0°C, similar to the hyperarid and hypothermal conditions found in Earth's Antarctic McMurdo Dry Valleys. Despite these cold conditions, there were periods of seasonal and daily peak temperatures above 0°C, which could have allowed for transient liquid water activity.
Stability of Liquid Water
Although Mars has been cold with mean global temperatures well below the freezing point of pure water, certain conditions could allow for the presence of liquid water. The presence of solutes in Martian fluids can depress the melting point of water, enabling liquid water to exist at temperatures well below 0°C. This could explain the formation of water-related mineralogies and landscape features on Mars.
Martian Meteorites and Surface Temperatures
Thermochronology studies of Martian meteorites suggest that near-surface temperatures on Mars have not been significantly higher than the present cold state for most of the past 4 billion years. This further supports the notion of a persistently cold Martian climate.
Conclusion
Mars is an exceptionally cold planet with average temperatures far below the freezing point of water. The polar regions are particularly frigid, and even the early climate of Mars was characterized by cold and icy conditions. Despite these harsh temperatures, certain conditions could allow for transient liquid water, contributing to the planet's intriguing geological features.
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