Mercury planet temperature
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Mercury Planet Temperature
Dark-Side Temperature of Mercury
The dark side of Mercury, which is perpetually facing away from the Sun, has an average temperature of approximately 111 K. This temperature is derived from observations at various infrared wavelengths and suggests that Mercury's surface has thermal properties similar to those of the Moon .
Sub-Solar Point Temperature
The sub-solar point, or the point on Mercury's surface directly facing the Sun, experiences extreme temperatures. Observations indicate that this region can reach temperatures as high as 1,100 K, significantly higher than the 600-700 K expected from solar radiation alone. This discrepancy is due to the critical dependence on the temperature of the dark hemisphere .
Diurnal Temperature Variations
Mercury undergoes significant temperature variations throughout its diurnal cycle. At the equator, temperatures can range from less than 100 K during the night to up to 700 K at local noon at certain longitudes. This variation is influenced by Mercury's 3:2 spin-orbit resonance, which causes local noon at longitudes 0° W and 180° W to coincide with perihelion, resulting in "hot" poles, while longitudes 90° W and 270° W experience local noon at aphelion, resulting in "warm" poles .
Surface and Subsurface Thermal Properties
Recent observations and models indicate that Mercury's surface and subsurface thermal properties are similar to those of the Moon. The planet's rotation period of 58.65 days and the lack of an atmosphere mean that surface temperatures can be computed without accounting for atmospheric effects. The equatorial midnight temperature is around 100 K, and the time-averaged microwave temperature increases by approximately 25% from millimeter to decimeter wavelengths, suggesting that radiation plays a significant role in heat transport within the subsurface .
Polar Temperatures and Water Ice Stability
Despite Mercury's proximity to the Sun, the temperatures at its poles, particularly in permanently shadowed craters, can be extremely low. Flat, low-reflectivity surfaces at the poles do not exceed 167 K, and temperatures in the largest craters can be as low as 60 K. These conditions are conducive to the stability of water ice, which can remain stable at temperatures below 112 K over billions of years .
Internal Temperature Distribution
The internal temperature distribution of Mercury is influenced by its core and mantle structure. The highest internal temperature, around 1380 K, occurs at the core-mantle boundary on the sunward side. This temperature distribution suggests that neither the core nor the mantle is molten, and the peculiar temperature distribution may have geophysical and astronomical implications due to Mercury's synchronous rotation about the Sun .
Conclusion
Mercury exhibits extreme temperature variations due to its lack of atmosphere and unique rotational dynamics. The dark side remains extremely cold, while the sub-solar point can reach scorching temperatures. The poles, particularly in shadowed craters, can harbor stable water ice due to their low temperatures. Understanding these temperature dynamics is crucial for future missions and studies of Mercury's surface and internal structure.
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