Temperature on planet mercury
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Temperature on Planet Mercury
Overview of Mercury's Temperature Variations
Mercury, the closest planet to the Sun, experiences extreme temperature variations due to its lack of a significant atmosphere and its unique rotational dynamics. The planet's surface temperatures can range dramatically from scorching highs to frigid lows.
Daytime Temperatures on Mercury
Sub-Solar Point Temperatures
At the sub-solar point, where the Sun is directly overhead, temperatures on Mercury can soar to approximately 1,100 K. This is significantly higher than the 600-700 K expected from solar radiation alone, suggesting that the temperature of the dark hemisphere plays a critical role in this estimation1.
Equatorial and Noon Temperatures
During the day, especially at local noon, equatorial temperatures can reach up to 700 K at longitudes 0° W and 180° W, which coincide with perihelion, the closest point to the Sun in Mercury's orbit. At longitudes 90° W and 270° W, which experience local noon at aphelion, temperatures are slightly lower, reaching up to 570 K3. This results in "hot" and "warm" poles around the equator due to Mercury's 3:2 spin-orbit resonance.
Nighttime and Dark-Side Temperatures
Dark-Side and Equatorial Midnight Temperatures
On the dark side of Mercury, temperatures plummet drastically. Observations have shown that the average dark-side temperature is around 111 K2. At equatorial midnight, temperatures can drop to approximately 100 K5. These low temperatures are due to the absence of sunlight and the planet's inability to retain heat.
Polar Regions and Permanently Shadowed Craters
In the polar regions, particularly within permanently shadowed craters, temperatures can be even lower. These areas can maintain temperatures as low as 60 K, which is cold enough to support the stability of water ice over geological timescales6.
Thermal Inertia and Surface Properties
Surface and Subsurface Thermal Properties
The thermal inertia of Mercury's surface, which is similar to that of the Moon, indicates that the planet has a similar top surface layer. This property affects how quickly the surface heats up and cools down2. The subsurface thermal properties, derived from microwave and infrared observations, suggest that radiation plays a significant role in heat transport within Mercury's subsurface5.
Conclusion
Mercury's temperature profile is characterized by extreme variations, with daytime temperatures reaching up to 1,100 K at the sub-solar point and nighttime temperatures dropping to as low as 100 K at the equator and 60 K in polar craters. These variations are influenced by the planet's lack of atmosphere, its rotational dynamics, and its surface and subsurface thermal properties. Understanding these temperature dynamics is crucial for future missions and studies of Mercury's geology and potential for hosting water ice.
Sources and full results
Most relevant research papers on this topic
Mercury: The Dark-Side Temperature
The average dark-side temperature of Mercury is 111 3 K, suggesting similar top surface layers to the moon.
Estimation of surface temperatures on Mercury in preparation of the MERTIS experiment onboard BepiColombo
The surface of Mercury experiences large temperature variations, with temperatures reaching up to 700 K at local noon at the equator and 570 K at longitudes 90° W and 270° W, depending on solar irradiation.
Thermophysics of the planet Mercury
Mercury's thermophysical behavior closely approximates that of the Moon, with radiation playing a significant role in heat transport in the subsurface.
The Thermal Stability of Water Ice at the Poles of Mercury
Water ice may exist at Mercury's poles, where temperatures are expected to be below 112 kelvin, making it stable to evaporation over billions of years.
Highly CitedMercury’s seasonal sodium exosphere: MESSENGER orbital observations
The bulk of Mercury's sodium exosphere is about 1200 K warmer than its surface, with photon-stimulated desorption being the primary ejection process.
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