Thermophysics is the application of

thermodynamics Thermodynamics is a branch of physics that deals with heat, work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quantities is governed by the four laws of the ...

geophysics Geophysics () is a subject of natural science concerned with the physical processes and physical properties of the Earth and its surrounding space environment, and the use of quantitative methods for their analysis. The term ''geophysics'' som ...

and to planetary science more broadly. It may also be used to refer to the field of thermodynamic and transport properties.

Remote sensing

Earth thermophysics is a branch of

that uses the naturally occurring surface temperature as a function of the cyclical variation in solar radiation to characterise planetary material properties. Thermophysical properties are characteristics that control the diurnal, seasonal, or climatic surface and subsurface temperature variations (or thermal curves) of a material. The most important thermophysical property is

thermal inertia In thermodynamics, a material's thermal effusivity, thermal inertia or thermal responsivity is a measure of its ability to exchange thermal energy with its surroundings. It is defined as the square root of the product of the material's thermal co ...

, which controls the amplitude of the thermal curve and

albedo Albedo (; ) is the measure of the diffuse reflection of solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body that refl ...

(or

reflectivity The reflectance of the surface of a material is its effectiveness in Reflection (physics), reflecting radiant energy. It is the fraction of incident electromagnetic power that is reflected at the boundary. Reflectance is a component of the respon ...

), which controls the average temperature. This field of observations and computer modeling was first applied to

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...

due to the ideal atmospheric pressure for characterising granular materials based upon temperature. The

Mariner 6 A sailor, seaman, mariner, or seafarer is a person who works aboard a watercraft as part of its crew, and may work in any one of a number of different fields that are related to the operation and maintenance of a ship. The profession of the s ...

Mariner 7 A sailor, seaman, mariner, or seafarer is a person who works aboard a watercraft as part of its crew, and may work in any one of a number of different fields that are related to the operation and maintenance of a ship. The profession of the s ...

, and

Mariner 9 Mariner 9 (Mariner Mars '71 / Mariner-I) was a robotic spacecraft that contributed greatly to the exploration of Mars and was part of the NASA Mariner program. Mariner 9 was launched toward Mars on May 30, 1971 from LC-36B at Cape Canaveral Air ...

spacecraft carried thermal infrared

radiometer A radiometer or roentgenometer is a device for measuring the radiant flux (power) of electromagnetic radiation. Generally, a radiometer is an infrared radiation detector or an ultraviolet detector. Microwave radiometers operate in the microwave w ...

s, and a global map of thermal inertia was produced from modeled surface temperatures collected by the Infrared Thermal Mapper Instruments (IRTM) on board the

Viking 1 ''Viking 1'' was the first of two spacecraft, along with ''Viking 2'', each consisting of an orbiter and a lander, sent to Mars as part of NASA's Viking program. The lander touched down on Mars on July 20, 1976, the first successful Mars land ...

and 2 Orbiters. The original thermophysical models were based upon the studies of lunar temperature variations. Further development of the models for Mars included surface-atmosphere energy transfer, atmospheric back-radiation, surface emissivity variations, CO₂ frost and blocky surfaces, variability of atmospheric back-radiation, effects of a radiative-convective atmosphere, and single-point temperature observations.

References

* * * * * * * * * * * {{Cite journal , last=Wesselink , first=A.J. , title=Heat conductivity and nature of the lunar surface material , journal= Bull. Astron. Inst. Neth. , volume=10 , pages=351–363 , year=1948 , bibcode=1948BAN....10..351W Geophysics