Exploring the Earth's Thermal Output: Comparing to Other Interstellar Cores

[dirtyd33]

Is the thermal output, or rather electromagnetic output, of the Earth's core relatively constant? and if so, how does it compare to the output of other interstellar cores, say like mercury or the sun?

 

[Matterwave]

Which one are you asking? Thermal output or electromagnetic (i.e. radiative) output?

For cores, this is very different. The thermal energy of the core would be dissipated by conduction and convection as well as radiation...The radiative aspect of this transport is actually not efficient since the Earth is opaque.

 

[dirtyd33]

The thermal energy of the core would be dissipated by conduction and convection as well as radiation...

My answer to you is yes. I meant the total thermal output of the earth, from the core outward. I want to know if it is fairly constant/ continuous and what might it's capacity be. But now I think of it I'd like to know just the radiative aspect separately, as well.

 

[sylas]

My answer to you is yes. I meant the total thermal output of the earth, from the core outward. I want to know if it is fairly constant/ continuous and what might it's capacity be. But now I think of it I'd like to know just the radiative aspect separately, as well.

The total rate of thermal energy coming up from below the Earth's surface is about 44 TeraWatts.

• Pollack, H.N.; S. J. Hurter, and J. R. Johnson (1993), http://www.agu.org/pubs/crossref/1993/93RG01249.shtml, Rev. Geophys. 30 (3): 267–280

This is a heat flow mainly by conduction and convection; radiation has essentially no role below the surface.

This energy flux has only a negligible contribution to the much larger heat fluxes above the surface, which are dominated by radiation from the Sun.

The geothermal heat flux from the core works out to be a bit under 0.09 W/m², which is negligible by comparison with the energy absorbed from the Sun, which works out to be a bit over 160 W/m².

The energy absorbed at the surface then flows up through the atmosphere and eventually out into space. The outward energy flows are about 17 W/m² by convection, 80 W/m² by latent heat of evaporation, and about 63 W/m² by radiation (radiation here being the difference between thermal radiation upwards and thermal backradiation from the atmosphere). The geothermal flux is several orders of magnitude less than the energy flows above the surface.

Cheers -- sylas

 

[sardar]

The Earth's thermal output, or the amount of heat energy generated by its core, is not constant and can vary over time. This is due to various factors such as the Earth's internal processes and external influences like solar activity.

In comparison to other interstellar cores, the Earth's thermal output is relatively low. The Sun, for example, has a much higher thermal output due to its size and the intense nuclear fusion reactions happening within its core. Mercury, being a smaller planet, also has a lower thermal output than the Earth.

However, it is important to note that the Earth's thermal output is still significant and plays a crucial role in maintaining the planet's habitable conditions. The heat generated by the Earth's core drives plate tectonics, which helps regulate the planet's temperature and provides nutrients for life to thrive.

Overall, while the Earth's thermal output may be lower compared to other interstellar cores, it is still a crucial factor in the planet's overall functioning and ability to support life.