3.7 Heat sources on earth

– fires; internal heat dissipation; volcanoes; creation of electrical energy – coal, nuclear, gas; transport fuel burning; even our bodies converting food to heat. Urban “island” heating.


Geologists have used temperature measurements from more than 20,000 boreholes around the world to estimate that some 44 terawatts (44 trillion watts) of heat continually flow from Earth’s interior into space.

Have seen  a photo of a ring of volcanoes spewing heat right around the Antarctic ?continent. Cannot find where I stored it, if i did.

Uh, oh. New study shows Earth’s internal heat drives rapid ice flow and subglacial melting in Greenland

Effects of Subsea Volcanic Heat at ‘Digging in Clay’




The average human (according to my Coke® can’s Nutrition Facts label) consumes approximately 2000 Calories per day (it’s actually usually somewhere between 2200 and 4000, but 2000 is a nice number). Using a simple conversion (1000 calories = 1 Calorie, 1 calorie = 4.1868 J), this amounts to 8.37 x 106 joules ingested per day.

Human energy equivalentThis means that the average person expends ~8.37 x 106 joules of energy per day, since most of us are in some sort of equilibrium with our surroundings. Assuming most of this energy leaves us in the form of heat, I calculate that on average we radiate ~350,000 J of energy per hour. Since Watt is just Joules per second, this is roughly equal to energy given off by a 100 Watt light bulb!


Heat and Convection in the Earth


”  We will see that in the Earth, convective transfer occurs.

Radiative heat transport (e.g. heating like an electric bar fire) may play a minor role deep in Earth where T > 2000 K. But minerals are probable too opaque for this to me very significant.

Two important questions:-

���� (1) How does heat-flow from Earth compare with other energy sources?

���� (2) Where does Earth’s heat energy come from?

etc  ”


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