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The Earth can only "gain" heat through #3, solar radiation. The other 3 items you list can store and release heat at a later time, but they can not generate mor
by Afforess 11y ago
The Earth can only "gain" heat through #3, solar radiation. The other 3 items you list can store and release heat at a later time, but they can not generate more heat than they already possess now. (This is not strictly true, conversion of mass to energy, e=mc^2, means that nuclear and fusion energy could create new heat at the expense of matter, but we generally assume that on planets, this is negligible.)
So if people talk about "El Nino" increasing the temperature for the year, this is only possible because previous "La Nina" cycles decreased the temperature by an equivalent amount in previous years, and the oceans are returning the heat to the atmosphere.
Geothermal energy was stored back during the formation of the planet and there is generally just enough to keep the planet a few degrees above absolute zero. The energy released is highly variable though, volcanoes can release lots on one particular day, but then diminished activity for years follows.
- flubert 11y ago>Geothermal energy was stored back during the formation of the planet "Nuclear Fission Confirmed as Source of More than Half of Earth's Heat" http://blogs.scientificamerican.com/observations/nuclear-fission-confirmed-as-source-of-more-than-half-of-earths-heat/ http://blogs.scientificamerican.com/observations/nuclear-fis...
- JBReefer 11y agoThat's talking about radioactive decay, not fission. The article doesn't do a great job distinguishing between the two, but it's _not_ talking about the process of splitting atoms. >The new measurements suggest radioactive decay provides more than half of Earth's total heat, estimated at roughly 44 terawatts based on temperatures found at the bottom of deep boreholes into the planet's crust.
- kaybe 11y agoAFAIK nuclear fission also includes radioactive decay, which does split atoms, or at least part of atoms. https://en.wikipedia.org/wiki/Nuclear_fission https://en.wikipedia.org/wiki/Nuclear_fission
- dTal 11y agoNot only is this pedantic in the context of whether Earth's geothermal energy is "stored" or "generated", it's also wrong. Fission is when an atom breaks into smaller pieces. What is it that you think happens in radioactive decay? From Wikipedia, first line in the article: "...nuclear fission is either a nuclear reaction or a radioactive decay process in which the nucleus of an atom splits into smaller parts (lighter nuclei)." Why would you assume that Scientific American got such an elementary thing wrong, then post it as an argument without even checking?
- Retric 11y agoFission is effectively catalyzed radioactive decay from neutrons at the right energy levels. There could be some differences in decay products, but simply waiting will eventually release that energy. http://www.mpoweruk.com/nuclear_theory.htm http://www.mpoweruk.com/nuclear_theory.htm
- vacri 11y agoEarth can only gain energy through stuff coming from space (solar radiation), but it can gain heat by converting energy stored in other forms.
- JupiterMoon 11y agoThe Earth's heat budget over geological time is 50% radiogenic..
- ergothus 11y agoThat's why I specified "surface".