ishalon

What causes the Earth's magnetic field?
The mantle?

beausoleil

No, the outer core.

<a href="http://www.sciencenews.org/sn_arc99/11_13_99/fob5.htm" target="_blank">http://www.sciencenews.org/sn_arc99/11_13_99/fob5.htm</a>

<a href="http://www.igpp.lanl.gov/Geodynamo.html" target="_blank">http://www.igpp.lanl.gov/Geodynamo.html</a>

(Edited to add links)

[ July 07, 2002: Message edited by: beausoleil ]</p>

ishalon

which reminds me, where does the earth's inner heat come from?

[Edit: thanks]

[ July 07, 2002: Message edited by: ishalon ]</p>

Autonemesis

Decay of radioactive elements primarily, and residual heat from the formation of the earth. Very slight amounts from tidal flexure and other processes with net energy inflows, if you want to get into accounting for all of it down to the last erg.

beausoleil

Most of the Earth's heat comes from radioactive decay of long-lived radioactive elements in the mantle - notably potassium and uranium.

Another significant source is latent heat released as the liquid outer core crystallises onto the solid inner core. When a liquid turns into a solid it releases heat.

From memory I think the relative production is about 10 to 1

It has been suggested that the former drives the mantle convection associated with continental drift, while the latter drives the hot spots responsible for intra-plate volcanoes. (loosely speaking)

ishalon

And where did the universe's heat come from?

Starspun

The devil. Is that what you want to hear?

beausoleil

What do you mean by 'the universe's heat'?

ishalon

Sorry, all the heat in the universe?

beausoleil

Yes, I understand that, I just don't think it's a very well defined concept.

Do you mean 'by what mechanism has heat been generated in the universe?'?. Or do you mean 'where did the energy that will all end up as heat come from?'? Or do you mean something else?