Naked Science Forum

On the Lighter Side => That CAN'T be true! => Topic started by: JMLCarter on 11/04/2011 18:46:23

Title: ...that the sun generates about as much energy as a compost heap.
Post by: JMLCarter on 11/04/2011 18:46:23
"Peak power production in the Sun has been compared to the volumetric heats generated in an active compost heap"

http://en.wikipedia.org/wiki/Sun (http://en.wikipedia.org/wiki/Sun)
Title: ...that the sun generates about as much energy as a compost heap.
Post by: JP on 12/04/2011 03:34:00
Well I say that peak power production in the sun is like a dinosaur.

Quick, we can add to wikipedia "peak power production in the sun has also been compared to a dinosaur."  It will be true!  We can even add a citation, which that previous factoid doesn't have!  :)

But in all seriousness, the sun is huge, so the energy per unit volume they quote doesn't seem that unreasonable. It's all about surface area to volume ratios, a ratio which scales like the 1/(radius of the sun).  The radius of the sun is huge, which means that a small amount of energy produced per unit volume of the sun leads to an immense amount of power radiated per unit area.  If you plug in the numbers on that wiki article, I think you get on the order of 10 watts/m3 generated in the sun's core, but 50,000 watts/m2 coming out of the sun's surface.  Therefore a peak power of ~200 watts/m3 doesn't seem so out of line...
Title: ...that the sun generates about as much energy as a compost heap.
Post by: JMLCarter on 14/04/2011 22:46:34
Merits of wikipedia are worthy of more careful debate. Plenty of problems with peer review.

I thought this forum was for established facts that are hard to believe - just for fun. I wasn't looking for an explanation.
Title: ...that the sun generates about as much energy as a compost heap.
Post by: spook1456 on 17/04/2011 06:28:44
well it should be correct but only if the compost heap is large enough . i heard that i gram of matter completely converted into energy will give you a blast about the size of one created by a 20 kiloton nuke
Title: ...that the sun generates about as much energy as a compost heap.
Post by: spook1456 on 17/04/2011 06:29:29
that much energy in a 400 kg compost heap could have powered the sun for a year