kiloVolts wrote:
[snip]

since the radius of the Sun R, is almost infinite, the power
density per unit mass is infinitesimal.
[snip rest]

Learn some math. Core power generation is 0.3 W/m^3 within about 10%
of the sun's total volume of 1.412×10^27 m³

(0.3 W/m^3)(0.1)(1.412×10^27 m^3) = 4.24x10^25 watts

That is nowhere near either zero or infinity (even the small one).
Number check: solar constant at 1 AU = 1368 W/m^2

(1368 W/m^2)(4)(pi)[1.496x10^11 m/AU)]^2 = 3.85x10^26 watts

Consistent within a factor of 9. Good enough.

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/lajos.htm#a2