HELL BACK
TO AND
THE NATURAL GENIUS OF GEOTHERMAL ENERGY
BY BILL MUHLENFELD 54
Sustain
DEPARTMENT
INNER CORE
OUTER CORE MANTLE
CRUST
Earth's greatest source of heat, besides the sun, is its interior, which conducts a hundred billion billion (no misprint!) calories of energy to the surface each year. So much energy radiates from inside the Earth that it could satisfy all human energy needs three times over.
DISTINCTLY MONTANA • AUTUMN 2011
800 MILES
1,400 MILES
1,800 MILES 5 – 25 MILES
