<P> Internal heat is the heat source from the interior of celestial objects , such as stars , brown dwarfs , planets , moons , dwarf planets , and ( in the early history of the Solar System ) even asteroids such as Vesta , resulting from contraction caused by gravity ( the Kelvin -- Helmholtz mechanism ) , nuclear fusion , tidal heating , core solidification ( heat of fusion released as molten core material solidifies ) , and radioactive decay . The amount of internal heating depends on mass ; the more massive the object , the more internal heat it has ; also , for a given density , the more massive the object , the greater the ratio of mass to surface area , and thus the greater the retention of internal heat . The internal heating keeps celestial objects warm and active . </P>
<P> Internal heat is the heat source from the interior of celestial objects , such as stars , brown dwarfs , planets , moons , dwarf planets , and ( in the early history of the Solar System ) even asteroids such as Vesta , resulting from contraction caused by gravity ( the Kelvin -- Helmholtz mechanism ) , nuclear fusion , tidal heating , core solidification ( heat of fusion released as molten core material solidifies ) , and radioactive decay . The amount of internal heating depends on mass ; the more massive the object , the more internal heat it has ; also , for a given density , the more massive the object , the greater the ratio of mass to surface area , and thus the greater the retention of internal heat . The internal heating keeps celestial objects warm and active . </P>
why do small planets lose internal heat faster than large planets
why do small planets lose internal heat faster than large planets
the more massive the object , the more internal heat it has
the more massive the object , the more internal heat it has