Why does Neptune emit more energy than it receives from the Sun?

Answer 1

Neptune is not the only planet to emit more energy than it receives from the Sun. The real quizzer here is why does it emit SO MUCH more. Previous answers reflect upon the mass-energy relationship to the creation of new stars and I would suggest that though the theory is solid the example does not fit- the mass is way too small for Jupiter or Neptune to ever become stars and the physical process does not resemble this activity in the least.
Plus we are talking about energy emission here and not energy consumption. Energy emission falls into several major categories that are included in the answer for this basic question. The real answer comes from the type of energy being created- magnetic, electrical, kinetic, etc.
One such energy source reflects upon radio energy which many scientists have projected occurs from dissimilar metals in relative close contact to each otther and seperated by chemical "ice' such as sulfuric acid or a strong catalyst of this nature. Neptune may be a large portion of active magma below the surface as well.

Answer 2

When a Sun/Star is born, it has to reach a certain Mass that will produce the Gravitational Pressure to cause Nuclear Fission/Fusion (Get those mixed up, I think it Fission). Then the Mass ignites into a Burning Ball called a Sun.
Jupiter and Neptune have enough mass that they are producing more heat than they Absorb. Planets gain this mass over large periods of time, from Stellar Dust and Asteroids, that stuff. NOW these planets have an amount of mass, but, it has not reached the point they could "Ignite" and become a Star. Guess it be Billions of years for this to happen. This is how I understand this. Maybe someone can explain better.

Answer 3

The energy get frm sun is to bombording with the radio active materials in Neptune.

so Nuclear reaction called exothermic reaction will takes place.
so heat will be emmited.