How do planets lose their heat?

Question

Besides through thermal radiation, how do planets lose their heat?
From what i generally understand, an object gets cooler by getting another object hotter. But if a planet is surrounded by space(which is obviously nothing), then how does it cool down?

Answer 1

Mostly by infrared radiation, which is the lower spectrum of electromagnetic radiations.
http://en.wikipedia.org/wiki/Infrared_radiation

Answer 2

Hi. The core of some planets like the Earth have radioactive material which generates heat miles below the surface. This heat gets transported closer to the surface through convection. The solid layer transports heat through conduction. At the surface heat radiates as Answerer 1 said.

Answer 3

Planets loose heat ONLY by thermal radiation. There is no conduction or convection possible in the vacuum of space.

Answer 4

When their components run out. For example the Sun is made out of helium and hydrogen so it will run out in 5 billion years and it will explode causing a black hole to be created which suckes other planets including the Earth.

Answer 5

There lots of possibilities like: it's atmosphere disappears. cataclysm causes ( an asteroid ) a cloud of dust to blot of the sun. Or the core stops and heat inside stops