Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It only takes a minute to sign up.
Sign up to join this community
I know in these regions sunlight barely falls & sometimes it won't fall at all.
If sunlight doesn't fall for a very long time it doesn't mean that the whole region should become very cold.
For example: a hot cup after some time becomes cold because of heat exchange with the surroundings.
Earth having normal temperature, even heat exchange happens surface would be cold not very cold with glaciers,mountains etc.
What is cooling the north & south poles?
"then who is cooling the north-south poles?"
This is the wrong question, it should read who or what is heating up the rest. If there were no sources of heat in the Universe, the temperature would be minus 273°C or Absolute $0$! Anywhere that is not getting infra red radiation would tend to this temperature i.e. planets that only show one side to the Sun.
If you measure the amount of infra red radiation falling of a square metre of the Arctic you would find that it is considerably less than that falling on a square metre between the Tropics. Add to this, the fact that both Arctic and Antarctic, due to being white, are reflecting a large part of this energy back into Space.
Absorbing heat radiation is very important, especially for Polar Bears, which despite appearing white actually have dark skin and fur that is black. The fur that we can see only appears white, it is in fact transparent to allow absorption of heat radiation.
