Why is the skin of Penguin white and have a thick layer of fat underneath?

Dear student, Penguins have black feathers that help them to absorb radiation from the sun,but this may also cause a little loss of heat from their body.In order to compensate for this,they also have white feathers that preserve heat and help them in camouflage.There furs are designed in such a way that it traps the air to act as insulators.Also , they have fat layer of skin underneath which helps them in staying warm in cold climates. Thanks and regards