How does Antarctica stay frozen? Antarctica receives heat from the Sun every day, so how does it stay frozen?

I have some thoughts about the answer but I'm unsure of whether it is correct; I hope people here can clarify. 

My idea: the heat that Antarctica receives from the Sun is always 'travelling' from one spot to another, but the heat does not stay in a spot long enough to melt the ice.

Please correct me if I'm wrong, thanks.
It doesn't stay frozen.  Ice evaporates (or sublimates is the correct term) under direct sunlight, but that's at a molecular level, it doesn't melt, it goes from solid to gas under sunlight and in the cold, some of this newly formed water vapor goes back being to ice.

In an absolutely dry climate, well below freezing, ice would slowly sublimate and disappear.  In a warm dry climate, ice would melt (much faster), then it would evaporate.   The sun does sublimate ice off the antarctic ice sheet every day, but quite a bit less than is added by snow and condensation from moisture due to temperature change and brought over by wind.   The antarctic ice sheet is also, always moving.   Mostly Antarctica loses ice by pushing it into the ocean - over long periods of time and it gains ice by (see above) snow and condensation.   The ice has been on Antarctica for over 30 million years, but as far as I know, the oldest ice core we've found there is about 1.5 million years old.    Everything moves.