To Early!

Why is light so bright? That is a stupid question to ask. However, in the morning when you have been up until 4am the night before and want to get some sleep the sun going through the blinds around 10am is horrible! As I am waking up though I thought about how can I solve this issue. It dawned on me to hang thick heavy black sheets over the windows to "block the light." Now I am thinking why and how the sunlight is being blocked by the sheets. The black sheets are absorbing the sunlight completely and allowing it to be captured in the sheets itself instead of passing through to the rest of the room. The only problem was that the sheets would get hot from the sunlight however in the end it did its purpose and let me sleep!