Describing the color yellow to someone who is blind sounds like a task that is completely impossible. It would be like describing what the internet is to someone who is a caveman from the pre-historic era. It could perhaps be even more difficult. Or, it could be equivalent to explaining what the third dimensional world looks like to a being in the 2nd dimension.
Explaining something to someone that which he/she cannot perceive is almost certainly impossible. While blind people are not able to see colors, they do happen to have their senses sharpened in other areas such as touch, taste, hear, and smell.