What are the similarities and differences between a black hole and a black body?
There is no connection between these two concepts (except the word black).
Black bodies are theoretical objects that emit radiation with a distribution depending only on the temperature of the body, i.e. not effected by the material of the object.
Black holes are massive astronomical objects, which are so small in volume that gravity prevents anything from escaping.
Black holes do radiate as a perfect blackbody though (Hawking radiation)
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