Estrelas e buracos negros

https://www.independent.co.uk/news/science/star-black-hole-einstein-relativity-proof-light-a8466041.html

Citando:
"Einstein's 100-year-old general theory of relativity predicted that light from stars would be stretched to longer wavelengths by the extreme gravitational field of a black hole, and the star would appear redder, an effect known as gravitational red shift."