Which quasar is closest to Earth?

The first quasar to be discovered, 3C 273, turned out to be the closest of all. It lies a billion light years away. Its redshift is z = 0.16. This quasar, apparently, is a black hole with a mass of 2.5 billion solar masses, annually absorbing 25 solar masses of matter from the external environment.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.