SDSS-III. Hubble Digs Deeply, Toward Big Bang. Hubble Digs Deeply, Toward Big Bang How do astronomers know when they have looked too far into space?
Maybe when they have run out of galaxies to view. That hasn't happened yet. There are still far reaches of space that have not been explored by even the most powerful telescopes, innumerable galaxies that have not been seen by human eyes. Voyager - The Interstellar Mission.