In 1920, astronomers Harlow Shapley and Heber Curtis held a Great Debate. Shapley argued that the spiral nebulae were small ...

The idea that the universe is expanding was first proposed by Edwin Hubble in the late 1920s and ... Lemaître to propose the ...

Even Einstein was reluctant to endorse this extension of his theory of general relativity. In 1929 at the Mt. Wilson Observatory in California, Edwin Hubble discovered that galaxies were moving ...

Edwin Powell Hubble is renowned for determining that ... and confirmation of the big bang theory. Hubble calculated it to be about 2 billion years ago, but more recent estimates have revised ...

It wasn't until 1949 that the term "big bang" came into fashion. This was a relief to Edwin Hubble's contemporary ... He was partly right in that Einstein's theory of special relativity explained ...

Belgian cosmologist and Catholic priest Georges Lemaitre made that connection by realizing that the theory ... the big bang, when the universe was 20 times smaller than it is now. Edwin Hubble ...

The Big Bang Theory explains how the universe began. The Big Bang Theory stands as the most widely accepted explanation for the origin of the universe. According to this theory, the universe began ...

The Andromeda galaxy helped Edwin Hubble settle a great debate in astronomy. Stocktrek Images via Getty Images ...