Busted The Milky Way Is All There is In the early 1900s no one knew supporters had no proof of that how vast the universe really was Then Edwin Hubble made the first But that changed in 1920 That of two key discoveries that busted year American astronomer Harlow Shapley's hypothesis Shapley accurately measured Earth's In 1919 Hubble worked at the galaxy the Milky Way According to Mt Wilson Observatory in California his calculations it was 100 000 The observatory's 100 inch Hooker light years across He and many Telescope was the biggest telescope other astronomers argued that was of its day With it Hubble took it The Milky Way was the universe thousands of photographs of spiral Other astronomers disagreed nebulae over time On October 4 Heber Curtis thought Earth's galaxy 1924 he was comparing photos was one of many But he and his of the Andromeda Nebula He discovered a Cepheid variable A Cepheid is the one kind of star Scientists astronomers use to accurately continue to study measure distance Shapley had used the Milky Way a Cepheid to make his calculations in 1920 Using the Cepheid in Andromeda Hubble discovered it was 900 000 light years away Andromeda was outside our galaxy way outside of it Later astronomers found Hubble's new number was
The Andromeda Galaxy Andromeda was actually more than twice that distance from number is likely to increase too New technologies and research methods may reveal even more Earth But Hubble's discovery still busted Shapley's theory Hubble galaxies also discovered Andromeda itself was a galaxy The Milky Way was not the only galaxy in the universe Now fewer than 100 years later 2 54 million scientists know there are at least 100 billion galaxies out there That Distance in light years from Earth to the Andromeda galaxy THE SHAPLEY CURTIS DEBATE On April 26 1920 astronomers Harlow Shapley and Heber Curtis held a debate in Washington DC They argued about the size of the universe Shapley argued the universe ended at the limits In 1920 Shapley measured the Milky Way to be 100 000 light years wide Four years later Hubble found a star in Andromeda that was nine times farther away than Shapley thought This proved Andromeda was outside Earth's galaxy and the universe was much bigger than previously thought of Earth s galaxy Curtis argued the Milky Way was one of many island universes Astronomers now call this the Great
Busted Space Is Standing still In 1687 Sir Isaac Newton published years scientists firmly believed the first volume of his famous Newton's vision of the universe In the twentieth century Albert work Principia Mathematica In it he outlined his laws of gravity and motion He also described his Einstein calculated that the universe was expanding But he thought he belief that the universe must have made a mistake He is infinite and came up with a mathematical explanation that would unmoving For hundreds of account for the movement Sir Isaac Newton thought the universe was stationary 70 Estimated kilometers per second per megaparsec at which the universe is expanding Until the early twentieth century most scientists thought the universe was stationary Hubble discovered galaxies were actually moving away from Earth and everything else in the universe This meant the universe is expanding
The Hubble constant states that galaxies move at a constant rate He later called this his greatest blunder was not standing still As Einstein's calculations had predicted it was actually expanding This discovery rocked the scientific community In 1929 Edwin Hubble made another astonishing discovery After discovering Andromeda he and his assistant Milton Humason THE BIG BANG THEORY identified and catalogued galaxies They also measured each galaxy's Doppler shift That is the change in the length of light or sound waves The waves change length as the observer and galaxy move If the universe is expanding where did it start Scientists reasoned it must have begun in one place and at one moment in the past In 1949 George Gamow proposed a theory that would explain the origin of the universe He called it the Big Bang Theory The universe started in an explosion from a single tiny point and expanded outward It is still going apart or toward each other Hubble and Humason found all galaxies are moving away from Earth and away from each other They did so at a consistent rate now called the Hubble constant The universe
