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Vesto Slipher becomes first to observe expansion of the universe.
He was asked to look through a refracting telescope to look at Doppler shifts in nebulae. He observed that one of the Nebulae, Andromeda was coming towards us but as he started looking at other nebulae he saw they were moving away from us. This is when he announced the Universe was expanding. -
Georges LeMaitre proposes Big Bang Theory
Lemaitre publishes his theory that the universe started as a single primordial atom which contained all of the matter in the universe. He had no evidence to back this up so his claim was pushed aside and not taken seriously by scientists -
Edwin Hubble discovers Hubble's law and Redshift
Edwin Hubble uses knowledge from Vesto Slipher to announce Redshift. He goes on top of Mt. Wilson in California with a new 100 inch telescope. He uses the telescope to show that the farther away a galaxy is from us the redder its light is, and the redder the light is, the faster that galaxy is moving away from us. This later became known as Hubble's law. -
Fritz Zwicky becomes first astronomer to hypothesize about Dark Matter
He is known as the "Father of Dark Matter" because while working at the Palomar Observatory he was studying a cluster of galaxies when he noted that the visible mass, single galaxies were moving too fast for the cluster to stay together. He said the explanation had to be matter we could not see or dark matter. He presented all of these findings in the Journal of Swiss Physical Society. It took another 3 decades before these claims were excepted -
Arno Penzias and Robert Wilson discover Cosmic Microwave Background Radiation
While using the Holmdel Horn Antenna Arno Penzias and Robert Wilson picked up a weird humming sound that came from all of the sky at all times. This was the discovery of Cosmic Microwave Background radiation. They measured its temperature to be 3.5 K. These microwaves they had picked up had come from the creation of the universe and provided huge evidence for the Big Bang Theory as this proved once and for all that Georges Lemaitre was indeed correct. -
COBE is launched into space in search of radiation in the universe
NASA launched this big satellite into space in search of radiation throughout the universe. The NASA team had successfully mapped primordial hot and cold spots throughout a lot of the Cosmic Background Radiation. -
Hubble Telescope is launched
After many years of planning and building the Hubble Telescope(first known as the Large Telescope) is launched into space. Since this telescope is outside of Earth's atmosphere it is able to take the clearest pictures of space yet and allows it to see deeper into space then any telescope before it.
