-
Vesto Slipher measured redshift in the spectrum of the Andromeda galaxy (then called the Andromeda Nebula), indicating it was moving away.
➤ First evidence suggesting the universe was not static. -
Alexander Friedmann published a solution to Einstein’s general relativity equations, showing an expanding universe was possible.
➤ First theoretical model of an expanding cosmos -
Edwin Hubble presented findings that Andromeda is a separate galaxy, based on Cepheid variable stars.
➤ Proved the universe is much bigger than the Milky Way -
Georges Lemaître published his paper in Annales de la Société Scientifique de Bruxelles, proposing the universe began from a "primeval atom."
➤ Birth of the Big Bang Theory concept. -
Edwin Hubble published a paper showing that galaxies are moving away from us in proportion to their distance, now known as Hubble’s Law.
➤ Confirmed the universe is expanding. -
Fritz Zwicky analyzed the Coma Cluster and noticed that its mass didn't match its brightness, inferring the existence of unseen "dark matter."
➤ First evidence for dark matter -
Arno Penzias and Robert Wilson detected strange background noise at Bell Labs — the leftover heat from the early universe.
➤ Strong proof for the Big Bang -
NASA ESA placed Hubble in Earth orbit by the Space Shuttle Discovery (STS-31 mission).
➤ Revolutionized our view of deep space and helped refine the age of the universe. -
NASA COBE (Cosmic Background Explorer) Team
announced detailed measurements of temperature fluctuations in the CMB.
➤ Supported how galaxies and structures formed in the early universe -
Saul Perlmutter, Brian Schmidt, Adam Riess (the Nobel prize-winning Supernova Team)
discovered that distant supernovae were dimmer than expected — the universe’s expansion is accelerating.
➤ Introduced dark energy to cosmology.