By using Cepheid variable stars to calculate the distance of the Andromeda Nebula (as it was then known) from the Earth, Hubble showed that it was a separate galaxy and not a gas cloud in the Milky Way. Later, by comparing the relative velocities of galaxies (measured as red shifts) with his measurements of their distances from the Earth, Hubble showed that the further away a galaxy is from any point in space, the faster it appears to move because of the expansion of the Universe – Hubble's Law.
Image: Hubble at Palomar Observatory (credit: Emilio Segre Visual Archives/AIP/SPL)
An American astronomer measures the Universe's expansion.
The great astronomer worked at Mount Wilson Observatory.
This clip was filmed at a time when the Hubble Space Telescope had been discovered to have a flawed mirror, hence the reference to "failure". The Hubble Space Telescope went on to become one of the most successful NASA missions. This clip looks at some of the American astronomer Edwin Hubble's most important contributions to astronomy and the equipment he used at the Mount Wilson Observatory. The age of the Universe is now thought to be 13.7 billion years.
Patrick Moore's guest reviews the world's large observatories.
Sir Patrick Moore's guest Professor Richard Ellis from the University of Oxford reviews the world's large observatories and explains their importance. [The black and white images of Edwin Hubble, George Hale, Mount Wilson, the 200-inch telescope and mirror making in this clip are copyright Palomar Observatories/Caltech]
Edwin Hubble discovers galaxies outside the Milky Way.
Edwin Hubble discovers galaxies outside the Milky Way and measures how far away they are.
Edwin Powell Hubble (November 20, 1889 – September 28, 1953) was an American astronomer who played a crucial role in establishing the field of extragalactic astronomy and is generally regarded as one of the most important observational cosmologists of the 20th century. Hubble is known for showing that the recessional velocity of a galaxy increases with its distance from the earth, implying the universe is expanding. Known as "Hubble's law", this relation had been discovered previously by Georges Lemaître, a Belgian priest/astronomer who published his work in a less visible journal. There is still much controversy surrounding the issue and some argue that it should be referred to as "Lemaître's law" although this change has not taken hold in the astronomy community.
Hubble is also known for providing substantial evidence that many formerly known "nebulae" were actually galaxies beyond the Milky Way. American astronomer Vesto Slipher provided the first evidence to this argument almost a decade before.
Hubble supported the Doppler shift interpretation of the observed redshift that had been proposed earlier by Slipher, and that led to the theory of the metric expansion of space. He tended to believe the frequency of light could, by some so far unknown means, decrease the longer light travels through space.