Portal:Cosmology/Selected scientist

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

Selected scientist 1

Portal:Cosmology/Selected scientist/1

Edwin Powell Hubble (November 20, 1889 – September 28, 1953) was an American astronomer. He played a crucial role in establishing the fields of extragalactic astronomy and observational cosmology and is regarded as one of the most important astronomers of all time.

Hubble discovered that many objects previously thought to be clouds of dust and gas and classified as "nebulae" were actually galaxies beyond the Milky Way. He used the strong direct relationship between a classical Cepheid variable's luminosity and pulsation period (discovered in 1908 by Henrietta Swan Leavitt) for scaling galactic and extragalactic distances.

Hubble provided evidence that the recessional velocity of a galaxy increases with its distance from the earth, a property now known as "Hubble's law", despite the fact that it had been both proposed and demonstrated observationally two years earlier by Georges Lemaître. Hubble's Law implies that the universe is expanding. A decade before, the American astronomer Vesto Slipher had provided the first evidence that the light from many of these nebulae was strongly red-shifted, indicative of high recession velocities.

Selected scientist 2

Portal:Cosmology/Selected scientist/2

Stephen Hawking 2013.png
Stephen William Hawking CH CBE FRS FRSA (8 January 1942 – 14 March 2018) was an English theoretical physicist, cosmologist, and author, who was director of research at the Centre for Theoretical Cosmology at the University of Cambridge at the time of his death. He was the Lucasian Professor of Mathematics at the University of Cambridge between 1979 and 2009.

His scientific works included a collaboration with Roger Penrose on gravitational singularity theorems in the framework of general relativity and the theoretical prediction that black holes emit radiation, often called Hawking radiation. Hawking was the first to set out a theory of cosmology explained by a union of the general theory of relativity and quantum mechanics. He was a vigorous supporter of the many-worlds interpretation of quantum mechanics.

Selected scientist 3

Portal:Cosmology/Selected scientist/3

Georges Henri Joseph Édouard Lemaître, RAS Associate (French: [ʒɔʁʒᵊ ləmɛ:tʁᵊ] (About this sound listen); 17 July 1894 – 20 June 1966) was a Belgian Catholic priest, astronomer and professor of physics at the Catholic University of Leuven. He proposed on theoretical grounds that the universe is expanding, which was observationally confirmed soon afterwards by Edwin Hubble. He was the first to derive what is now known as Hubble's law and made the first estimation of what is now called the Hubble constant, which he published in 1927, two years before Hubble's article. Lemaître also proposed what became known as the "Big Bang theory" of the origin of the universe, which he called his "hypothesis of the primeval atom" or the "Cosmic Egg".

Selected scientist 4

Portal:Cosmology/Selected scientist/4

Albert Einstein 1921 by F Schmutzer.jpg
Albert Einstein (/ˈnstn/; German: [ˈalbɛɐ̯t ˈʔaɪnʃtaɪn] (About this sound listen); 14 March 1879 – 18 April 1955) was a German-born theoretical physicist who developed the theory of relativity, one of the two pillars of modern physics (alongside quantum mechanics). His work is also known for its influence on the philosophy of science. He is best known to the general public for his mass–energy equivalence formula E = mc2, which has been dubbed "the world's most famous equation". He received the 1921 Nobel Prize in Physics "for his services to theoretical physics, and especially for his discovery of the law of the photoelectric effect", a pivotal step in the development of quantum theory.