Edwin Hubble

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This article is about the astronomer. For the politician, see Edwin N. Hubbell. For the jazz trombonist, see Eddie Hubble.
Edwin Powell Hubble
Born (1889-11-20)November 20, 1889
Marshfield, Missouri, U.S.A.
Died September 28, 1953(1953-09-28) (aged 63)
San Marino, California, U.S.A.
Residence United States
Nationality American
Fields Astronomy
Institutions University of Chicago
Mount Wilson Observatory
Alma mater University of Chicago
University of Oxford
Known for Hubble sequence
Influenced Allan Sandage
Notable awards Bruce Medal 1938
Franklin Medal 1939
Gold Medal of the Royal Astronomical Society 1940
Legion of Merit 1946
Signature

Edwin Powell Hubble (November 20, 1889 – September 28, 1953)[1] 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.[2] 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[3] 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.[4] American astronomer Vesto Slipher provided the first evidence to this argument almost a decade before.[5][6]

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.[7][8] He tended to believe the frequency of light could, by some so far unknown means, decrease the longer light travels through space.[9]

Biography

Edwin Hubble was born to Virginia Lee James and John Powell Hubble, an insurance executive, in Marshfield, Missouri, and moved to Wheaton, Illinois, in 1900.[10] In his younger days, he was noted more for his athletic prowess than his intellectual abilities, although he did earn good grades in every subject except for spelling. Edwin was a gifted athlete playing baseball, football, basketball, and he ran track in both high school and college.[11] He played a variety of positions on the basketball court from center to shooting guard. In fact Hubble even led the University of Chicago ’s basketball team to their first conference title in 1907.[11] He won seven first places and a third place in a single high school track and field meet in 1906. That year he also set the state high school record for the high jump in Illinois. Another of his personal interests was dry-fly fishing, and he practiced amateur boxing as well.[12]

His studies at the University of Chicago were concentrated on mathematics, astronomy and philosophy, which led to a bachelor of science degree in 1910. Hubble also became a member of the Kappa Sigma Fraternity (and in 1948 was named the Kappa Sigma "Man of the Year"). He spent the three years at The Queen's College, Oxford after earning his bachelors as one of the university's first Rhodes Scholars, initially studying jurisprudence instead of science (as a promise to his dying father),[13] and later added literature and Spanish,[13] and earning his master's degree.[14]

In 1909, Hubble's father moved his family from Chicago to Shelbyville, Kentucky, so that the family could live in a small town, ultimately settling in nearby Louisville. His father died in the winter of 1913, while Edwin was still in England, and in the summer of 1913, Edwin returned to care for his mother, two sisters, and younger brother, as did his brother William. The family moved once more to Everett Avenue, in Louisville's Highlands neighborhood, to accommodate Edwin and William.[15]

Hubble was also a dutiful son, who despite his intense interest in astronomy since boyhood, surrendered to his father’s request to study law, first at the University of Chicago and later at Oxford, though he managed to take a few math and science courses. After the death of his father in 1913, Edwin returned to the Midwest from Oxford, but did not have the motivation to practice law. So he taught Spanish, physics, and mathematics at the New Albany High School in New Albany, Indiana for a year before he resolved to start over, at the age of 25, to become a professional astronomer. He also coached the boys' basketball team there. After a year of high-school teaching, he entered graduate school with the help of his former professor from the University of Chicago to study astronomy at the Yerkes Observatory of the University, where he received his PhD in 1917. His dissertation was titled Photographic Investigations of Faint Nebulae.

When Congress declared war on Germany in 1917, Hubble rushed his dissertation for his PhD, volunteering for the United States Army and was assigned to the newly created 86th Division. He rose to the rank of Major and was found fit for overseas duty on July 9, 1918. The 86th Division never saw combat, and after the end of World War One Hubble spent a year in Cambridge, where he renewed his studies of Astronomy.[16] In 1919, Hubble was offered a staff position in California by George Ellery Hale, the founder and director of the Carnegie Institution's Mount Wilson Observatory, near Pasadena, California, where he remained on the staff until his death. Hubble also served in the U.S. Army at the Aberdeen Proving Ground during World War II. For his work there, he received the Legion of Merit award. Shortly before his death, Mount Palomar's giant 200-inch (5.1 m) reflector Hale Telescope was completed, and Hubble was the first astronomer to use it. Hubble continued his research at the Mount Wilson and Mount Palomar Observatories, where he remained active until his death.

Although Hubble was raised as a Christian, he later became an agnostic.[17][18]

Hubble experienced a heart attack in July 1949 while on vacation in Colorado. He was taken care of by his wife, Grace Hubble, and continued on a modified diet and work schedule. He died of cerebral thrombosis (a spontaneous blood clot in his brain) on September 28, 1953, in San Marino, California. No funeral was held for him, and his wife never revealed his burial site.[19][20][21]

Discoveries

The universe goes beyond the Milky Way galaxy

Edwin Hubble's arrival at Mount Wilson, California in 1919 coincided roughly with the completion of the 100-inch (2.5 m) Hooker Telescope, then the world's largest telescope. At that time, the prevailing view of the cosmos was that the universe consisted entirely of the Milky Way Galaxy. Using the Hooker Telescope at Mt. Wilson, Hubble identified Cepheid variables (a kind of star; see also standard candle) in several spiral nebulae, including the Andromeda Nebula and Triangulum. His observations, made in 1922–1923, proved conclusively that these nebulae were much too distant to be part of the Milky Way and were, in fact, entire galaxies outside our own. This idea had been opposed by many in the astronomy establishment of the time, in particular by the Harvard University-based Harlow Shapley. Despite the opposition, Hubble, then a thirty-five-year-old scientist, had his findings first published in The New York Times on November 23, 1924,[22] and then more formally presented in the form of a paper at the January 1, 1925 meeting of the American Astronomical Society.[23] Hubble's findings fundamentally changed the scientific view of the universe. Supporters of Hubble’s expanding universe theory state that Hubble’s discovery of nebulas outside of our galaxy helped pave the way for future astronomers.[24] Although some of his more renowned colleagues simply scoffed at Hubble's idea of an expanding universe, Hubble ended up publishing his findings on nebulas. This published work earned him an award titled the American Association Prize and five hundred dollars from Burton E. Livingston of the Committee on Awards.[11]

Hubble also devised the most commonly used system for classifying galaxies, grouping them according to their appearance in photographic images. He arranged the different groups of galaxies in what became known as the Hubble sequence.[25]

Redshift increases with distance

The 100-inch (2.5 m) Hooker telescope at Mount Wilson Observatory that Hubble used to measure galaxy distances and a value for the rate of expansion of the universe.

Combining his own measurements of galaxy distances based on Henrietta Swan Leavitt's period-luminosity relationship for Cepheids with Vesto Slipher and Milton L. Humason's measurements of the redshifts associated with the galaxies, he discovered a rough proportionality of the objects' distances with their red shifts.[2] Though there was considerable scatter (now known to be due to peculiar velocities), he was able to plot a trend line from the 46 galaxies and obtained a value for the Hubble Constant of 500 km/s/Mpc, which is much higher than the currently accepted value due to errors in their distance calibrations. In 1929 Hubble formulated the Redshift Distance Law, nowadays termed simply Hubble's law, which, if the redshift is understood to be a measure of recession velocity, is consistent with the solutions of Einstein’s equations of general relativity for a homogeneous, isotropic expanding space. Although concepts underlying an expanding universe were well understood earlier, this statement by Hubble and Humason led to wider-scale acceptance for this view. The law states that the greater the distance between any two galaxies, the greater their relative speed of separation. But two years before, in 1927, Georges Lemaître, a Belgian Catholic priest and physicist, published a paper in an obscure Belgian journal, Annales de la Société Scientifique de Bruxelles. In that paper, he showed that the data collected by Hubble and two other astronomers up to that time was enough to derive a linear velocity-distance relation between the galaxies, and that this supported a model of an expanding universe based on Einstein’s equations for General Relativity.

This discovery was the first observational support for the Big Bang theory which had been proposed by Georges Lemaître in 1927. The observed velocities of distant galaxies, taken together with the cosmological principle, appeared to show that the universe was expanding in a manner consistent with the Friedmann-Lemaître model of general relativity. In 1931 Hubble wrote a letter to the Dutch cosmologist Willem de Sitter expressing his opinion on the theoretical interpretation of the redshift-distance relation:[26]

Mr. Humason and I are both deeply sensible of your gracious appreciation of the papers on velocities and distances of nebulae. We use the term ‘apparent’ velocities to emphasize the empirical features of the correlation. The interpretation, we feel, should be left to you and the very few others who are competent to discuss the matter with authority.

Today, the "apparent velocities" in question are understood as an increase in proper distance that occurs due to the expansion of space. Light traveling through stretching space will experience a Hubble-type redshift, a mechanism different from the Doppler effect (although the two mechanisms become equivalent descriptions related by a coordinate transformation for nearby galaxies).

In the 1930s, Hubble was involved in determining the distribution of galaxies and spatial curvature. These data seemed to indicate that the universe was flat and homogeneous, but there was a deviation from flatness at large redshifts. According to Allan Sandage,

Hubble believed that his count data gave a more reasonable result concerning spatial curvature if the redshift correction was made assuming no recession. To the very end of his writings he maintained this position, favouring (or at the very least keeping open) the model where no true expansion exists, and therefore that the redshift "represents a hitherto unrecognized principle of nature."[27]

There were methodological problems with Hubble's survey technique that showed a deviation from flatness at large redshifts. In particular, the technique did not account for changes in luminosity of galaxies due to galaxy evolution. Earlier, in 1917, Albert Einstein had found that his newly developed theory of general relativity indicated that the universe must be either expanding or contracting. Unable to believe what his own equations were telling him, Einstein introduced a cosmological constant (a "fudge factor") to the equations to avoid this "problem". When Einstein learned of Hubble's redshifts, he immediately realized that the expansion predicted by General Relativity must be real, and in later life he said that changing his equations was "the biggest blunder of [his] life." In fact, Einstein apparently once visited Hubble and tried to convince him that the universe was expanding.[28]

Other discoveries

Hubble discovered the asteroid 1373 Cincinnati on August 30, 1935. He also wrote The Observational Approach to Cosmology and The Realm of the Nebulae approximately during this time.[29]

No Nobel Prize

Hubble spent much of the later part of his career attempting to have astronomy considered an area of physics, instead of being its own science. He did this largely so that astronomers—including himself—could be recognized by the Nobel Prize Committee for their valuable contributions to astrophysics. This campaign was unsuccessful in Hubble's lifetime, but shortly after his death, the Nobel Prize Committee decided that astronomical work would be eligible for the physics prize.[11] However, the prize is not one that can be awarded posthumously.

Stamp

On March 6, 2008, the United States Postal Service released a 41-cent stamp honoring Hubble on a sheet titled "American Scientists" designed by artist Victor Stabin.[20] His citation reads:
Often called a "pioneer of the distant stars," astronomer Edwin Hubble (1889–1953) played a pivotal role in deciphering the vast and complex nature of the universe. His meticulous studies of spiral nebulae proved the existence of galaxies other than our own Milky Way. Had he not died suddenly in 1953, Hubble would have won that year's Nobel Prize in Physics.
The other scientists on the "American Scientists" sheet include Gerty Cori, biochemist; Linus Pauling, chemist, and John Bardeen, physicist.

Honors

Awards

Named after him

In Popular Culture

The play "Creation's Birthday", written by Cornell physicist Hasan Padamsee, tells Hubble's life story.[30]

See also

References and notes

  1. ↑ "Biography of Edwin Powell Hubble (1889–1953)". NASA. Retrieved June 21, 2011. 
  2. ↑ 2.0 2.1 Hubble, Edwin (1929). "A relation between distance and radial velocity among extra-galactic nebulae". PNAS 15 (3): 168–173. Bibcode:1929PNAS...15..168H. doi:10.1073/pnas.15.3.168. PMC 522427. PMID 16577160. 
  3. ↑ Nature. "Edwin Hubble in translation trouble : Nature News". Nature.com. Retrieved 2012-08-15. 
  4. ↑ Hubble, Edwin (12/1926). "Extragalactic nebulae.". Astrophysical Journal (64): 321–369. Bibcode:1926ApJ....64..321H. doi:10.1086/143018. 
  5. ↑ Slipher, V.M. (1917). Proc. Am. Philos. Soc. 56. pp. 404–409. 
  6. ↑ Segal, I.E. (December 1993). Proc. Natl. Acad. Sci. USA 90,. pp. 11114–11116. 
  7. ↑ Effects of Red Shifts on the Distribution of Nebulae, Hubble, Edwin, Astrophysical Journal, vol. 84, p.517, The SAO/NASA Astrophysics Data System
  8. ↑ Red-shifts and the distribution of nebul&aelig, Hubble, Edwin, Monthly Notices of the Royal Astronomical Society, Vol. 97, p.513, The SAO/NASA Astrophysics Data System
  9. ↑ Engelbert Broda: "Weiten des Weltalls: Unsere Milchstraße und ihre Nachbarn" [Ranges of the universe: our Milky Way and its neighbors]. Die Kräfte des Weltalls [The forces of the universe] (in German) (Die Buchgemeinde authorized ed.). Vienna: Globus Zeitungs- Druck- und Verlagsanstalt, Gesellschaft m. b. H. 1954 [1954]. p. 18. "Es könnte [...] auch sein, dass nach einem — bisher noch nicht aufgefundenen — Gesetz der Physik jeder Lichtstrahl im Laufe langer Zeiträume, also beim Durcheilen weiter Strecken, an Schwingungszahl verliert und aus diesem Grunde allmählich röter wird. Da die Energie eines Lichtstrahls um so kleiner ist, je röter das Licht ist, so würde das gleichzeitig bedeuten, dass das Licht im Lauf von Jahrmillionen Energie verliert. (Die Energie müsste dann freilich in anderer Form wieder auftauchen.) Das Licht, das von den fernsten Nebeln stammt, hätte die meiste Energie verloren, und die Rotverschiebung wäre begründet. Zu dieser Anschauung neigt jener Astronom, der sich um die Messung der Rotverschiebung die größten Verdienste erworben hat — Edwin Hubble." English: "It could also be that, according to a — so far not yet discovered — law of physics, every beam of light over long periods of time, i.e. when it hurries through long stretches, decreases in frequency and therefore, little by little, becomes redder. As the energy of a beam of light is the smaller the redder the light is, this would, at the same time, mean that light, over the course of millions of years, loses energy. (The energy would then, of course, have to reappear in an other form.) The light from the farthest galaxies would have lost the most energy so that the redshift would be explained. The astronomer who has contributed to the measurement of the redshift more than any other scientist — Edwin Hubble — tends to this view." 
  10. ↑ Gale E. Christianson (1996). Edwin Hubble: mariner of the nebulae. University of Chicago Press. pp. 13–18. 
  11. ↑ 11.0 11.1 11.2 11.3 Gale E. Christianson (1996). Edwin Hubble: mariner of the nebulae. University of Chicago Press. 
  12. ↑ World of Physics and The Cloudy Night Book
  13. ↑ 13.0 13.1 Michael D. Lemonick (Mar 29, 1999). "Astronomer Edwin Hubble". The Times. UK. Retrieved May 29, 2011. 
  14. ↑ The Rhodes Trust (Hubble, Edwin – The Queen's College, Illinois (1910)). "Rhodes Scholars: Complete List, 1903–2010". The Rhodes Trust. Retrieved May 29, 2011. 
  15. ↑ John F. Kielkopf. "Edwin Hubble, Family, and Friends in Louisville 1909–1916". 
  16. ↑ Gale E. Christianson (1996). Edwin Hubble: Mariner of the Nebulae. University of Chicago Press. p. 183. ISBN 9780226105215. 
  17. ↑ Gale E. Christianson (1996). Edwin Hubble: Mariner of the Nebulae. University of Chicago Press. p. 183. ISBN 9780226105215. "One morning, while driving north with Grace after the failed eclipse expedition of 1923, he broached Whitehead's idea of a God who might have chosen from a great many possibilities to make a different universe, but He made this one. By contemplating the universe, one might approximate some idea of its Creator. As time passed, however, he seemed even less certain: "We do not know why we are born into the world, but we can try to find out what sort of a world it is — at least in its physical aspects." His life was dedicated to science and the objective world of phenomena. The world of pure values is one which science cannot enter, and science is unconcerned with the transcendent, however compelling a private revelation or individual moment of ecstasy. He pulled no punches when a deeply depressed friend asked him about his belief: "The whole thing is so much bigger than I am, and I can't understand it, so I just trust myself to it; and forget about it."" 
  18. ↑ Tom Bezzi (2000). Hubble Time. iUniverse. p. 93. ISBN 9780595142477. "John terribly depressed, and asked Edwin about his belief. Edwin said, "The whole thing is so much bigger than I am, and I can't understand it, so I just trust myself to it, and forget about it." It was not his nature to speculate. Theories, in his opinion, were appropriate cocktail conversation. He was essentially an observer, and as he said in The Realm (J the Nebulae: “Not until the empirical resources are exhausted, need we pass on to the dreamy realms of speculation.” Edwin never exhausted those empirical resources. “I am an observer, not a theoretical man,” he attested, and a lightly spoken word in a lecture or in a letter showed that observation was his choice." 
  19. ↑ Bill Bryson (2010). Short History of Nearly Everything: Special Illustrated Edition. Random House Digital, Inc. 
  20. ↑ 20.0 20.1 Paul Kupperberg (2005). Hubble and the Big Bang. The Rosen Publishing Group. pp. 45–6. 
  21. ↑ J. L. Heilbron (2005). The Oxford guide to the history of physics and astronomy, Volume 10. Oxford University Press US. pp. 156–7. 
  22. ↑ Sharov, Aleksandr Sergeevich; Novikov, Igor Dmitrievich (1993). Edwin Hubble, the discoverer of the big bang universe. Cambridge University Press. p. 34. ISBN 978-0-521-41617-7. Retrieved December 31, 2011. 
  23. ↑ Marcia Bartusiak (2010). The Day We Found the Universe. Random House Digital, Inc. pp. x–xi. 
  24. ↑ "life in the universe Astronomy Encyclopedia. London: Philip's, 2002. Credo Reference". 
  25. ↑ David L. Block, Ivacircnio Puerari, Alan Stockton (2000). Toward a new millennium in galaxy morphology. Springer. pp. 146–150. 
  26. ↑ Robert P. Kirshner (January 6, 2004). "Hubble’s diagram and cosmic expansion". PNAS. Retrieved February 12, 2012. 
  27. ↑ Sandage, Allan (1989), "Edwin Hubble 1889–1953", The Journal of the Royal Astronomical Society of Canada, Vol. 83, No.6. Retrieved March 26, 2010.
  28. ↑ Public Broadcasting Station (PBS). "Cosmological Constant". PBS.org. Retrieved May 29, 2011. 
  29. ↑ "Edwin Hubble". FamousScientists.org. Retrieved December 15, 2011. 
  30. ↑ Symmetry Magazine, "On Stage: Hubble's Contentious Life and Science"

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