Edited by Gerald Boerner
Commentary:
Edwin Hubble may not be a household word, but most school children have heard about the Space Telescope named after him. We have probably heard of the need of this device requiring “glasses” of sorts; an error was made in the optics which required a special shuttle mission to correct. And correct it indeed was the result!
While the Hubble Space telescope was designed years after Edwin Hubble’s death in 1953. However, He was well-known for his concept of an expanding universe that resulted from its creation at the “Big Bang”. His futures contributions involved the speed of expansion being related to the color emitted, based upon the “red shift” of the color which became Hubble’s Law. Stephen Hawking observes that Hubble’s "discovery that the Universe is expanding was one of the great intellectual revolutions of the 20th century."
Although he worked on two of the largest telescopes at his time, the Hooker Telescope at Mt. Wilson and the Hale Telescope at Mount Palomar. These scopes both represented the best optics available at the time. But the atmospheric conditions in Southern California hindered the images that could be seen; photographic films and cameras had not yet reached the refinement needed for recording the extremely faint images required. The Hubble Space Telescope solved that atmospheric condition, as can be seen in the image below.
One of Hubble’s most famous images, Pillars of Creation
shows stars forming in the Eagle NebulaFor your convenience we have included a couple of YouTube videos that illustrate Hubble’s concepts. Please take time to see them; they require Adobe Flash, so those using iPads
willmay need to access them from another computer. They have been tested on a iPad and they played OK.So, let’s get on to our exploration of Edwin Hubble… GLB
These Introductory Comments are copyrighted:
Copyright©2010 — Gerald Boerner — All Rights Reserved[ 3742 Words ]
Quotations Related to EDWIN POWELL HUBBLE
“The great spirals… apparently lie outside our stellar system.”
— Edwin Powell Hubble
“The history of astronomy is a history of receding horizons.”
— Edwin Powell Hubble
“Equipped with his five senses, man explores the universe around him and calls the adventure Science.”
— Edwin Powell Hubble
“For my confirmation, I didn’t get a watch and my first pair of long pants, like most Lutheran boys. I got a telescope. My mother thought it would make the best gift.”
— Wernher von Braun
“Evolutionary cosmology formulates theories in which a universe is capable of giving rise to and generating future universes out of itself, within black holes or whatever.”
— Robert Nozick
“We find them smaller and fainter, in constantly increasing numbers, and we know that we are reaching into space, farther and farther, until, with the faintest nebulae that can be detected with the greatest telescopes, we arrive at the frontier of the known universe.”
— Edwin Powell Hubble
“I also think we need to maintain distinctions – the doctrine of creation is different from a scientific cosmology, and we should resist the temptation, which sometimes scientists give in to, to try to assimilate the concepts of theology to the concepts of science.”
— John Polkinghorne
“My present work concerns the problems connected with the theory of elementary particles, the theory of gravitation and cosmology and I shall be glad if I can manage to make some contribution to these important branches of science.”
— Andrei Sakharov
Edwin Hubble — The Man Who Discovered the Cosmos
Edwin Powell Hubble (1889 – 1953) was an American astronomer who profoundly changed our understanding of the universe by demonstrating the existence of galaxies other than our own, the Milky Way. He also discovered that the degree of "Doppler shift" (specifically "redshift") observed in the light spectra from other galaxies increased in proportion to a particular galaxy’s distance from Earth. This relationship became known as Hubble’s law, and helped establish that the universe is expanding. Hubble has sometimes been incorrectly credited with discovering the Doppler shift in the spectra of galaxies, but this had already been observed earlier by Vesto Slipher, whose data Hubble used.
"I knew that even if I were second or third rate, it was astronomy that mattered."
This sentence, written by Edwin Hubble recalling his youth, tells us a lot about this stubborn, ambitious, sometimes even snobbish and arrogant young man. A man who eventually broke the promise made to his father and followed the path dictated by his passion.
As a result of Hubble’s work, our perception of mankind’s place in the Universe has changed forever: humans have once again been set aside from the centre of the Universe. When scientists decided to name the Space Telescope after the founder of modern cosmology the choice could not have been more appropriate.
Biography of Edwin Hubble
His studies at the University of Chicago concentrated on mathematics, astronomy, and philosophy, which led to a bachelor of science 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 after earning his bachelors as one of Oxford University’s first Rhodes Scholars, studying jurisprudence initially, then switching his major to Spanish and earning his master’s degree in that field. Some of his acquired British mannerisms and dress stayed with him all his life, occasionally irritating his American colleagues.
Upon returning to the United States, Hubble taught Spanish, physics, and mathematics at the New Albany High School in New Albany, Indiana. He also coached the boys’ basketball team there. Hubble earned admission as a member of the Kentucky bar association, although he reportedly never actually practiced law in Kentucky. Hubble served in the United States Army in World War I, and he quickly advanced to the rank of major. He returned to astronomy at the Yerkes Observatory of the University of Chicago, where he received his Ph.D. in 1917. His dissertation was titled Photographic Investigations of Faint Nebulae.
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.
Hubble died of a 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, Grace Hubble, did not reveal the disposition of his body.
A Brief Summary of Hubble’s 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. 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. Hubble’s discovery, announced on December 30, 1924, fundamentally changed the view of the universe.
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.
Redshift Increases with Distance
Combining his own measurements of galaxy distances based on Henrietta Swan Leavitt’s period-luminosity relationship for Cepheids with Vesto Slipher’s measurements of the redshifts associated with the galaxies, Hubble and Milton L. Humason discovered a rough proportionality of the objects’ distances with their redshifts. Though there was considerable scatter (now known to be due to peculiar velocities), Hubble and Humason were able to plot a trend line from the 46 galaxies they studied and obtained a value for the Hubble-Humason constant of 500 km/s/Mpc, which is much higher than the currently accepted value due to errors in their distance calibrations.
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.
In 1929 Hubble and Humason formulated the empirical Redshift Distance Law of galaxies, nowadays termed simply Hubble’s law, which, if the redshift is interpreted as a measure of recession speed, 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.
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:
[W]e use the term "apparent velocities" in order to emphasize the empirical feature 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, favoring (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."
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 heard of Hubble’s discovery, he said that changing his equations was "the biggest blunder of [his] life".
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 around this time.
His Personal Campaign: Nobel Prize to Include Astrophysics
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.
On March 6, 2008, the United States Postal Service released a 41 cent stamp honoring Hubble on a sheet titled "American Scientists." 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.
More About Hubble’s Law
Hubble’s law is the name for the astronomical observation in physical cosmology first made by Edwin Hubble, that: (1) all objects observed in deep space (interstellar space) are found to have a doppler shift observable relative velocity to Earth, and to each other; and (2) that this doppler-shift measured velocity, of various galaxies receding from the Earth is proportional to their distance from the Earth and all other interstellar bodies. In effect, the space-time volume of the observable universe is expanding (from a smaller past to a larger future); and Hubble’s Law is the direct physical observation of this process, as it unfolds. The law was first derived from the General Relativity equations by Georges Lemaître in 1927. Edwin Hubble derived it empirically in 1929 after nearly a decade of observations. The recession velocity of the objects was inferred from their redshifts, many measured earlier by Vesto Slipher (1917) and related to velocity by him. It is considered the first observational basis for the expanding space paradigm and today serves as one of the pieces of evidence most often cited in support of the Big Bang model.
Combining Redshifts with Distance Measurements
Combining his measurements of galaxy distances with Vesto Slipher’s measurements of the redshifts associated with the galaxies, Hubble discovered a rough proportionality between redshift of an object and its distance. Though there was considerable scatter (now known to be caused by peculiar velocities), Hubble was able to plot a trend line from the 46 galaxies he studied and obtain a value for the Hubble constant of 500 km/s/Mpc (much higher than the currently accepted value due to errors in his distance calibrations).
Fit of redshift velocities to Hubble’s law; patterned
after William C. Keel (2007). The Road to Galaxy
Formation. Berlin: Springer published in association
with Praxis Pub., Chichester, UK. ISBN 3540725342.
At the time of discovery and development of Hubble’s law it was acceptable to explain redshift phenomenon as a Doppler shift in the context of special relativity, and use the Doppler formula to associate redshift z with velocity. Today the velocity-distance relationship of Hubble’s law is viewed as a theoretical result with velocity to be connected with observed redshift not by the Doppler effect, but by a cosmological model relating recessional velocity to the expansion of the universe. Even for small z the velocity entering the Hubble law is no longer interpreted as a Doppler effect, although at small z the velocity-redshift relation for both interpretations is the same.
A New Era for Astronomy Begins
The famous British astrophysicist Stephen Hawking wrote in his book A Brief History of Time that Hubble’s "discovery that the Universe is expanding was one of the great intellectual revolutions of the 20th century." Who could have guessed such a future for Edwin when he began his PhD in Astronomy at Chicago University in 1914?War postpones Hubble’s astronomical debut
Early in 1917, while still finishing the work for his doctorate, Hubble was invited by George Ellery Hale, founder of the Mount Wilson Observatory, in Pasadena, California, to join the staff there. This was a great opportunity, but it came in April of a dreadful year. After sitting up all night to finish his PhD thesis and taking the oral examination the next morning, Hubble enlisted in the infantry and telegraphed Hale:"Regret cannot accept your invitation. Am off to the war."
He served in France and next returned to the United States in 1919. He went immediately to the Mount Wilson Observatory, where the newly discharged Major Hubble, as he invariably introduced himself, arrived, still in uniform, but ready to start observing.
Hubble was lucky enough to be in the right place at the right time. Mount Wilson was the centre of observational work underpinning the new astrophysics, later called cosmology, and the 100-inch Hooker Telescope, then the most powerful on Earth, had just been completed and installed after nearly a decade of work.
On the mountain Hubble encountered his greatest scientific rival, Harlow Shapley, who had already made his reputation by measuring the size of the Milky Way, our own Galaxy. Shapley had used a method pioneered by Henrietta Leavitt at the Harvard College Observatory that relied on the behaviour of standardised light variations from bright stars called Cepheid variables to establish the distance of an object.
His result of 300 000 light-years for the width of the galaxy was roughly 10 times the previously accepted value. However Shapley, like most astronomers of the time, still thought that the Milky Way was all there was to the Universe. Despite a suggestion first made by William Herschel in the 18th century, he shared the accepted view that all nebulae were relatively nearby objects and merely patches of dust and gas in the sky.
The turning point
Hubble had to spend many bitterly cold nights sitting at the powerful Hooker telescope before he could prove Shapley wrong. In October 1923 he spotted what he first thought was a nova star flaring up dramatically in the M31 "nebula" in the constellation of Andromeda. After careful examination of photographic plates of the same area taken previously by other astronomers, including Shapley, he realised that it was a Cepheid star. Hubble used Shapley’s method to measure the distance to the new Cepheid. He could then place M31 a million light-years away – far outside the Milky Way and thus itself a galaxy containing millions of stars. The known Universe had expanded dramatically that day and – in a sense – the Cosmos itself had been discovered!
Even The New York Times of the day realised the importance of the discovery: "Finds spiral nebulae are stellar systems. Doctor Hubbel [sic] confirms view that they are ‘island universes’ similar to our own."
Just the beginning
This discovery was of great importance to the astronomical world, but Hubble’s greatest moment was yet to come. He began to classify all the known nebulae and to measure their velocities from the spectra of their emitted light. In 1929 he made another startling find – all galaxies seemed to be receding from us with velocities that increased in proportion to their distance from us – a relationship now known as Hubble’s Law.
This discovery was a tremendous breakthrough for the astronomy of that time as it overturned the conventional view of a static Universe and showed that the Universe itself was expanding. More than a decade earlier, Einstein himself had bowed to the observational wisdom of the day and corrected his equations, which had originally predicted an expanding Universe. Now Hubble had demonstrated that Einstein was right in the first place.
The now elderly, world-famous physicist went specially to visit Hubble at Mount Wilson to express his gratitude. He called the original change of his beloved equations "the greatest blunder of my life."
Another war stops Hubble again
Hubble worked on indefatigably at Mount Wilson until the summer of 1942, when he left to serve in World War II. He was awarded the Medal of Merit in 1946. Finally, he went back to his Observatory. His last great contribution to astronomy was a central role in the design and construction of the Hale 200-inch Telescope on Palomar Mountain. Four times as powerful as the Hooker, the Hale would be the largest telescope on Earth for decades. In 1949, he was honoured by being allowed the first use of the telescope.
From: SpaceTelescope,org, Edwin Powell Hubble — The Man Who Discovered the Cosmos.
Click HERE to see the slideshow of
Edwin Hubble & his Telescopes.
Please take time to further explore more about XXXXX by accessing the Wikipedia articles referenced below…
References
Other Events on this Day:
In 1853…
James Gadsden, minister to Mexico, signs the Gadsden Purchase, in which the United States buys nearly 30,000 square miles of land from Mexico.In 1862…
The ironclad USS Monitor sinks in a storm off Cape Hatteras, North Carolina.In 1922…
Vladimir I. Lenin proclaims the existence of the Union of Soviet Socialist Republics at the First All-Union Congress of Soviets, transforming the Russian Empire into the communist Soviet Union with the confederation of Russia, Belarus, Ukraine and Transcaucasia.In 1924…
Astronomer Edwin Hubble, an American astronomer, made an announcement that profoundly changed our understanding of the universe by demonstrating the existence of galaxies other than our own, the Milky Way. He also discovered that the degree of "Doppler shift" observed in the light spectra from other galaxies increased in proportion to a particular galaxy’s distance from Earth.In 1940…
California opens its first freeway, the Arroyo Seco Parkway, connecting Los Angeles and Pasadena.In 1951…
The TV western The Roy Rogers Show debuts.In 1986…
The British government announces plans to phase out the use of more than 200 canaries in coal mines, replacing the birds that had alerted miners to toxic underground gases since 1911 with modern carbon monoxide detectors.In 2006…
Former Iraqi President Saddam Hussein is executed by hanging following his Nov. 6 conviction by the Iraqi Special Tribunal of perpetrating crimes against humanity.
Dates and events based on:
William J. Bennett and John Cribb, (2008) The American Patriot’s Almanac Daily Readings on America. (Kindle Edition)
Background information is from Wikipedia articles on:
Wikipedia: Edwin Hubble…
http://en.wikipedia.org/wiki/Edwin_Hubble
Wikipedia: Hubble’s Law…
http://en.wikipedia.org/wiki/Hubble%27s_law
LIFE: Hubble, The Man & His Telescope…
http://www.life.com/image/first/in-gallery/26802/hubble-the-man-and-his-telescope#index/0
Space Telescope: Hubble, The Man Behind the Name…
http://www.spacetelescope.org/about/history/the_man_behind_the_name/
Brainy Quote: EDWIN POWELL HUBBLE Quotes…
http://www.brainyquote.com/quotes/authors/e/edwin_powell_hubble.html
Brainy Quote: COSMOLOGY Quotes…
http://www.brainyquote.com/quotes/keywords/cosmology.html
Other Posts on this Topic:
Prof. Boerner’s Exploration: The Hubble Space Telescope…
http://www.boerner.net/jboerner/?p=11389
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