| Revision as of 17:46, 24 July 2014 editAnomieBOT (talk | contribs)Bots6,559,963 editsm Dating maintenance tags: {{NPOV-section}}← Previous edit | Revision as of 19:21, 24 July 2014 edit undoPrimefac (talk | contribs)Edit filter managers, Autopatrolled, Bureaucrats, Checkusers, Oversighters, Administrators208,883 edits →Inflationary theory: hopefully I have made everyone happy - Guth found one theory was wrong, but continued working on inflation theory. Linde's interview is not necessary anymoreNext edit → | ||
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| ==Inflationary theory== | ==Inflationary theory== | ||
| {{Refimprove section|date=July 2014}} | |||
| Guth's first step to developing his theory of inflation occurred at Cornell in 1978, when he attended a lecture by ] about the ] of the universe.<ref>]. </ref> Dicke explained how the flatness problem showed that something significant was missing from the Big Bang theory at the time. The fate of the universe depended on its density. If the density of the universe was large enough, it would collapse into a ], and if the actual density of the matter in the cosmos was lower than the critical density, the universe would increasingly get much bigger. | Guth's first step to developing his theory of inflation occurred at Cornell in 1978, when he attended a lecture by ] about the ] of the universe.<ref>]. </ref> Dicke explained how the flatness problem showed that something significant was missing from the Big Bang theory at the time. The fate of the universe depended on its density. If the density of the universe was large enough, it would collapse into a ], and if the actual density of the matter in the cosmos was lower than the critical density, the universe would increasingly get much bigger. | ||
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| Two weeks later, Guth heard colleagues discussing something called the ]. The microwave background radiation discovered by ] and ] appeared extremely ], with almost no variance. This seemed very paradoxical because, when the radiation was released about 300,000 years after the Big Bang, the observable universe had a diameter of 90 million ]s. There was no time for one end of the cosmos to communicate with the other end, because energy can not move faster than the speed of light. The paradox was resolved, as Guth soon realized, by the inflation theory. Since inflation started with a far smaller amount of matter than the Big Bang had presupposed, an amount so small that all parts would have been in touch with each other. The universe then inflated at billion times the speed of light so the homogeneity remained unbroken. The universe after inflation would have been very uniform even though the parts were not still in touch with each other. | Two weeks later, Guth heard colleagues discussing something called the ]. The microwave background radiation discovered by ] and ] appeared extremely ], with almost no variance. This seemed very paradoxical because, when the radiation was released about 300,000 years after the Big Bang, the observable universe had a diameter of 90 million ]s. There was no time for one end of the cosmos to communicate with the other end, because energy can not move faster than the speed of light. The paradox was resolved, as Guth soon realized, by the inflation theory. Since inflation started with a far smaller amount of matter than the Big Bang had presupposed, an amount so small that all parts would have been in touch with each other. The universe then inflated at billion times the speed of light so the homogeneity remained unbroken. The universe after inflation would have been very uniform even though the parts were not still in touch with each other. | ||
| Guth first made public his ideas on inflation in a seminar at SLAC on 23 January 1980. In August, he submitted his paper, entitled "The Inflationary Universe: A Possible Solution to the Horizon and Flatness Problems" to the journal '']''.<ref name="Inflationary Universe">{{cite journal| |
Guth first made public his ideas on inflation in a seminar at SLAC on 23 January 1980. He ignored magnetic monopoles because they were based on assumptions of GUT, which was outside the scope of the speech. In August, he submitted his paper, entitled "The Inflationary Universe: A Possible Solution to the Horizon and Flatness Problems" to the journal '']''.<ref name="Inflationary Universe">{{cite journal|last1=Guth|first1=Alan H.|title=Inflationary universe: A possible solution to the horizon and flatness problems|journal=Physical Review D|volume=23|issue=2|pages=347–356|doi=10.1103/PhysRevD.23.347}}</ref> In this paper Guth postulated that the inflation of the universe could be explained if the universe were supercooled 28 orders of magnitude below the critical temperatures required for a phase change. | ||
| In December 1981, Guth read a paper from Moscow physicist ] saying that the whole universe is within just one bubble, so nothing is destroyed by wall collisions. This conclusion was made using a ] with an energy graph that was originally proposed by ] and ]. Guth discussed this with Linde, who had independently been working on bubble inflation, but without considering the flatness problem. Linde and Guth eventually exchanged papers on the subject. | In December 1981, Guth read a paper from Moscow physicist ] saying that the whole universe is within just one bubble, so nothing is destroyed by wall collisions. This conclusion was made using a ] with an energy graph that was originally proposed by ] and ]. Guth discussed this with Linde, who had independently been working on bubble inflation, but without considering the flatness problem. Linde and Guth eventually exchanged papers on the subject. | ||
| By 1983 Guth had published a paper describing how his supercooled-universe scenario was not ideal, as the "triggering mechanism" to exit such a state would require "extreme fine tuning of parameters" and felt a more natural solution was required.<ref>{{cite journal|last1=Guth|first1=Alan H.|last2=Weinberg|first2=Erick J.|title=Could the universe have recovered from a slow first-order phase transition?|journal=Nuclear Physics B|volume=212|issue=2|pages=321–364|doi=10.1016/0550-3213(83)90307-3}}</ref><ref name=LindeSciAm> by Andrei Linde, Scientific American, Volume 9, Issue 1 (1998) 98-104.</ref> However, this did not deter him from the belief that the universe expanded exponentially in a vacuum in its early lifetime.<ref>{{cite journal|last1=GUTH|first1=ALAN H.|title=The New Inflationary Universe|journal=Annals of the New York Academy of Sciences|volume=422|issue=1 Eleventh Texa|pages=1–14|doi=10.1111/j.1749-6632.1984.tb23336.x}}</ref> | |||
| ===Guth's recanting of inflation theory=== | |||
| {{NPOV-section|talk=Alan Guth#Guth's recanting of inflation theory|date=July 2014}} | |||
| According to ] in his , Guth has recanted his inflation theory, in a paper more than 100 pages long.<ref>, interview with Clive Cookson. The Financial Times, 11 April 2014.</ref> | |||
| Linde has been noted for stating this before as well, like in his ] article in which he explicitly stated: "''After investigating his model for a year, Guth finally renounced it in a paper he co-authored with Erick J. Weinberg of Columbia University''".<ref name=LindeSciAm> by Andrei Linde, Scientific American, Volume 9, Issue 1 (1998) 98-104.</ref> | |||
| The Guth's ''Astrophysics Kavli prize'' citation states basically that Guth’s model was flawed as he himself recognized.<ref>, Kavli Foundation Website.</ref> | |||
| ==Current life== | ==Current life== | ||
Revision as of 19:21, 24 July 2014
| Alan Harvey Guth | |
|---|---|
 Alan Guth at Trinity College, Cambridge, 2007 | |
| Born | (1947-02-27) 27 February 1947 (age 77) New Brunswick, New Jersey |
| Nationality | American |
| Alma mater | Massachusetts Institute of Technology |
| Known for | Cosmic inflation |
| Awards | MIT School of Science Prize for Undergraduate Teaching,
Oscar Klein Medal (1991), The Franklin Medal for Physics of the Franklin Institute, Isaac Newton Medal of Institute of Physics (2009), Dirac Prize of the International Center for Theoretical Physics in Trieste, Cosmology Prize of the Peter Gruber Foundation (2004), Fundamental Physics Prize (2012). Kavli Prize (2014). |
| Scientific career | |
| Fields | Cosmology, Theoretical physics, Particle physics |
| Institutions | Princeton Columbia Cornell Stanford Linear Accelerator MIT |
| Doctoral advisor | Francis E. Low |
Alan Harvey Guth (born 27 February 1947) is an American theoretical physicist and cosmologist. Guth has researched elementary particle theory (and how particle theory is applicable to the early universe). He is currently serving as Victor Weisskopf Professor of Physics at the Massachusetts Institute of Technology. According to some sources, Guth is the originator of the inflationary universe theory; however, according to other sources, the originator was Alexei Starobinsky.
He graduated from MIT in 1968 in physics and stayed to receive a master's and a doctorate, also in physics.
As a junior particle physicist, Guth developed the idea of cosmic inflation in 1979 at Cornell and gave his first seminar on the subject in January 1980. Moving on to Stanford University Guth formally proposed the idea of cosmic inflation in 1981, the idea that the nascent universe passed through a phase of exponential expansion that was driven by a positive vacuum energy density (negative vacuum pressure). The results of the WMAP mission in 2006 made the case for cosmic inflation very compelling. Measurements by the BICEP and Keck Array telescope give support to the idea of cosmic inflation, preliminary confirmation of which was given on 17 March 2014, with the findings of the B-mode polarization signature. However, on 19 June 2014, lowered confidence in confirming the cosmic inflation findings was reported.
Early life
Alan Guth was born on 27 February 1947 in New Brunswick, New Jersey. After his junior year at Massachusetts Institute of Technology, he enrolled in a five-year program where he could get his bachelor’s and master’s after two more years. Guth obtained a bachelor’s and master’s degree in 1969 and a doctorate in 1972. In 1971, he married Susan Tisch, his high school sweetheart. They have two children: Lawrence (born 1977) and Jennifer (born 1983).
Guth was at Princeton 1971 to 1974, Columbia 1974 to 1977, Cornell 1977 to 1979, and the Stanford Linear Accelerator Center (SLAC) 1979 to 1980. Like many other young physicists of the baby boom era, he had a hard time finding a permanent job, because there were far fewer assistant professorships than there were young scientists seeking such jobs, a phenomenon that has been referred to as the “generation of lost scholars.”
At the start of his career, Guth studied particle physics, not cosmology. Guth's earliest work at Princeton was in the study of quarks, the elementary particles that make up protons and neutrons. At Columbia, Guth studied grand unification (GUTs), focusing on the phase transitions generated by spontaneous symmetry breaking. Most GUTs predict the generation of magnetic monopoles during spontaneous symmetry breaking, but none had ever been detected - the monopole problem.
Inflationary theory
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Guth's first step to developing his theory of inflation occurred at Cornell in 1978, when he attended a lecture by Robert Dicke about the flatness problem of the universe. Dicke explained how the flatness problem showed that something significant was missing from the Big Bang theory at the time. The fate of the universe depended on its density. If the density of the universe was large enough, it would collapse into a singularity, and if the actual density of the matter in the cosmos was lower than the critical density, the universe would increasingly get much bigger.
The next part in Guth's path came when he heard a lecture by Steven Weinberg in early 1979. Weinberg talked in two lectures about the Grand Unified Theory (GUT) that had been developed since 1974, and how it could explain the huge amount of matter in the universe compared to the amount of antimatter. The GUT explained all the fundamental forces known in science except for gravity. It established that in very hot conditions, such as those after the Big Bang, electromagnetism, the strong nuclear force, and the weak nuclear force were united to form one force. Weinberg also was the one who emphasized the idea that the universe goes through phase transitions, similar to the phases of matter, when going from high energy to low energy. Weinberg’s discussion of why matter is so dominant over anti-matter showed Guth how precise calculations about particles could be obtained by studying the first few seconds of the universe.
Guth decided to solve this problem by suggesting a supercooling during a delayed phase transition. This seemed very promising for solving the magnetic monopole problem. By the time they came up with that, Guth had gone to the Stanford Linear Accelerator Center for a year, but Guth had been talking to Henry Tye back and forth. Tye suggested that they check that the expansion of the universe would not be affected by the supercooling. In the supercooled state, a false vacuum is produced. The false vacuum is a vacuum in the sense that it is state of the lowest possible density of energy; it is false in the sense that it is not a permanent state of being. False vacuums decay, and Guth was to find that the decay of the false vacuum at the beginning of the universe would produce amazing results, namely the exponential expansion of space. This solved the monopole problem, since the expansion dilutes the monopole density.
Guth realized from his theory that the reason the universe appears to be flat was that it was fantastically big, just the same way the spherical Earth appears flat to those on its surface. The observable universe was actually only a very small part of the actual universe. Traditional Big Bang theory found values of omega near one to be puzzling, because any deviations from one would quickly become much, much larger. In inflation theory, no matter where omega starts, it would be driven towards equal to one, because the universe becomes so huge. In fact, a major prediction of inflationary theory is that omega will be found to be one.
Two weeks later, Guth heard colleagues discussing something called the horizon problem. The microwave background radiation discovered by Arno Penzias and Robert Woodrow Wilson appeared extremely uniform, with almost no variance. This seemed very paradoxical because, when the radiation was released about 300,000 years after the Big Bang, the observable universe had a diameter of 90 million light-years. There was no time for one end of the cosmos to communicate with the other end, because energy can not move faster than the speed of light. The paradox was resolved, as Guth soon realized, by the inflation theory. Since inflation started with a far smaller amount of matter than the Big Bang had presupposed, an amount so small that all parts would have been in touch with each other. The universe then inflated at billion times the speed of light so the homogeneity remained unbroken. The universe after inflation would have been very uniform even though the parts were not still in touch with each other.
Guth first made public his ideas on inflation in a seminar at SLAC on 23 January 1980. He ignored magnetic monopoles because they were based on assumptions of GUT, which was outside the scope of the speech. In August, he submitted his paper, entitled "The Inflationary Universe: A Possible Solution to the Horizon and Flatness Problems" to the journal Physical Review. In this paper Guth postulated that the inflation of the universe could be explained if the universe were supercooled 28 orders of magnitude below the critical temperatures required for a phase change.
In December 1981, Guth read a paper from Moscow physicist Andrei Linde saying that the whole universe is within just one bubble, so nothing is destroyed by wall collisions. This conclusion was made using a Higgs field with an energy graph that was originally proposed by Sidney Coleman and Erick Weinberg. Guth discussed this with Linde, who had independently been working on bubble inflation, but without considering the flatness problem. Linde and Guth eventually exchanged papers on the subject.
By 1983 Guth had published a paper describing how his supercooled-universe scenario was not ideal, as the "triggering mechanism" to exit such a state would require "extreme fine tuning of parameters" and felt a more natural solution was required. However, this did not deter him from the belief that the universe expanded exponentially in a vacuum in its early lifetime.
Current life
In the past Guth has studied lattice gauge theory, magnetic monopoles and instantons, Gott time machines, and a number of other topics in theoretical physics. Much of Guth's current work includes extrapolating density fluctuations arising from various versions of inflation, to test against observations, and investigating inflation in "brane world" models.
Guth is the Victor F. Weisskopf Professor of Physics at the Massachusetts Institute of Technology (MIT). So far, he has written about 60 technical papers related to the effects of inflation and its interactions with particle physics. He has won many awards and medals, including the Medal of the International Center for Theoretical Physics, Trieste, Italy, with Andrei Linde and Paul Steinhardt and the Eddington Medal in 1996, and the 2009 Isaac Newton Medal, awarded by the British Institute of Physics.
In 2005 Guth won the award for the messiest office, organised by the Boston Globe. He was entered by colleagues who hoped it would shame him into tidying up, but Guth is quite proud of the award.
Honors and awards
In July 2012, he was an inaugural awardee of the Fundamental Physics Prize, the creation of physicist and internet entrepreneur, Yuri Milner.In 2014, he was a co-recipient of the Kavli Prize awarded by the Norwegian Academy of Science and Letters with Andrei Linde of Stanford University, and Alexei Starobinsky of the Landau Institute for Theoretical Physics.
Publications
- Guth, Alan, "The Inflationary Universe: The Quest for a New Theory of Cosmic Origins". 1997. ISBN 0-201-32840-2 or ISBN 0-224-04448-6
See also
References
- PBS Unsolved Mysteries
- New York Times, 16 March 2006. "Scientists Get Glimpse of First Moments After Beginning of Time"
- ^ The Self-Reproducing Inflationary Universe by Andrei Linde, Scientific American, Volume 9, Issue 1 (1998) 98-104.
- Starobinskii, A.A. (5 December 1979). "Spectrum of relict gravitational radiation and the early state of the universe" (http://www.jetpletters.ac.ru/ps/1370/article_20738.pdf). JETP. 30 (11): 682. Retrieved 14 June 2014.
{{cite journal}}: External link in|format= - Guth, Alan H. (1997), The Inflationary Universe, Reading, Massachusetts: Perseus Books, ISBN 0-201-14942-7
- SLAC seminar, "10-35 seconds after the Big Bang", 23 January 1980. see Guth (1997), pg 186
- Overbye, Dennis. "Space Ripples Reveal Big Bang's Smoking Gun". New York Times. Retrieved 19 March 2014.
- Overbye, Dennis (24 March 2014). "Ripples From the Big Bang". New York Times. Retrieved 24 March 2014.
- BICEP2 Collaboration. "BICEP2 I: Detection Of B-mode Polarization at Degree Angular Scales". arXiv.org. Retrieved 19 March 2014.
{{cite web}}: CS1 maint: numeric names: authors list (link) - Overbye, Dennis (19 June 2014). "Astronomers Hedge on Big Bang Detection Claim". New York Times. Retrieved 20 June 2014.
- Amos, Jonathan (19 June 2014). "Cosmic inflation: Confidence lowered for Big Bang signal". BBC News. Retrieved 20 June 2014.
- Ade, P.A.R. et al (BICEP2 Collaboration) (19 June 2014). "Detection of B-Mode Polarization at Degree Angular Scales by BICEP2" (PDF). Physical Review Letters. 112: 241101. arXiv:1403.3985. Bibcode:2014PhRvL.112x1101A. doi:10.1103/PhysRevLett.112.241101. Retrieved 20 June 2014.
{{cite journal}}: External link in|format= - (1978) Carnegie Council on Policy Studies in Higher Education, “Preserving a Lost Generation: Policies to Assure a Steady Flow of Young Scholars Until the Year 2000”; http://pages.stern.nyu.edu/~rradner/publishedpapers/42PreservingLostGeneration.pdf Downloaded 2011-07-09
- Timothy Ferris. Coming of Age in the Milky Way, p. 356
- Guth, Alan H. "Inflationary universe: A possible solution to the horizon and flatness problems". Physical Review D. 23 (2): 347–356. doi:10.1103/PhysRevD.23.347.
- Guth, Alan H.; Weinberg, Erick J. "Could the universe have recovered from a slow first-order phase transition?". Nuclear Physics B. 212 (2): 321–364. doi:10.1016/0550-3213(83)90307-3.
- GUTH, ALAN H. "The New Inflationary Universe". Annals of the New York Academy of Sciences. 422 (1 Eleventh Texa): 1–14. doi:10.1111/j.1749-6632.1984.tb23336.x.
- Amazon review which mention the award
- Boston Globe photos of winning entry
- Alexander Vilenkin, Many Worlds in One: The Search for Other Universes, ISBN 978-0-8090-9523-0, page 51 for photo'.
- New annual US$3 million Fundamental Physics Prize recognizes transformative advances in the field, FPP, accessed 1 August 2012
- "Nine Scientists Share Three Kavli Prizes".
External links
- Alan H. Guth's webpage at MIT
- MIT Physics Department website
- MIT Center for Theoretical Physics
- Alan Guth - "Eternal inflation: Successes and questions"
- The Growth of Inflation, Symmetry magazine, December 2004/January 2005
- Guth's Grand Guess, Discover magazine, April 2002
- Additional photo
- Inflationary spacetimes are not past-complete