John N. Bahcall | |
|---|---|
 | |
| Born | (1934-12-30)December 30, 1934 Shreveport, Louisiana, U.S. |
| Died | August 17, 2005(2005-08-17) (aged 70) New York City,New York, U.S. |
| Resting place | Princeton Cemetery |
| Education | University of California, Berkeley (BA) University of Chicago (MS) Harvard University (PhD) |
| Known for | Solar neutrino problem Hubble Space Telescope |
| Awards | Dannie Heineman Prize for Astrophysics (1994) Dan David Prize (2003) Enrico Fermi Award (2003) |
| Scientific career | |
| Fields | Astrophysics |
| Institutions | Institute for Advanced Study California Institute of Technology Indiana University Harvard University of Chicago |
John Norris Bahcall (December 30, 1934 – August 17, 2005) was an Americanastrophysicist and the Richard Black Professor for Astrophysics at theInstitute for Advanced Study. He was known for a wide range of contributions to solar, galactic and extragalactic astrophysics, including thesolar neutrino problem, the development of theHubble Space Telescope, and his leadership and development of the Institute for Advanced Study inPrinceton.[1][2]
Bahcall was born into a Jewish family inShreveport, Louisiana on December 30, 1934,[3] and would later describe an early aspiration to become aReformrabbi.[4] He did not take science classes at high school.[1] In high school he was a state tennis champion[2] and a national debate champion (1952).[1]
Bahcall began his university studies atLouisiana State University as aphilosophy student on a tennis scholarship, where he considered pursuing the rabbinate. At the end of his freshman year, he transferred to theUniversity of California, Berkeley, still studying philosophy.[1] He took his firstphysics class to fulfill a graduation science requirement, later saying:[5]
"It was the hardest thing I have ever done in my life, but I fell in love with science. I was thrilled by the fact that by knowing physics you could figure out how real things worked, like sunsets and airplanes, and that after a while everyone agreed on what was the right answer to a question."[5]
Bahcall switched majors to physics,[1] and graduated with anAB in Physics from Berkeley in 1956. He obtained hisMS in physics in 1957 from theUniversity of Chicago and hisPhD in physics fromHarvard University in 1961.[1][2]
He spent a year as a research fellow in physics withEmil Konopinski atIndiana University. From 1962 to 1970, he worked with a group led byWilliam Fowler at the Kellogg Laboratory of theCalifornia Institute of Technology,[2] first as a research fellow and later as an assistant and associate professor.[6]
Bahcall joined theInstitute for Advanced Study inPrinceton, New Jersey in 1968[7][1] becoming a professor of natural sciences in 1971 and the Richard Black Professor of Natural Sciences in 1997.[6]
Bahcall became a member of theNational Academy of Sciences in 1976.[8]
He was president of theAmerican Astronomical Society from 1990 to 1992,[5] and was president-elect of theAmerican Physical Society at the date of his death.[9]
Bahcall published over six hundred scientific papers[7] and wrote or edited nine books on astrophysics.[2]
He is most notable for his work in establishing thestandard solar model. He spent much of his life pursuing thesolar neutrino problem withphysical chemistRaymond Davis, Jr. Together, Davis and Bahcall collaborated on theHomestake Experiment. To test Bahcall's theoretical predictions, Davis created an undergrounddetector for neutrinos in aSouth Dakota gold mine, essentially a large tank filled withcleaning fluid. The flux of neutrinos found by the detector was one-third the amount theoretically predicted by Bahcall, a discrepancy that took over thirty years to resolve.[2][10][11] Bahcall's ongoing research in this area resulted in publication of his bookNeutrino Astrophysics (1989), considered a standard reference on solar neutrinos.[1][12]
The 2002Nobel Prize in physics was awarded to Davis andMasatoshi Koshiba for their pioneering work in observing the neutrinos predicted from Bahcall's solar model, thereby vindicating Bahcall's prediction.[13][14]
In addition to his work on solar neutrinos, Bahcall collaborated with Eli Waxman on theWaxman-Bahcall bound for high energy neutrinos. This bound sets a limit on high energy neutrino flux based on the observed flux of high energycosmic rays. It was not possible to verify this prediction until after his death, with the construction of neutrino telescopes capable of detecting very high energy neutrinos, such as theIceCube Neutrino Observatory.[2][1][15]
Another contribution of Bahcall to astrophysics was the development and implementation of theHubble Space Telescope, in collaboration withLyman Spitzer, Jr., from the 1970s through to the period after the telescope was launched in 1990.[2][1] In 1992, Bahcall received theNASA Distinguished Service Medal for this work.[16][17] He reintroduced the traditional method of star counts, as a quantitative tool for assessing galactic structure.[18]
The standard model of a galaxy, with a massiveblack hole surrounded by stars, is known as theBahcall-Wolf model. The Bahcall-Soneira model was for many years the standard model for the structure of theMilky Way. He also contributed to accurate astrophysical models of stellar interiors.[2][1]
Bahcall marriedPrinceton University astrophysics professorNeta Bahcall, whom he met as a graduate student at theWeizmann Institute in the 1960s. They had a daughter and two sons (includingSafi Bahcall).[2][7]
He died in New York on 17 August 2005, from a rare blood disorder.[14][3]
