John Norris Bahcall (December 30, 1934 – August 17, 2005) was an American astrophysicist and the Richard Black Professor for Astrophysics at the Institute for Advanced Study.

[1][2] Bahcall was born into a Jewish family in Shreveport, Louisiana on December 30, 1934,[3] and would later describe an early aspiration to become a Reform rabbi.

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.

From 1962 to 1970, he worked with a group led by William Fowler at the Kellogg Laboratory of the California Institute of Technology,.

He spent much of his life pursuing the solar neutrino problem with physical chemist Raymond Davis, Jr.

To test Bahcall's theoretical predictions, Davis created an underground detector for neutrinos in a South Dakota gold mine, essentially a large tank filled with cleaning 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.