Joel Weisberg is a professor of physics and astronomy, currently holding title of Herman and Gertrude Stark Professor of Physics and Astronomy and the Natural Sciences. He joined the department in 1984 to replace the retiring Robert Mathews. His research is in the area of radio astronomy, particularly in the study of pulsars.
Weisberg primarily teaches astronomy and astrophysics courses, with Astrophysics I on stellar evolution being his specialty. He also teaches a variety of physics courses and has taught several multidisciplinary courses in the areas of ENTS and science policy.
His research has primarily focused on the binary pulsar star system known as PSR B1913+16. His observations of the system have revealed a decrease in the period of the stars' orbit. These observations are in close agreement with a prediction of Einstein's theory of General Relativity that such a strong gravitational system should produce ripples in space-time known as gravity waves, which radiate energy away from the system. This was the first evidence of the existence of gravity waves, providing an important check on general relativity.
He maintains several research positions for students, often enabling them to travel to various radio observatories. He also built the small Sogn Valley Radio Astronomy Observatory with several students in the mid 1980's using amateur equipment.
In 2008, Weisberg protested the Iraq war at the Republican National Convention in Saint Paul. He was arrested after crossing over a barrier with several other protesters in an act of civil disobedience. 
- "Carleton professor arrested at Republican National Convention" The Carletonian. Sept 26, 2008: 
- "Professor Joel Weisberg appears at court date for RNC protest" The Carletonian. Sept 29, 2009: