John Ruhl is a professor of physics at Case Western Reserve University

Case Western Reserve University

Case Western Reserve University is a private research university located in Cleveland, Ohio, USA...

. He received a BS in physics from the University of Michigan

University of Michigan

The University of Michigan is a public research university located in Ann Arbor, Michigan in the United States. It is the state's oldest university and the flagship campus of the University of Michigan...

 in 1987 and a Ph.D. in physics from Princeton

Princeton University

Princeton University is a private research university located in Princeton, New Jersey, United States. The school is one of the eight universities of the Ivy League, and is one of the nine Colonial Colleges founded before the American Revolution....

 in 1993. While a graduate student at Princeton, Ruhl, along with several other graduate students, co-authored the text Princeton Problems in Physics.

Ruhl is an experimentalist in cosmology. He studies the CMB

Cosmic microwave background radiation

In cosmology, cosmic microwave background radiation is thermal radiation filling the observable universe almost uniformly....

 and is currently co-principal investigator on the Spider

Spider CMB

Spider is a balloon-borne experiment designed to search for primordial gravity waves imprinted on the cosmic microwave background . Measuring the strength of this signal puts limits on inflationary theory....

 and South Pole Telescope

South Pole Telescope

The South Pole Telescope is a 10 metre diameter telescope located at the Amundsen-Scott South Pole Station, Antarctica. It is a microwave/millimetre-wave telescope that observes in a frequency range between 70 and 300 GHz...

 projects.

Ruhl was also principal investigator on the ACBAR and Boomerang

BOOMERanG experiment

The BOOMERanG experiment measured the cosmic microwave background radiation of a part of the sky during three sub-orbital balloon flights. It was the first experiment to make large, high fidelity images of the CMB temperature anisotropies...

experiments.

Outside of experimental physics, Ruhl is also the leader of the Institute for Sustainability at Case.