Tom Murphy

I am a Professor in the physics department at UCSD, and the Associate Director of CASS, the Center for Astrophysics and Space Sciences. From 2003–2020, I led the APOLLO project as an ultra-precise test of General Relativity using the technique of lunar laser ranging. My interests are transitioning to quantitative assessment of the challenges associated with long-term human success on a finite planet.

In November 2021, I was one of five founders of the Planetary Limits Academic Network, aiming to connect scholars from all disciplines who are concerned about the deep systemic challenges humanity faces this century. Our "launch" paper gives the background, titled Modernity is Incompatible with Planetary Limits: Developing a PLAN for the Future.

In 2014, I started a company (Aircraft Avoidance Systems) to provide safety devices for observatories using lasers for scientific research.

My apologies for a bare-bones and infrequently updated personal page. See also the official bio on the CASS Website.

Energy And Human Ambitions on a Finite Planet

I released a new textbook in March 2021 addressing the challenges facing humanity this century relating to growth, energy resources, and human factors.

The book is available as a free PDF at eScholarship, and as a paperback (at print-cost) at Lulu. A page on this site is also provided for submitting corrections and other feedback.


Selected Publications (PDF)

BASH Compendium: collection of CASS e-mails from Nathan Johnson about weekly social hour

Course Links:


Do the Math Blog on Energy, Growth, Options

Publications on Planetary Limits and Energy

Have a Revolutionary Idea?

If you are contemplating sending your physics idea to me, first try taking this quiz and see how it fares.