Eric L. Michelsen

Eric L. Michelsen, PhD studies and teaches fundamental physics at UCSD and is a frequent public speaker. He is very interested in education, especially science education. His book, Quirky Quantum

Concepts, was published by Springer in February 2014. He got his PhD in Physics at UCSD in June 2010 on an experiment testing Einstein's theory of gravity (General Relativity). The experiment traces out the orbit of the moon with a laser, often to 1 mm accuracy (the thickness of a dime). In a former life, Eric was an electrical engineer in semiconductors and communication systems. He has helped start three successful companies, including two venture-funded firms. At home, he has a wife, and two children who ask him lots of questions that he can't answer.

Sharp Minds June 3, 2024 Lecture Topic

Shooting the Moon—Getting Down with Gravity

The APOLLO (Apache Point Observatory Luna Laser-ranging Operation) project provides the best test of gravity in the world: we measure the distance to the moon (250,000 miles) to within the thickness of a dime using a powerful laser shined through a large telescope. This is an important test of Einstein's General Relativity, and so far, Einstein's theory passes with flying colors. We explain this exciting project, how it works, and some of its challenges and successes.

Einstein's theory predicts the moon's orbit very precisely and this gives us a way to check the theory. To get to this accuracy we have to consider many subtle effects such as the moon's liquid core, earth tides, changes to the length of our day caused by recent earthquakes, etc. I will give an overview of the experiment, the cutting-edge technology used, and the scientific discoveries that we have made and are hoping for.