Dark Energy and Einstein’s Biggest Blunder

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Speaker(s): Thomas Helliwell

According to quantum field theory, vacuum is not nothing, but probably contains an enormous amount of energy. A primary effect of this energy should be on gravitation on a cosmological scale. In fact, in 1917 Einstein introduced something very similar into his gravitational field equations, the so-called “cosmological constant”, to overcome what he thought was a flaw in the equations. He soon came to regret the change he had made, calling it “my biggest blunder.” Was it a blunder or not? Recent observations show that the cosmological constant seems to be there after all, but its observed size is so far removed from the predictions of quantum field theory that its nature poses the most far-reaching unsolved problem in physics. Does its observed size have anything to do with the fact that we are here to observe it?

Colloquium

Junior and senior physics majors attend our biweekly colloquium series, held on Tuesday afternoons at 4:30 p.m. in Shanahan B460. The talks are open to all students and to the public, and are frequently attended by scientists from the other Claremont Colleges, Cal Poly Pomona, and others. The series features speakers from a broad range of institutions and fields of physics.