“Dark energy” is one of the more unfortunate names in science. You’d think it has something to do with dark matter (itself a misnomer), but it has the opposite effect: while dark matter drives the clumping-up of material that makes galaxies, dark energy pushes the expansion of the Universe to greater and greater rates. Though we should hate on the term “dark energy”, we should respect Michael Turner, the excellent cosmologist who coined the phrase. He is also my academic “grand-advisor”: he supervised Arthur Kosowsky’s PhD, and Arthur in turn supervised mine.

And of course, I worked on dark energy as a major part of my PhD research. In my latest piece for Slate, I describe a bit of my dysfunctional relationship with cosmic acceleration, and why after 16 years dark energy is still a matter of frustration for many of us.

Because dark energy doesn’t correspond easily to anything in the standard toolkit of physics, researchers have been free to be creative. The result is a wealth of ideas, some that are potentially interesting and others that are frankly nuts. Some string theorists propose that our observable universe is the result of a vast set of parallel universes, each with a different, random amount of dark energy. Other physicists think our cosmos is interacting with a parallel universe, and the force between the two drives cosmic acceleration. Still others suspect that dark energy is a sign that our currently accepted theory of gravity—Einstein’s general theory of relativity—is incomplete for the largest distances. [Read more…]