Controversy Erupts over Expansion of Universe: Nobel Prize Awarded in Error?

In 2011, three physicists won the Nobel Prize for showing that the expansion of the universe speeds up, which is usually attributed to aa mysterious type of energy called “dark energy”. But last year, though, a different group published research showing that universal expansion isn’t actually getting faster. Since then, the two groups have engaged in a whole bunch of back-and-forth refuting each other’s claims and now a third one has chimed in. Let’s take a look.