46: Dark Energy And The End Of The Universe

A century ago, Einstein had a conundrum: his brand new General Theory of Relativity, explaining gravity as warped space-time, predicted a universe either expanding or contracting — yet the cosmos seemed, and was believed by all to be, static. To fix his equations, he added a simple fudge factor, the Cosmological Constant, to balance gravity and keep the universe in place. Hubble then showed that, *actually*, the Universe is expanding after all ... and everyone agreed that Einstein's constant wasn't necessary. Albert himself called it his "biggest blunder". Except, a hundred years later, astronomers found that the universe isn't just expanding ... it's speeding up! The simplest way to account for this in theory is to drag Einstein's blunder out of the bin, dust it off, and give it a new name: Dark Energy. Not a big deal — it only accounts for, what, 70% of the known universe ...