DARK ENERGY

THE MOST DOMINANT FORCE IN THE UNIVERSE IS ALSO ITS MOST MYSTERIOUS AND MOST UNANTICIPATED

- Robert Lea

You have to feel for physicists at the end of the 19th century. After massive advances in physics in the previous 100 years, many thought they had a good handle on the laws of the universe and all that remained for them to do was make more precise measurements. Quickly, the 20th century began to deliver insights that turned this confidence on its head. Arguably, the most shocking of those discoveries came at the end of the century, when it was found that the universe is expanding and that expansion is accelerating. The force behind this was labelled 'dark energy', but that's just a placeholder. Troublingly, dark energy isn't just an aspect of the cosmos, it's the dominating aspect. And it's something that can't be ignored, as the nature of dark energy could decide what happens at the end of the universe.

Fittingly, scientists are in the dark about what dark energy actually is. Luz Ángela García Peñaloza is a cosmologist at Universidad ECCI in Colombia who has spent the last decade trying to understand it. "It's like looking for a needle in a haystack," she tells All About Space. "Except with a needle, you know what it looks like, and you know what it will feel like when it pricks your finger. With dark energy, we don't know what we are looking for. It's a bit hilarious in the sense that we are studying something we just aren't seeing. But Understanding dark energy will help us understand so many fundamental questions."