We don’t really dwell on the fact that we exist in the third dimension. Front and back, left and right, up and down. These are the axes by which we navigate the world. When we try to imagine something different, it usually brings to mind images of the wildest science fiction: images of portals in the fabric of space-time and parallel worlds.
But serious physicists have long been fascinated by the possibility of extra dimensions. Even though they are all intangible, they promise to answer some of the biggest questions about the deepest workings of the universe. Moreover, we cannot exclude them simply because they are difficult to imagine and even more difficult to observe. “There’s no reason it has to be three,” says Georges Oviedo of the University of Oxford. “It might have been twice. It might have been 4 o’clock or 10 o’clock.”
Still, there comes a time when every self-respecting physicist looks for hard evidence. That’s why it’s so interesting that over the past few years, researchers have developed several techniques that can finally capture extradimensional evidence. For example, we might discover in the future that gravity is leaking through them. We might see subtle traces of it in black holes, or find traces of it in particle accelerators.
But now, in an unexpected twist, Oviedo and colleagues are claiming an additional dimension that is fundamentally different from what we have so far concocted. This “dark dimension” is thought to contain ancient particles that could solve the mystery of dark matter, whose gravity is thought to have shaped the universe. Importantly, it is also relatively important.
(Tag translation) general relativity
