IMAGINE driving along a straight road full of potholes. Very likely, you will have to endure swerves and bumps to reach your destination. Something similar could be happening to light travelling through the vacuum of space: it surges ahead in places and takes diversions at others, because the fabric of space-time is thought to be “foamy” rather than smooth. Soon, the world’s largest telescopes could look for this effect, perhaps allowing us to glimpse the very nature of space-time for the first time.
Quantum theory says that at scales below 10-35 metres (known as the Planck scale), space-time…
