You’re probably familiar with plenty of optical illusions, from the Necker cube to the dress that broke the internet.
We’ve been discovering such illusions for hundreds of years; in fact, researchers at the University of Oslo recently discovered a particularly fascinating one. Dubbed “the expanding hole illusion,” this still image of a black hole seemingly grows over time — and it’s so powerful that 86 percent of those who experience the illusion experience pupil dilation in anticipation of reduced light.
