Do we actually see an inverted universe?
We open our eyes each morning and trust what we see. The trees sway upright, the sky arches overhead, and people walk right side up. But beneath this comforting familiarity lies one of the most fascinating truths in physics and neuroscience: what we see may not be how things are . In fact, we may be viewing the universe... upside down. Sounds strange? Let’s unfold this visual mystery. The Cosmic Microwave Background, pictured here, is the most ancient thing we can see in space. But what's hiding behind it? (Image credit: ESA and the Planck Collaboration) The Physics of Light: Inversion Begins To understand why our perception is ‘inverted,’ we need to start with how light behaves. Light travels in straight lines. When it bounces off objects and enters our eyes, it passes through the cornea and lens, which work together to bend (or refract) the light rays. This bending causes the image projected onto the retina at the back of our eyeballs to be inverted —flipped both vertical...