A rainbow is a full circle, but from the ground, we only see part of the arc. The “end” that seems to touch the earth is an optical illusion that changes based on the observer’s position.

As the anticipation builds for this sacred holiday, many are already preparing for the traditions that define Easter — from ...

Now science wants to tell us that it's merely an optical illusion? That's the suggestion behind the argument that purple ...

A Brocken spectre optical illusion happens when a person's own shadow is projected onto low cloud, often surrounded by a rainbow halo. Lauren Wood, a mountain leader from Menai Bridge, Anglesey ...