The Light Within
Percival Lowell was an American astronomer in the late 1800s. He was convinced there was a Planet X at the outer reaches of our solar system. He never found Planet X, but ultimately Pluto was discovered near where Lowell said it would be.
He was also convinced that there was life on Mars. Through his telescope, he was sure he could see a maze of canal-like structures on the surface of the planet. His writing influenced writers such as H.G. Wells (The War of the Worlds), Robert A. Heinlein (Red Planet), and Ray Bradbury (The Martian Chronicles).
In 1896 Lowell began to study the planet Venus. He noticed a dark spot with spoke-like structures coming from it. There were other features he saw which didn’t correspond to current knowledge of the planet, and he was the only one who saw these features. But he persevered and mapped his observations.
For a century his puzzling observations existed.
Then someone realized that Lowell had been looking into own eye! The explanation: Lowell “shrank the telescope’s exit pupil in front of his eye to a pinhole of diameter less than 0.5 millimeter, effectively turning the telescope into a giant ophthalmoscope that optometrists use to examine eyes of patients.” (Amusing Planet)
In other words, Lowell’s spokes were shadows of the blood vessels in his own retina. Instead of mapping the surface of Venus, he mapped his own eye.
The podcasters who introduced me to this charming story noted that it’s a great example of getting so bogged down in details that you lose the bigger picture.
“Your eye is the lamp of your body. When your eyes are healthy, your whole body also is full of light. But when they are unhealthy, your body also is full of darkness. See to it, then, that the light within you is not darkness. Therefore, if your whole body is full of light, and no part of it dark, it will be just as full of light as when a lamp shines its light on you.” (Luke 11:35-36)
– Ann Iona Warner