Delay of Light

Until the 17th century the speed of light was thought to be too fast to measure or as argued successfully by the French philosopher René Descartes “infinite” which worked well for early science fiction fantasy authors

• Astronomer Johannes Kepler In his novel “The Dream” published 1634, tells the story of a man named Drukotus who travels to the Moon by the intercession of demons without regard to time or distance.
• Comic History of the States and Empires of the Moon,1657 by Cyrano de Bergerac in turn relates the journey of his protagonist flying to the Moon in a vehicle propelled by chemical reactions, fiction’s first space ship. Again with out consideration of speed or time. 

  

  Ole Rømer

Light speed, was never a consideration for early science fiction fantasy authors until, as luck would have it, Danish astronomer Ole Rømer, quite by accident, discovered the speed of light. Rømer was conducting a series of observations of Jupiter’s moon Io and noticed a curiosity, the moon’s eclipse cycles as recorded on Earth appeared twenty-two minutes later when Earth, in its orbit, was furthest from Jupiter. Using a little math and some knowledge of the diameter of the Earth’s orbit he was able to calculate the speed of light as 131,000 miles per second [later revised to 186,000 MPS based on improved observations of the size of Earth’s orbit].

Due in part to Rømer’s chance findings the speed of light and the great distances that marked the bounds of the universe now imposed severe constraints on science fiction fantasy authors. If nothing could exceed the speed of light then authors were forced to come up with some other explanation for their character’s ability to fly to the far corners of the universe. Had light speed remained infinite, well then surely anything was possible. Science was beginning to intrude on the art of fiction story-telling.

As decades then centuries passed more and more science would inform our concept of the natural laws of the universe making it increasingly difficult for SFF writers to astound their audience. But nothing to date has so refined the genre as Rømer’s delay of light.

H.D. Weikle