Why is space black and not white? Edgar Allen Poe (yes, THAT Edgar Allen Poe) answered the question.
The question of why space is black and not white is a fascinating one that has puzzled astronomers and philosophers for centuries. Edgar Allan Poe, the renowned American writer, was one of the first to propose a scientifically reasonable answer to this question. In his essay “Eureka” (1848), Poe suggested that the universe is not old enough to fill the sky with light.
The Finite Age of the Universe
Poe’s idea was that the universe is finite in age, and the speed of light is finite. As a result, only a finite number of stars can be observed from Earth, despite the universe being potentially infinite in size. This means that the light from distant stars has not had time to reach us yet, leaving the sky dark.
The Scattering of Light
Another reason why space appears black is due to the scattering of light. During the day, the blue light from the Sun is scattered by the Earth’s atmosphere, making the sky appear blue. At night, when the part of the Earth is facing away from the Sun, there is no nearby bright source of light to scatter, resulting in a dark sky.
Olbers’ Paradox
The paradox is often attributed to Heinrich Wilhelm Olbers, who described it in 1823. However, it was actually Edgar Allan Poe who provided a more satisfactory resolution to the paradox in his essay “Eureka”. Poe’s idea was that the finite age of the universe and the finite speed of light mean that only a finite number of stars can be observed from Earth, resolving the apparent paradox.
The Steady State Theory
In the Steady State theory, the universe is infinitely old and uniform in time as well as space. This theory proposes that the universe is constantly expanding, causing the light from distant stars and quasars to redshift. As a result, the total light flux from the sky remains finite, explaining why space appears dark.
In conclusion, the combination of the finite age of the universe, the scattering of light, and the Steady State theory all contribute to why space appears black and not white. Edgar Allan Poe’s insight into the finite age of the universe was a crucial step in resolving the paradox of the dark sky.