Understanding the darkness — maybe a poet does that better than a scientist? Everyone probably knows that scientists sometimes are active in the field of humanities, there are scientists who have made important humanistic contributions. But not everyone knows that there are also humanists who have solved difficult scientific problems.
Sometimes the easiest questions are the most difficult:
Why is the sky black at night?
If the universe is infinitely large and there are infinitely many stars that are randomly placed, then there should be a star at every point in the sky and the sky would be completely covered by stars. The night sky should not be black but filled with stars without spaces, a sparkling, radiant, silvery-white night.
It sounds like a simple question; everybody knows that when the sun has set the sky is dark black. But the question is not simple the answer is far from obvious. Instead, it puzzled scientists for hundreds of years.
The riddle is called Olbers’ paradox, named after Henrich Wilhelm Olbers a German amateur astronomer who in 1823 wrote an article in which he formulated the paradox. His proposed solution was that there would be some type of black cloud that absorbed radiation and thereby hid some of the stars from us. But there are no such black clouds in the skies.
The problem is very old, it puzzled the first modern astronomers. In England in the 16th century worked Thomas Digges, a careful explorer of the starry sky. He is probably the first to describe the problem and provided a possible solution. Digges imagined that the distant stars would somehow become so faint that they could not be seen on Earth. But light cannot disappear on the way towards earth.
Even the basic conditions have been questioned — the universe may not be infinite. The great astronomer Johannes Kepler, who solved the problem of the planets’ orbits and who managed to calculate that the planets move in elliptical orbits around the sun, said in the early 17th century that the dark sky was proof that the universe is not…