The Universe Was Born on This Day in 4977 B.C., According to Kepler's Ballsy Math

The 16th-century German astronomer's calculation was a bit off, but he deserves credit for daring to try.

If Johannes Kepler were alive today, he’d be celebrating the 6,993rd birthday of the universe. The German mathematician and astronomer, considered one of the founders of modern science, predicted in the 17th century that the universe was created on April 27 in the year 4977 B.C. We know now that Kepler’s math was off by some 13.7 billion years — he can thank the Big Bang theory for usurping his claim — but the accuracy of his calculations is less important than the audacity it took to make them.

Daring to assign the universe a birthday in an era in which heliocentrists were condemned by the Catholic church was an act as bold as his claim itself. Forget celebrating birthdays — let’s toast Kepler’s balls.

"Ptolemy can suck it."


Kepler, born on December 27, 1571 in Weil der Stadt, Germany, came forth into a world that still looked to Ptolemy — the father of geocentricity — for explanations about the universe.

But by the time Kepler graduated from the University of Linz, he’d already studied the works of Nicolaus Copernicus, who soon believed the planets revolved around the Sun. Kepler soon became a full-fledged Copernican, studying the Polish astronomer’s works under the guidance of his first mentor, Professor Michael Maestlin. He kept his ideas quiet, though, as publicly supporting heliocentric theories was, at the time, considered professional suicide.

By taking the Copernican model to heart, Kepler cultivated an unshakeable scientific platform on which to build his theories of planetary movement — and galactic birthdays — that he published later in his career.

His knowledge of mathematics and astronomy expanded rapidly after he graduated. Kepler went on to study the mathematical underpinnings of the orbit of Mars under the Danish astronomer and mathematician Tycho Brahe, later inheriting his supervisor’s painstakingly compiled astronomy data.

In time, he became a contemporary of Galileo’s, publicly praising the Italian astronomer’s paper on Jupiter’s moons in an response article titled “Conversations with the Starry Messenger.” (Galileo, rather shadily, did not respond publicly to Kepler’s published works.)

After years spent immersed in the worlds of astronomy and mathematics, Kepler decided, in 1609, to give back, publishing the first two of his three laws of planetary motion. These laws predicted that planets take an elliptical — not circular — pathway around the Sun, speeding up as their orbits bring them close to the solar system’s center and slowing down as they move away. The same body of knowledge that led to these theories of the universe also led him to calculate the birthdate of the universe as April 27 — incidentally, the same date as his wedding anniversary to the German heiress Barbara Müller — in the year 4977 B.C.

Did his calculations lead him to the date, or could his theory of the birth of the universe just be a thinly veiled (and, let’s be real, pretty romantic) anniversary present to his wife? We’ll probably never know. But we can raise a glass to it anyway.

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