In 1572 Tycho Brache observed the first super nova. He showed that the nova was located beyond the moon. He was also the first to produce a modern star guide.

 

In 1572, Danish astronomer Tycho Brahe made one of the most significant astronomical discoveries of his time: the observation of a supernova. This event, known as SN 1572 or Tycho’s Supernova, marked a critical moment in the history of astronomy and changed how humanity understood the universe.

On November 11, 1572, while Brahe was observing the night sky, he noticed a bright new object in the constellation Cassiopeia, one that had not been visible the night before. This “new star,” as it was called, outshone all other stars in the sky and was even visible during the day for several weeks. What made this discovery so extraordinary was that, according to the prevailing Aristotelian worldview, the heavens were believed to be unchanging. The appearance of a new star was considered impossible because, according to this theory, the celestial sphere—the realm beyond the moon—was perfect and immutable.

Tycho Brahe, known for his meticulous and accurate astronomical observations, decided to study this phenomenon in great detail. He carefully measured the position of the new star relative to other known stars over time. Through his observations, Brahe made a groundbreaking discovery: the “new star” did not exhibit any measurable parallax. Parallax is the apparent shift in the position of an object when viewed from different vantage points, and if the nova had been within the Earth’s atmosphere or even within the solar system, it would have shown a noticeable parallax. However, since no such shift was observed, Brahe concluded that the supernova must be located much farther away, well beyond the moon and within the realm of the fixed stars.

This finding had profound implications. By proving that change could occur beyond the lunar sphere, Brahe directly challenged the Aristotelian cosmology, which held that the heavens were immutable. His work contributed to the eventual demise of this ancient view and opened the door for a new understanding of the universe—one that recognized the dynamic and evolving nature of celestial bodies.

Brahe’s detailed study of the supernova was not his only contribution to astronomy. He was also the first to create a modern, accurate star catalogue, which vastly improved the accuracy of star positions compared to previous guides. Before Brahe, most star catalogues relied on ancient observations from Greek astronomers like Hipparchus and Ptolemy, but these were often inaccurate due to centuries of precession—small shifts in the Earth’s orientation that gradually change the positions of stars over time.

Brahe’s star guide, created using the most precise instruments of his era, represented a major advancement. His instruments were large, finely tuned, and mounted in fixed positions, allowing him to take much more accurate measurements than ever before. Brahe’s observations, which were conducted without the aid of a telescope (as this would not be invented until decades later), were so precise that they remained relevant even after telescopic astronomy began to develop.

Although Brahe himself never fully embraced the heliocentric model of the universe proposed by Copernicus, his observations laid the groundwork for future astronomers, including Johannes Kepler, who later used Brahe’s data to formulate the laws of planetary motion. These laws would eventually support the heliocentric theory and revolutionize astronomy.

In summary, Tycho Brahe’s observation of the supernova in 1572 and his subsequent discovery that it lay beyond the moon marked a crucial turning point in the history of astronomy. By challenging the idea of an unchanging cosmos, Brahe opened the way for new astronomical theories and models. His creation of a modern star catalogue also set a new standard for precision in astronomical observations, influencing generations of astronomers who followed in his footsteps.