nova / supernova

Today, novas and supernovas (or supernovae) are considered to be distinct phenomenon. But prior to the 1930s, the term nova was applied to both. In current usage, nova occurs in binary star systems consisting of a white dwarf star and a larger star where the white dwarf is accreting material, mostly hydrogen, from its larger companion. When the white dwarf reaches a critical mass, it blows off the excess material in a violent explosion. When this results in the destruction of the white dwarf, it is classified as a Type 1a supermova.

A regular supernova, on the other hand, is the last stage in the life of massive star. When the star is no longer able to sustain a fusion reaction sufficient to counteract its own gravity, it implodes. This gravitational collapse triggers a sudden outburst of fusion reactions that result in a tremendous explosion, destroying the star.

The term nova is from the Latin meaning new because either of these two phenomena appear, from the perspective of an observer on earth, to be a new star.

The coining of nova to refer to an exploding star is often credited to the astronomer Tycho Brahe, but this is not quite correct. Brahe was one of many around the world who observed what we now know to have been a Type 1a supernova in the constellation of Cassiopeia in the year 1572 (SN 1572). Many commentaries and histories conflate two different texts by Brahe. The following year, Brahe published his observations in a text titled is De nova et nullius ævi memoria prius visa stella (Concerning the new, and Never Before Seen in the Memory of Anyone, Star). Many commentaries refer to this 1573 text as De stella nova (Concerning the New Star), but this is not Brahe’s original title and the phrase stella nova does not appear in Brahe’s 1573 text.

But as a coda to Brahe’s text, the 1573 publication includes a poem by Brahe’s friend Anders Sørensen Vedel that does use the phrase:

IN MATHEMATICAM
NOVAE STELLAE CONTEMPLATI
onem, factam a Iuuene Nobilium Doctissimo & Doctorum Nobilissimo, Thycone Brahe Otthonide.

Coellorum illustre augmentum, NOVA STELLA, quid affert?
[…]
Exite, exite, Aegyptum, Babylona, Sodmam;
Promittat CANAAN, haec noua Stella, nouam.

(WITH MATHEMATICS
NEW STARS OBSERVED
One, made by the Younger of the Most Noble Scholars and the Most Noble of Doctors, Tycho Brahe.

The glorious increase of the heavens, the NEW STAR, what does it bring?
[…]
Escape, escape, Egypt, Babylon, Sodom;
It promises CANAAN, this new Star, a new one.)

Brahe, however, would pen another treatise on the celestial event, which would be posthumously published in 1602 under the title De stella nova, as the first volume (actually published second) of his Astronomiae instauratae progymnasmata, and Brahe does use the phrase stella nova in this later text.

So while Brahe did not coin the phrase, at least in publication, the association of stella nova with him is appropriate.

By the early nineteenth century, astronomers writing in English would be using nova to designate observations of a previously unrecorded celestial object, not limited to exploding stars. Beginning in 1824, astronomers John Herschel, the son of astronomer William Herschel, and James South would start using the designation nova in their observations published in the Philosophical Transactions of the Royal Society of London.

And we see the noun nova applied to exploding stars by the end of that century. An article in the St. Louis Republic of 17 January 1899 that includes this description of looking through the thirty-six-inch refractor telescope at Lick Observatory in California:

The nebula in Orion was another object of great interest, but it baffles all description. The six stars of the Trapezium were separated, and the “Nova,” Alvan Clark’s star, was barely visible.

Astronomers Walter Baade and Fritz Zwicky coined the term supernova in lectures at Caltech in 1931. Zwicky would go on to use super-novae at a meeting of the American Physical Society in December 1933, and this use would be picked up by newspapers. From an International News Service article of 9 December 1933:

Strange temporary stars known as “Super-Novae,” composed entirely of neutrons occur in the earth’s star system about once every 1,000 years, producing the cosmic rays, he said. The stars are seen only when they explode, Dr. Zwicky declared.

The phrase “earth’s star system” probably refers to our galaxy, the Milky Way. And astronomers now estimate that a supernova appears in our galaxy every century or so. We haven’t seen one in our galaxy since 1604, which means either that we’re overdue for one or that others have occurred on the other side of the galactic center from Earth, where they have been obscured from our view by intervening dust.

Astronomer Knut Lundmark was another early user of the term supernova and may have independently coined it. He used it in an article written in 1932 and published the following year.

Earlier terms to describe the phenomenon were giant nova, exceptional nova, and the German Hauptnova (main nova). But these did not catch on.

The verb phrases to go nova and to go supernova have their origins in science fiction. In the February 1942 issue of Astounding Science Fiction, editor John W. Campbell wrote:

We’ve considered what might happen if Sol itself went nova. If it should go supernova, no worse could happen; Earth and all life on it would be fused and volatilized in either case.

But there is a very different kind of nova with a very different origin. Nova, a description and term for smoked salmon, often in the form nova lox, appears by 1955. This sense is a clipping of Nova Scotia, through which much of the product was once imported into the United States and assumed to be its origin.

Sources:

Advertisement. Evening Star (Washington, DC), 30 November 1955, A-44/1. Readex: America’s Historical Newspapers.

Brahe, Tycho. Astronomiae instauratæ progymnasmata. Uraniborg, Denmark: 1602. ProQuest Early European Books.

Campbell, John W. “Supernova Centaurus.” Astounding Science Fiction, 28.6, February 1942, n.p. Archive.org.

Herschel, John Frederick and James South. “Observations of the Apparent Distances and Positions of 380 Double and Triple Stars, Made in the Years 1821, 1822, and 1823” (15 January 1824). Philosophical Transactions of the Royal Society of London, part 3. London: W. Nicol, 1824, 82. Gale Primary Sources: Nineteenth Century Collections Online.

Historical Dictionary of Science Fiction, 11 Marcy 2021, s.v. nova, n.

International News Service. “Star Explosions Form Cosmic Rays, Scientist Asserts.” Denver Post (Colorado), 9 December 1933, 6/1. Readex: America’s Historical Newspapers.

Osterbrock, D. E. “Who Really Coined the Word Supernova? Who First Predicted Neutron Stars?” (conference presentation). 199th Annual Meeting of the American Astronomical Society, 6–10 January 2002. Bulletin of the American Astronomical Society, 33, 1330–31. SAO/NASA Astrophysics Data System (ADS).

Oxford English Dictionary, third edition, December 2003, s.v. nova, n.1, nova, n.2; June 2012, s.v. supernova, n.

Vedel, Anders Sørensen (Andreas Velleius). “In mathematicam novae stellae contemplati.” In Brahe, Tycho. De nova et nullius ævi memoria prius visa stella. Copenhagen: 1573. ProQuest: Early European Books.

“Vulcan No Myth. That Intermercurial Planet Seen by Prof. Pritchett.” St. Louis Republic (Missouri), 17 January 1899, 3/3–4. Readex: America’s Historical Newspapers.

Photo credit: David Wilton, 2023, licensable under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.