Supernovae might produce gravitational waves, though thus far, gravitational waves have been detected only from the mergers of black holes and neutron stars. Etymology The word supernova has the plural form supernovae or supernovas, and is often abbreviated as "SN" or "SNe". It is derived from the word nova, in Latin meaning "new", which refers to what appears to be a temporary new bright star. Adding the prefix "super-" distinguishes supernovae from ordinary novae, which are far less luminous. The word supernova was coined by Walter Baade and Fritz Zwicky, who began using it in astrophysics lectures in 1931. Its first use in a journal article came the following year, in a publication by Knut Lundmark, who may have coined it independently. Observation history Compared to a star's entire history, the visual appearance of a supernova is very brief, sometimes spanning several months, so that the chances of observing one with the naked eye is roughly once in a lifetime. Only a tiny fraction of the 100 billion stars in a typical galaxy have the capacity to become a supernova, being restricted to those having high mass and rare kinds of binary stars containing white dwarfs. Early discoveries The earliest possible recorded supernova, known as HB9, could have been viewed by unknown prehistoric people of the Indian subcontinent, then recorded on a rock carving found in Burzahama region in Kashmir, dated to . Later, SN 185 was documented by Chinese astronomers in 185 AD. The brightest recorded supernova was SN 1006, which occurred in 1006 AD in the constellation of Lupus. This event was described by observers across China, Japan, Iraq, Egypt, and Europe. The widely observed supernova SN 1054 produced the Crab Nebula. Supernovae SN 1572 and SN 1604, the latest to be observed with the naked eye in the Milky Way galaxy, had a notable influence on the development of astronomy in Europe because they were used to argue against the Aristotelian idea that the universe beyond the Moon and planets was static and unchanging. Johannes Kepler began observing SN 1604 at its peak on 17 October 1604, and continued to make estimates of its brightness until it faded from naked eye view a year later. It was the second supernova to be observed in a generation, after SN 1572 seen by Tycho Brahe in Cassiopeia. There is some evidence that the youngest galactic supernova, G1.9+0.3, occurred in