A supernova is a powerful explosion of a star, usually a star that is unable to produce sufficient energy from nuclear fusion to counteract its own gravity. Its remnant will become a diffuse nebula, neutron star or black hole. The peak optical luminosity of a supernova can be comparable to that of an entire galaxy before fading over several weeks or months. Supernovae occur in the Milky Way on average about three times every century; the last one directly observed was Kepler's Supernova (remnant pictured) in 1604. The most recent naked-eye supernova from another galaxy was SN 1987A, the explosion of a blue supergiant star in the Large Magellanic Cloud, a satellite of the Milky Way. Supernovae can expel several solar masses of material at velocities up to several percent of the speed of light. They are a major source of cosmic rays, and also the chemical elements from oxygen to rubidium on the periodic table. White dwarfs can also produce supernovae, if they gain enough mass to trigger runaway fusion.

Read more: https://en.wikipedia.org/wiki/Supernova

_______________________________ Today's selected anniversaries:

1724:

Sie werden aus Saba alle kommen, a Bach cantata for Epiphany, was first performed in Leipzig. https://en.wikipedia.org/wiki/Sie_werden_aus_Saba_alle_kommen,_BWV_65

1912:

German geophysicist Alfred Wegener presented his theory of continental drift, the precursor of plate tectonics. https://en.wikipedia.org/wiki/Continental_drift

1953:

The inaugural Asian Socialist Conference, an organisation of socialist political parties, opened in Rangoon with 177 delegates, observers and fraternal guests. https://en.wikipedia.org/wiki/Asian_Socialist_Conference

2014:

The first episode of the documentary series Benefits Street aired on Channel 4, prompting discussion in the United Kingdom about welfare dependency. https://en.wikipedia.org/wiki/Benefits_Street

_____________________________ Wiktionary's word of the day:

kitchendom: (dated) The domain of the kitchen or people who work there. https://en.wiktionary.org/wiki/kitchendom

___________________________ Wikiquote quote of the day:

Those who stormed this Capitol and those who instigated and incited and those who called on them to do so held a dagger at the throat of America, at American democracy. They didn't come here out of patriotism or principle. They came here in rage. Not in service of America but rather in service of one man. Those who incited the mob, the real plotters who are desperate to deny the certification of this election, and defy the will of the voters. But their plot was foiled; congressmen, Democrats, Republicans stayed. Senators, representatives, staff, they finished their work the Constitution demanded. They honored their oath to defend the Constitution against all enemies, foreign and domestic. Look folks, now it's up to all of us — to We the People — to stand for the rule of law, to preserve the flame of democracy, to keep the promise of America alive.   --Joe Biden https://en.wikiquote.org/wiki/Joe_Biden