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>
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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>
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Wiktionary's word of the day:
kitchendom:
(dated) The domain of the kitchen or people who work there.
<https://en.wiktionary.org/wiki/kitchendom>
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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>