supernova

[soo-per-noh-vuh]

noun

Astronomy.

plural

supernovas, supernovae 

1. the explosion of a star, possibly caused by gravitational collapse, during which the star's luminosity increases by as much as 20 magnitudes and most of the star's mass is blown away at very high velocity, sometimes leaving behind an extremely dense core.

2. the star undergoing such an explosion.

supernova

/ ˌsuːpəˈnəʊvə /

noun

1. a star that explodes catastrophically owing to either instabilities following the exhaustion of its nuclear fuel or gravitational collapse following the accretion of matter from an orbiting companion star, becoming for a few days up to one hundred million times brighter than the sun. The expanding shell of debris (the supernova remnant ) creates a nebula that radiates radio waves, X-rays, and light, for hundreds or thousands of years Compare nova

supernova

plural

supernovae 

1. A massive star that undergoes a sudden, extreme increase in brightness across the electromagnetic spectrum, followed by a more gradual decrease lasting from several days to several months. Supernovae occur when a supergiant star collapses suddenly at the end of its life, condensing its core material into an extremely compact mass that then undergoes a slight rebound. The resulting shock wave sends all matter surrounding the core flying into space, leaving a neutron star or black hole at the site of the core's collapse. Supernovae may also occur when a white dwarf accretes material from a companion red giant star, resulting in an increase in mass that eventually triggers carbon fusion in the core of the white dwarf; the sudden increase in available fuel causes energy to be released in a violent explosion. In both cases the shock waves induce further fusion in the matter surrounding the collapsed core; the many elements resulting from this fusion and from the various other stages of nucleosynthesis over the lifetime of the star are scattered into space. These elements serve as the material from which new stellar and planetary systems are formed; in fact, every heavy element found on Earth is thought to have been the product of supernovae explosions. The last supernova to be observed in the Milky Way was seen in 1604 by Johannes Kepler and was used by Galileo, at his trial, as evidence against the presupposition that the universe never changes.

2. Compare nova

supernova

1. A large star in its death throes that suddenly explodes, increasing many thousands of times in brightness.

In 1987, a supernova was sighted near the Milky Way galaxy. This supernova provided astronomers with a unique opportunity to test the theories of the structure of stars.

Most heavy elements are created by nuclear reactions in supernovas and then returned to space.

Word History and Origins

Origin of supernova¹

First recorded in 1925–30; super- + nova

Example Sentences

When you imagine an explosion in space, a supernova is usually what first comes to mind.

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At that spot, they found the shining remains of a supernova.

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They say that this White Dwarf wrapped itself in a blanket of stolen gas that caught alight quickly, sending a pulse of pressure into the core of the star that ignited the supernova.

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Such simulations could shed light on major open questions in physics, including the imbalance of matter and antimatter, the creation of heavy elements inside supernovae, and the behavior of matter at ultra-high densities.

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Scientists have long hoped to observe this initial moment because it helps answer key questions about how massive stars end their lives as supernovae.

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Related Words

• void