supernova

American  

[soo-per-noh-vuh] / ˌsu pərˈnoʊ və /

noun

Astronomy.

• supernovas,
  plural
• supernovae
  plural

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.

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supernova British  

/ 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

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supernova Scientific  

/ so̅o̅′pər-nō′və /

• supernovae
  plural

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

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supernova Cultural  

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

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Discover More

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.

Other Word Forms

Noun Inflected Forms

• supernovae
  plural
• supernovas
  plural

Etymology

Origin of supernova

First recorded in 1925–30; super- + nova

Explanation

Supernova is an astronomical term for a star that explodes like crazy. When a star turns into a supernova, it becomes extremely bright. Supernova sounds like a superhero, but it refers to the super explosion of a star. A nova is also the explosion of a star, but a supernova has more energy. A supernova happens when a star becomes bright, bursts, and its matter is scattered in all directions, with light and radiation shooting out. Some say our sun will turn into a supernova someday, which would destroy all life on Earth. Don’t worry, that’s a long way off.

Example Sentences

See Examples For:

supernova supernovae supernovas

One especially energetic kind of Pop III supernova, called a pair-instability supernova, can eject more than 100 times the Sun's mass in heavy elements during a single explosion.

From Science Daily ● Aug. 31, 2026

If that were true, astronomers could have been misreading the supernova data and incorrectly concluding that cosmic expansion was speeding up when it was actually slowing.

From Science Daily ● Aug. 29, 2026

Very massive stars can end their lives in supernova explosions, but such events are relatively uncommon.

From Science Daily ● Aug. 12, 2026

When a massive star explodes as a supernova, for example, the blast can launch the stellar remnant in one direction at high speed.

From Science Daily ● Jul. 21, 2026

There’s only so much being invisible you can take before you just want to go supernova so no one can ignore you anymore.

From "From Twinkle, with Love" by Sandhya Menon

Type Ia supernovae are extremely bright explosions that are generally believed to occur when a white dwarf becomes unstable and undergoes a runaway thermonuclear reaction.

From Science Daily ● Aug. 1, 2026

These reactions play a central role in producing heavy elements during extreme cosmic events, including supernovae and neutron star mergers.

From Science Daily ● Jul. 31, 2026

"Covalently bonded carbon and hydrogen in comet and asteroid material are believed to have formed in the outer envelopes of stars, in high-energy events like supernovae, and in interstellar environments," Ms. Losurdo said.

From Science Daily ● Jul. 19, 2026

Instead of fading smoothly, as most supernovae do, its brightness rose and fell repeatedly.

From Science Daily ● Jul. 6, 2026

But a rousing of the stellar fires in N49 is a simpler hypothesis: we are sure there are such things as supernovae.

From "Cosmos" by Carl Sagan

"Our prediction is that we'll see a lot more galactic cosmic radiation... which is from supernovas and is everywhere," versus radiation coming from the Sun, he said.

From Barron's ● Apr. 10, 2026

Instead of treating these stellar explosions as having one standard brightness, they adjusted for the ages of the galaxies they came from and worked out how bright the supernovas really were.

From BBC ● Dec. 27, 2025

Neutron stars are the smallest, most dense stars known to exist and are formed when massive stars explode in supernovas.

From Science Daily ● Apr. 26, 2024

Ever since, neutrinos have been detected in the Sun, during supernovas and even in interactions between cosmic rays and the upper atmosphere.

From Salon ● Aug. 31, 2023

But unlike Hubble’s dim Cepheids, supernovas are visible halfway across the universe.

From "Zero: The Biography of a Dangerous Idea" by Charles Seife

Related Words

• void