accretion disk

noun

variants or less commonly accretion disc

plural accretion disks also accretion discs

: a disk of usually gaseous matter surrounding a massive celestial object (such as a black hole) in which the matter gradually spirals in toward and accretes onto the object as a result of gravitational attraction

Evans' team studied a supermassive black hole with jets 800 million light-years away named 3C 33. They never found an expected X-ray pattern … which results from light reflecting off the accretion disk.

—Bill Andrews

Most other moons are either captured planetesimals, or they formed along with the planet in a common accretion disc.

—Daniel Herwartz, et al.

Examples of accretion disk in a Sentence

Recent Examples on the Web

Additional analysis showed that around 70 percent of these LRDs displayed evidence of gas swirling around 2 million miles per hour—solid indicators of accretion disks surrounding supermassive black holes. —Andrew Paul, Popular Science, 7 Aug. 2025

That matter spirals around the black hole, forming what’s called an accretion disk, and there’s so much matter that the accretion disk becomes a bottleneck. —Keith Cooper, Space.com, 1 Aug. 2025

Some hypothesize that dense material in the accretion disk may periodically clash and create shocks that produce fresh bursts of radiation. —Thomas Westerholm, MSNBC Newsweek, 25 June 2025

Typically, about half the star's matter is ejected outward while the remainder forms a glowing accretion disk—a structure made of gas, dust or other material that spirals inwards—around the black hole, briefly illuminating the cosmos in various wavelengths. —Thomas Westerholm, MSNBC Newsweek, 25 June 2025

Word History

First Known Use

1972, in the meaning defined above

Rhymes for accretion disk

• videodisc
• basilisk
• bisque
• brisk
• disc
• fisc
• fisk
• frisk
• risk
• whisk