Photon sphere

Rarity: Common

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At a glance

Class

Notion

Domain

Science and technology

In collections

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What Wikipedia says

A photon sphere, or photon ring or photon circle, arises in a neighbourhood of the event horizon of a black hole where gravity is so strong that emitted photons will not just bend around the black hole but also return to the point where they were emitted from and consequently display boomerang-like properties.

Excerpt from the Wikipedia article “Photon sphere”, under the CC BY-SA 4.0 license. Read the article on Wikipedia

Image: Hugo Spinelli, CC0, via Wikimedia Commons.