extragalactic

American  

[ek-struh-guh-lak-tik] / ˌɛk strə gəˈlæk tɪk /

adjective

1. outside the Milky Way system.

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extragalactic British  

/ ˌɛkstrəɡəˈlæktɪk /

adjective

1. occurring or existing beyond the Galaxy

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Etymology

Origin of extragalactic

First recorded in 1850–55; extra- + galactic

Example Sentences

The research, published today in Nature Astronomy, introduces a new way to study how distant galaxies develop and establishes an emerging field known as "extragalactic archaeology."

From Science Daily • Mar. 23, 2026

Last year, IceCube physicists reported 79 neutrinos coming from the heart of a nearby galaxy called NGC 1068, the first steady source of extragalactic neutrinos pinpointed.

From Science Magazine • Jun. 21, 2023

The spacecraft could perform other transformational science, such as studying the extragalactic background light, the collective cosmic glow from all luminous objects in the observable universe.

From Scientific American • Jan. 6, 2022

As gamma rays travel through space, they can collide with photons in the extragalactic background, producing pairs of electrons and losing a bit of energy in the process.

From New York Times • Dec. 3, 2018

At such a rate, we will reach it in ten billion years, and extragalactic astronomy will then be a great deal easier.

From "Cosmos" by Carl Sagan