spiral arm

American  

noun

Astronomy.

1. any of the elongated and curved spiral sections that are connected to the center of a spiral galaxy.

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Etymology

Origin of spiral arm

First recorded in 1910–15

Example Sentences

It also could hold clues to why the Milky Way has its spiral arm.

From Salon • Nov. 21, 2023

This discovery also connects spiral arm instabilities to the episodic growth bursts - a key factor for how high-mass stars form.

From Space Scoop • Mar. 29, 2023

But that usually requires the supermassive black hole in the center of a galaxy, and the Cow is situated in its galaxy’s spiral arm.

From Science Magazine • Jan. 11, 2019

The Sun is located in the Orion Spur, which is a minor spiral arm located between two other arms.

From Textbooks • Oct. 13, 2016

When the Sun passes through a spiral arm it is more likely than it is at present to enter into gaseous nebulae and interstellar dust clouds and to encounter objects of substellar mass.

From "Cosmos" by Carl Sagan