molecular cloud

American  

[muh-lek-yuh-ler kloud] / məˈlɛk yə lər ˈklaʊd /

noun

Astronomy.

1. an interstellar cloud of gas and dust composed of hydrogen, helium, and other molecular remnants of a supernova.

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molecular cloud British  

noun

1. a cool dense interstellar region composed of a wide variety of molecules, mainly hydrogen, plus some dust, in which stars are forming

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Etymology

Origin of molecular cloud

First recorded in 1970–75

Example Sentences

The third possible explanation looks back at the beginning of the stars' formation, suggesting that the differences originate from primordial, or pre-existing, areas of nonuniformity within the molecular cloud.

From Science Daily • Apr. 29, 2024

This image, taken from Canberra, Australia, shows a dark, thick molecular cloud in the form of a wolf, known as the Wolf Nebula or Fenrir Nebula.

From BBC • Sep. 14, 2023

On the other end of the scale, we have the Orion B molecular cloud complex, a truly enormous site of active star formation that’s over a thousand light-years away and many hundreds of light-years across.

From Scientific American • Apr. 24, 2023

Protostars are very young stars that are still growing in mass via its parent molecular cloud; such objects may have yet to absorb or expel the remaining gas and dust in their planetary nebulae.

From Salon • Mar. 15, 2023

Star formation can move progressively through a molecular cloud.

From Textbooks • Oct. 13, 2016