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.

---

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

---

Etymology

Origin of molecular cloud

First recorded in 1970–75

Example Sentences

These stellar pairs are born together out of the same molecular cloud from a shared abundance of chemical building blocks, so astronomers would expect to find that they have nearly identical compositions and planetary systems.

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