giant molecular cloud

American  

noun

1. Astronomy. a type of molecular cloud whose mass exceeds that of the Sun by 10 thousand to 10 million times and whose complex substructure includes dense molecular filaments that will most likely become stars.

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giant molecular cloud Scientific  

1. A cloud of molecular hydrogen typically located in the arm of a spiral galaxy, believed to be an area of active star formation. Protostars are located in the densest regions of such clouds.

2. See more at protostar

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Example Sentences

Suppose that, instead of being inside the Local Bubble, the Sun were deep inside a giant molecular cloud.

From Textbooks • Oct. 13, 2016

Every few hundred million years or so, the cluster may have a close encounter with a giant molecular cloud, and the gravitational force exerted by the cloud may tear the cluster apart.

From Textbooks • Oct. 13, 2016

Consider the following five kinds of objects: open cluster, giant molecular cloud, globular cluster, group of O and B stars, and planetary nebulae.

From Textbooks • Oct. 13, 2016

The cluster is probably a previously unknown giant molecular cloud, an unmapped stellar nursery filled with protostars, Wright says.

From Scientific American • Apr. 17, 2015