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AR CLUSTERS
M13 globular cluster Image: Mike Greenham There are two types of star cluster, open and globular. Open clusters are more loosely clustered stars and usually contain fewer stars than their globular counterparts. Over time giant molecular clouds can have gravitational influence over the cluster. Generally the stars in these type of clusters are younf stars.
Globular Clusters These are large groupings of stars, they appear spherical. Their numbers can range from 10,000 to several Millions in a 10 to 30 million light year area. These clusters are old or older stars and may be only a few million years younger than the universe itself.
“A light-year is a unit of distance. It is the distance that light can travel in one year. Light moves at a velocity of about 300,000 kilometers (km) each second. So in one year, it can travel about 10 trillion km. More p recisely, one lightyear is equal to 9,500,000,000,000 M80 GLOBULAR CLUSTER Image: Wikipedia
kilometres�. (NASA)
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