Open clusters become disrupted over time by the gravitational influence of giant molecular clouds as they move through the galaxy , but cluster members will continue to move in broadly the same direction through space even though they are no longer gravitationally bound ; they are then known as a stellar association , sometimes also referred to as a moving group .
They are held together by the gravitational attraction of the stars , which are related all through common origin .
They are held together by the gravitational attraction of the stars , which are related all through common origin .
Make the sentence simpler: Open clusters become disrupted over time by the gravitational influence of giant molecular clouds as they move through the galaxy , but cluster members will continue to move in broadly the same direction through space even though they are no longer gravitationally bound ; they are then known as a stellar association , sometimes also referred to as a moving group . Output: