Natural History: Orion and Plieades

"Can you bind the chains of the Pleiades, or loose the cords of Orion?” Job 38:31 (NIV)

An awe-inspiring piece of Bible trivia I picked up several years ago about this scripture was that whilst the book of Job is the earliest books of the Bible written - apparently it was only last century, in this advanced age it was discovered that within:

Orion – the cluster of stars are bound together so strongly by the gravitational forces that they remain locked in relative position to one another.
Plieades – the cluster of stars are held together but the gravitational forces are such that the stars are continually drifting away from one another but at a distance so small that it cannot be noticed without the aid of modern astronomical equipment.

I’d like to validate this with a secular source as this insight came from “Answers In Genesis” – but if it is true - it is wonderfully mysterious how the writers of the earliest book of the Bible could possibly have of know this…

Who can tamper with the gravitational forces that hold star clusters together bar God alone?