Complex sentence: Some time after their arrival, the colonists discovered that "metaphasic radiation" from the Briar Patch has become concentrated in the planet's rings, continually rejuvenating their genetic structure; unbeknownst to the outside universe, the Ba'ku planet is effectively a fountain of youth.
Split into simpler sentences: Some time after their arrival, the colonists discovered that "metaphasic radiation" from the Briar Patch, concentrated in the planet's rings, continually rejuvenated their genetic structure. Unbeknownst to the outside universe, the Ba'ku planet was effectively a fountain of youth.