Trying to find title of book - Scifi - Wormhole with time distortion

Question

The story was something along the lines of a wormhole was found and a "ship" or party was sent through, communication was lost a couple of weeks/months later. A second ship/party is sent and the book follows the findings of the 2nd party member who survived a "crash".

There is a fully populated planet with several different class of people who provide a certain functions to keep the planet/population running.

It ends up that the classes are generations later of the 1st ship crew who each had specific functions when they landed, however due to the time distortion of the wormhole 1000 of years past in the year following the first ship crashing.

Answer 1

This is Stephen Lawhead's two-book Empyrion cycle.

The Cynetics Corporation discovers a wormhole near Earth, and sends a colony ship through it. Shortly after, they send another ship through, carrying Orion Treet, a historian, to document the colony's growth. However, passing through the wormhole Treet's ship experiences a time dilation effect, meaning that when he reaches the colony of Empyrion he is in the future. (Quite how far forward he travels is never made clear IIRC, but I seem to think it's at least 1 000 years). The colony, Empyrion, has developed into a huge city, and the descendants of the colonists have evolved a caste system based on their original functions e.g. power generation, waste disposal, artists.