Has anyone studied the very centre? It looks to me like it might fit a flower ship, like a control centre or a star trek like "saucer section".
Maybe the flower ship visits to the sites are checking progress.
I did a fly-over of a US and to me it looks like there is a doorway at the bottom of the centre structure.
Similar to the inter-leaved doorway at the entrances.
Here is the video I captured: -
[video=youtube_share;DKOR8BnPKZU]https://youtu.be/DKOR8BnPKZU[/video]
So looks to me like something is likely to emerge at some point after the 2.4 update.
With regards to the structures growing I must admit I thought the barnacle sites were growing (more unknown organic structures) but I have no hard evidence.
It's all very exciting and kind of scary at the same time.
When it kicks off I'll be there...hiding in the nearest nebula!