Which adds to the other detail: the exposed aether at Mor Dhona is blue-green before the events, much like the normal aetherytes, and is a pale blue after, as if drained. Based on Atomos and concepts, one can presume that tons of aether in one spot makes them orange, and red is so much that the device ceases to function. (Sidebar: Could this be why Dalamud was capable of being unsealed?)
Based on the aftermath of Midgarsormr's apparent suicide to destroy the mothership, there was, as far as we can tell, a sudden release of aetheric energy, which also:
..summoned the Primals from slumber.
And this all happened 15 some years ago.