Doesn't ring a bell whatsoever.  The Gathering, as Bob seem to have described it, was a period of great change and potential, the degree of which hasn't been seen for a very long time--i remember something about some "millions" of years. 

But it wasn't attributed to anything "physical".  Just a sort of great cycle with many alignment points so to speak.

  And yes, many other Consciousnesses from many other systems were said to be interested in observing this period or cycle, presumably to see how humans will handle it.  I believe Bob or his guidance specifically said something about great crisis or potential.