In tweet fired out on Thursday, Gross said the bond market — and its $10 trillion of negative-yielding bonds — is, "a supernova that will explode one day."

Now, for regular readers of Gross' monthly commentary his apocalyptic views on the global economy aren't exactly new, though this supernova imagery is particularly vivid. 

Earlier this month, for example, Gross said the last 40 years of investing history — a period that has seen both stocks and bonds rally — are a 'black swan' event that won't be repeated again. 

And elsewhere in space-related doom metaphors, Gross earlier this year said capitalism is dying and will blow up, sun-like, before the actual sun blows up (we've got about 5 billion years for that).