So I had an idea earlier today and was wondering. Most sources you consult about the supposed "vacuum metastability event" say that the bubble would begin expanding at NEARLY the speed of light, not exactly the speed of light. How much slower would it really be? Would it give us enough time to see it coming or would it still happen so fast we'd be annihilated instantly?
For example, if it was slowed to 99%, 98%, 97% etc., would we be able to see the stars going out in the night sky like so many popular sci fi flicks? How long could we ever have to conceivably prepare for a vacuum metastability event before it arrives? Days? Months? Years?
If anyone knows anything about this, it'd be really helpful.