Mortality's been on my mind more lately, for really obvious reasons: A very close family friend died suddenly in December, a former girlfriend of mine died suddenly a few weeks ago, and there has been a spate of two-degrees-of-separation deaths as well, i.e. not people we knew, but people we knew knew. That'll sure make you think about death a lot!
It still doesn't hugely bother me, and I mostly stand by what I wrote about the topic back in January 2010. The thought of oblivion is a little bit more unnerving now that it's more viscerally "real" to me, but not that much more unnerving. What's actually been troubling me more than the idea of my own eventual annihilation has been proton decay and its implications about the fate of the universe. I'm finding the idea that someday every particle in the universe will have disintegrated, even if it's an absolutely inconceivable 1090-odd years in the future, to be really troubling and bleak.
So then this morning on the drive to work I was thinking about cosmic voids (yes, really) and for a moment I had that same feeling of an incomprehensible magnitude of bleak nothingness -- though not quite as powerfully as when contemplating the eventual breakdown of all the protons in the universe. It hit me that, depending upon how we view the relationship between space and time, as well as how much stock we put in the concept of the present, they could be no different!
Nobody really quite knows what to make of time. I tried reading The End of Time by Julian Barbour, which proposes a radical reimagining of how we perceive time in relation to physical reality, but I only made it about 2/3 of the way through before the heady math and geometry was just too much for me. In any case, where I'm leading is that one way of viewing the universe is as a static 4- (or more-) dimensional object. There's no particular present, just points in spacetime. Of course there are many different ideas on how we ought to interpret time in relation to physical reality, but this is one of them, and based on our limited knowledge at this point in history, it could be valid.
If we look at it that way, then there is little practical difference between the incomprehensible emptiness of cosmic voids in the spatial domain vs. the incomprehensible emptiness of a dead universe in the temporal domain. (Depending on the spatial geometry of the universe, there could be one important difference, in that if the universe is finite but unbounded for example, there's no spatial direction you could go in where you would encounter unending emptiness, but there is a temporal direction where you can... but I'm not sure how important this is to my point here.) So when we stare into the temporal abyss, when we contemplate the eternal death of the universe, it ought to be no more existentially disturbing than when we contemplate the spatial abyss of these incomprehensibly large voids.
Which is to say, it's still pretty freakin' disturbing, but perhaps more manageable. Voids are still one of the bleakest things I've ever heard of.