Skeptophilia (skep-to-fil-i-a) (n.) - the love of logical thought, skepticism, and thinking critically. Being an exploration of the applications of skeptical thinking to the world at large, with periodic excursions into linguistics, music, politics, cryptozoology, and why people keep seeing the face of Jesus on grilled cheese sandwiches.

Tuesday, June 6, 2023

Everything evaporates

In the episode of Star Trek: The Original Series called "Metamorphosis," the crew of the Enterprise encounters a man who has been kept alive and healthy for centuries by an entity he calls "the Companion."  I don't honestly remember it all that well -- it was kind of the usual Star Trek fare, as I recall -- but one line has stuck in my head all these years since I saw it: "Immortality consists largely of boredom."

I remember thinking as a kid what a bizarre statement that was.  Given the choice, who wouldn't want to live forever?  And, on the bigger scale, who wouldn't want the universe to exist for eternity?

When I was in high school, though, I started to run into some disquieting scientific ideas that made me realize what a pipe dream this was.  The Second Law of Thermodynamics -- that over time, all closed systems devolve toward chaos.  The fact that even the stars have births, lives... and deaths.  The three possibilities of the ultimate fate of the universe -- a collapse back into a singularity, a "flat universe" that slows its expansion but never quite gets to zero, and an accelerating universe that eventually speeds up until spacetime itself gets pulled apart.

None of which would be survivable by any life as we know it.

It all seemed so... bleak.  I remember rooting for the collapse ("Big Crunch") model, because some scientists thought this might result in an oscillating universe, one where death was followed by rebirth, a new Big Bang that would reset everything and start over.  It somehow seemed preferable to the clock simply winding down and eventually stopping.  But even that hope was dashed by the cosmologists; from the data we have, it appears either the universe is flat (the middle scenario) or hyperbolic (the third scenario).  

So it looks like the cosmos has a finite lifespan.  (If you've got a half-hour to have your mind blown, watch the wonderful YouTube video "The Timeline of the Universe" -- which takes us from now to the end, at least as far as current cosmology understands things.)

And a new piece of research has found that even the objects in that expanding, cooling universe aren't immortal.  Working at the Radboud University of Nijmegen, theoretical physicists have found that the phenomenon of Hawking radiation doesn't just apply to black holes -- it applies to everything.

In other words, everything eventually will evaporate.

[Image is in the Public Domain courtesy of NASA]

You probably know that empty space isn't really empty; it's filled with a seething foam of virtual particles that pop into existence in pairs (one matter particle and one antimatter particle) and, almost always, immediately mutually annihilate.  The overall result is nothing that generally impacts us on the macroscopic scale, since the lifetimes of these virtual pairs is measured in nanoseconds.  (It does contribute to the overall mass-energy density of empty space, however, something called the Casimir effect, which has been experimentally measured and agrees with the theoretical prediction perfectly -- so as bizarre as they sound, virtual particles are a real phenomenon.)

But there's more to it than this, and the key is the word "almost" in "almost always immediately mutually annihilate."  When the virtual pair is produced near the event horizon of a black hole, sometimes one of the particles gets trapped inside the event horizon, and the other escapes, radiating away into space.  This mass and energy is lost to the black hole, so it shrinks a bit -- and over large amounts of time, the black hole itself will evaporate away.

That's the Hawking radiation.  But what the current research showed is that this evaporation happens to everything -- not just black holes.

"[This research] means that objects without an event horizon, such as the remnants of dead stars and other large objects in the universe, also have this sort of radiation," said Heino Falcke, who co-authored the paper.  "And, after a very long period, that would lead to everything in the universe eventually evaporating, just like black holes.  This changes not only our understanding of Hawking radiation but also our view of the universe and its future."

So I guess the band Kansas might want to reconsider their lyric, "Nothing lasts forever but the Earth and sky."

The whole thing bothers me less now than it would have when I was younger.  It's not that I'm fond of the idea of death, mind you; I'm not ready to check out any time soon.  It's more that I've accepted its inevitability.  It's why the wonderful television series The Good Place was so incredibly poignant.  The main characters finally come to understand that maybe an eternity in the Good Place (heaven) isn't all it's cracked up to be, and that our appreciation of the beauty of the universe and what life has to offer comes from the fact that it is finite.  

But it should definitely focus our minds and hearts on appreciating what we have now.  I'll end with a quote from a different Star Trek episode, which (in my opinion) is the best one in the entire franchise: the Star Trek: The Next Generation episode "The Inner Light."

"Seize the time, Maribol.  Live now.  Make now always the most precious time.  Now will never come again."


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