Thursday, June 25, 2009
Death From The Skies! by Phil Plait
I've always found the end of the world fascinating. So many cultures have put together their own ideas of how the world will end, from the Norse Ragnarök to the Christian apocalypse to the Hindu cycle of creation and destruction. We live in a world that was, for a long time, unpredictable to us and on many occasions seemed to be outwardly hostile. Our ancestors faced floods and earthquakes and disease, with no idea of where these things came from, why they happened or how to stop them. And so they made myths and stories to explain the dangerous world in which they lived. From that, they extrapolated - if the world is this dangerous now, how dangerous could it be if it really tried? And so came our myths of a world that not only succeeds in hurting us, but in wiping us out altogether.
Even in the modern age we have our myths. Books, television, and movies all use the end of the world (or end of a world) to tell stories - usually about the resilience of mankind and our ability to pick ourselves up, dust ourselves off, and rebuild human society, hopefully for the better. As good as this is for fiction, there are two problems when we try to apply these myths and stories to the real world: the world will end, one way or another, and no amount of heroics, cleverness or pluck will save us. Not in the long term, anyway.
Science has accomplished what religion and fiction could not - it has seen the future and can make fairly accurate prophecies about how this world, and our civilization upon it, will die. Renowned astronomer Phil Plait is your prophet for this trip into all the ways the world will end....
In this book, Plait looks at nine possibilities for the end of the world as we know it. In order, they are:
Death by Impact
Death from the Sun
Death by Supernova
Death by Gamma Ray Burst
Death by Black Hole
Death by Aliens
Death of the Sun
Death by Galactic Collision
Death of the Universe
In each chapter, Plait outlines the ways in which that specific event could injure or kill us, with as much science as he can comfortably put in. He explains, for example, why we can't just send Bruce Willis up to hit an incoming meteor with a nuke (it probably won't work) and why any black holes produced by the LHC won't do us any harm. He looks at how a supernova happens, what it is about a black hole that turns it into one of the deadliest weapons in the universe, and tries - very, very hard - to make the reader understand exactly how long "forever" is. (Hint: it's a lot longer than you think. Longer than that, even. Nope, keep going....)
Each chapter outlines the processes by which we could experience the destruction of our civilization or, in a few cases, the planet itself. He looks at the scientific foundations of these events, explaining in detail what it is about the sun, for example, that makes it a cauldron of chaos and torment, or why we really, really don't want to get even a smallish black hole anywhere near the planet. And I have to say, of all the unlikely ways we could be toasted, gamma ray bursts are my favorite - a deadly beam of energy from thousands of light-years away, cooking the planet all the way down through the crust and utterly devastating the planet's ecosystem so as to kill off anyone who was lucky enough to be on the other side of the world. I mean, wow. And there'd be no warning, either. By the time we knew what was happening, it'd be too late. So that chapter (with a line paying homage to Douglas Adams, even) is just mind-boggling.
Probably my favorite chapter, though, is the one about supernovas, mainly because his careful, step-by-step description of exactly how a supernova occurs made me think, "What I wouldn't give to see that in person," disregarding the fact that a) the best parts would happen way too fast for me to observe and b) it would vaporize me. Still, it's a beautiful and terrifying chain reaction, which Plait describes in fantastic detail. The other chapter that evoked the same reaction was the one on the end of the universe. Despite timelines for which the word "vast" is terribly inadequate, Plait tells us what science knows about how the universe will end - the ever-increasing expansion of spacetime, the eventual death of the stars, evaporation of galaxies, the reign of the black holes and the slow, careful deaths which even they face. It all ends in darkness, all matter gone into a few stubborn subatomic particles and the eventual collapse of the very fabric of space and time.
And as bleak and miserable is the future looks, I still thought, "I really want to see that." So if I can figure out how to live one googol years (that'd be a one with one hundred zeros after it ) and not have my very atoms decay into nothingness, then I'll be able to... um... be really, really bored, probably. Since after that, there's absolutely - literally - nothing to do. Until the universe experiences vacuum collapse, or a brane collision, possibly hitting the reset button on the cosmos and we get to do it all over again....
Most of what's in the book isn't new to me, but that's probably because I grew up reading Cosmos, and I follow countless science TV shows, podcasts and blogs (including Plait's own Bad Astronomy blog, which is well worth keeping up with, as well as his regular appearances on SETI's podcast, Are We Alone? and occasional guest appearances on The Skeptics' Guide to the Universe - both of which make for excellent listening). For people new to astronomy, though, this will be a rather dense learning experience - and reading it will be time well spent.
In addition to its user-friendly style, I really like the way it's arranged - from small-scale (relatively) to large, with "Things that are absolutely certain to happen" at the beginning and end, and with "things that probably won't happen" in the middle. And my favorite aspect of this book is that each chapter begins with a short vignette describing that particular end of the world, from the perspective of someone watching it happen. It's not something you often see in books of this nature, and I'm really glad that Plait decided to put it in there. It makes it a little less academic and abstract and more real.
For all its death and destruction, the book isn't really a downer. For one thing, while things like asteroid impacts and the death of the sun are inevitable, they don't have to be fatal, and Plait describes a few ways in which - in theory - we (or our distant, distant descendants) might be able to avert or at least mitigate these catastrophes. It's not easy, of course, but saving the world never is.
It's mainly a marvel at the forces that surround us in the universe. It's easy to forget, looking up at the sky from our brief, limited scale, that the universe isn't just some pretty lights drifting about in empty blackness. Things are exploding and dying, burning and freezing, moving quickly and slowly - the cosmos is replete with activity and danger. Most of the universe isn't just uninhabitable, it's actively hostile to life as we know it. And yet, without the black holes, the supernovas and the galactic collisions, without massive meteor impacts and breakaway comets, solar flares and deadly radiation - without all that, life probably wouldn't exist at all. So read this book, and take a moment to appreciate how lucky we are to be here at all, all things considered....
"They say that even the brightest star won't shine forever. But in fact, the brightest star would live the shortest amount of time. Feel free to extract whatever life lesson you want from that."
- Phil Plait, Death from the Skies!
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Phil Plait on Wikipedia
Bad Astronomy blog
Death from the Skies! on Wikipedia
Death from the Skies! on Amazon.com