So you wanna know how the world will end? Fire? Ice? Fire and ice? I won't reveal any secrets, but I do have permission from the publisher to post an excerpt from the introduction to Death from the Skies! Enjoy.

Death from the Skies! Philip Plait, PhD Viking Press, 2008 Introduction (excerpt) The Universe is trying to kill you. It’s nothing personal. It’s trying to kill me too. It’s trying to kill everybody. And it doesn’t even have to try very hard. The Universe is an incredibly hostile place for life. Virtually all of it is a vacuum, so that’s bad right from the start. Of the extremely few places that aren’t hard vacuum, most are too hot for chemical reactions to do very well – molecules get blasted apart before they can even properly form. Of the places that aren’t too hot, most are too cold – reactions happen too slowly to get interesting things to occur in the first place. And of the very few places that aren’t in vacuum, too hot, or too cold – and we only really know of one: Earth – there are all manners of dangers lurking about. Volcanoes blast megatons of noxious chemicals into the air, spew lava for miles, and cause vast earthquakes. Tsunamis rewrite huge sections of coastlines. Ice ages come and go, mountains pop up and change the global weather system, whole continents get subducted into the glowing rock of the mantle. And those are just the local problems. Earth still sits in the incredibly hostile environment of space, and all kinds of disasters might befall us from there – literally. But then, that’s what this whole book is about. The Universe is a violent place. Stars explode. Stars like the Sun can die in milder events, but die just the same. Whole galaxies collide, igniting fireworks on a cosmic scale. Asteroids impact other planets; could they hit us? When we launched telescopes into space, we equipped them with cameras that could detect ultraviolet light, X-rays, super high-energy gamma rays. We saw a Universe that seemed actively trying to destroy us. Exploding stars are phenomenally dangerous, blasting out vast amounts of killing force and energy. Black holes are everywhere, lurking throughout the galaxy, devouring anything that wanders too close. Flashes of high-energy light from distant points in the Universe whisper of powers terrible and gross, enough to fry entire solar systems that get in the way. The Earth seemed to be the center of the Universe for much of mankind’s history. Now, however, the Earth seems fragile and impossibly small, a remote speck of dust lost in a Universe of frightening size and age. In reality, the Universe cares not at all if we live or die. If a human were magically transported to any random spot in the cosmos, within seconds we’d die 99.999999999999999% of the time. At best. Yet, despite all that (and quite a bit more still unsaid), here we are. Billions of years in, countless times around the Sun, sitting at the crosshairs of dozens of cosmic weapons… our planet endures. Life not only survives, it thrives. Numerous setbacks have occurred, for sure, but life itself continues on. As small and fragile and soft as humans are, we’ve managed so far. Of course, we haven’t yet seen everything the Universe can unleash on us. A single asteroid impact could take out half of humanity without even breaking a sweat. A solar flare could wipe out our economy in seconds. And a nearby gamma-ray burst… well, that’s bad too. Very bad. I love astronomy. I’ve devoted my entire life to it, to telling others about it, to writing about it. Astronomy is awe inspiring, it’s beautiful, it provides philosophical perspective and holds the secret answers to so many of our most profound questions. And I have no doubt whatsoever that astronomical events can kill us. In some cases, our study of astronomy can actually save us. In other cases it provides us with information about what might kill us, though unfortunately without giving us any ideas of how to stop it. And in many of those cases, there isn’t much we could do anyway. In this book, I won’t hold back. The reality of a nearby gamma-ray burst puts the sweatiest fundamentalist religion’s Armageddon prose to shame, dwarfing it to mundanity. I will go over, in loving detail, the Earth’s atmosphere ripped away, the oceans boiled, and all life sterilized down to the base of the crust. But during all that, I will remind you that there is no star nearby capable of creating such a burst; and even if there were, the odds of it going off any time soon are tiny; and even if it did, the odds of it being aimed our way are tinier yet. But it’s still fun to think about “What if…?” While you’re reading this book, you may feel like you’re watching a horror movie at the theater: it’s fun, jolting, and maybe even terrifying. During the scary parts you may want to turn away, or hide your eyes, or spill your popcorn, but I’ll make sure the actual facts of the case are there to calm you down a bit after. Of course (he says, chuckling low and with evil intent), there is a big difference: eventually the movie is over, you leave the theater, and laugh at the scary ride. You can’t do that in the real world. There are dangers out there, and we can’t avert our eyes from them. But as you read this book (hopefully with your eyes open) you’ll learn just what the dangers are, and more importantly what they aren’t. What horror movie is still scary once the lights are on? And you always have to keep in mind that we’re still here. The Universe is a dangerous place, but again, we’ve gotten this far. We may just make it a while longer. Or we may not. I have to be honest. The Universe is vast beyond imagining, and wields mighty forces. For nearly all the events depicted here, it’s not a matter of if, it’s a matter of when.