When an Asteroid Hits a Planet

There's going to be some spoilers for Lords of Kobol - Book Two: Descent, so if you want to remain completely virginal, please stop reading now.

The spoilers in question, though, are not major and don't really compromise any enjoyment of the story.  (In my opinion.)

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I'm going to start with a quote from Gaius Baltar and the fourth season episode "The Hub":

"Pythia talks about a flood that wiped out most of humanity. Nobody blames the flood. The flood is a force of nature. Through the flood, mankind is rejuvenated -- born again."

And with that line, we discover that Kobol's history is not terribly different from our own.  There are dozens of ancient civilizations with flood myths so why should Kobol be any different?

I decided early on that I wanted the gods to descend to Kobol in a very dramatic fashion.  This, coupled with the need for a flood myth, gave me plenty of options.  The vast majority of flood myths on Earth involve some level of divine retribution so I thought it would be interesting to make it so that the gods try to save mankind from the flood instead of the other way 'round.  (Plus, what better way to endear yourselves to potential followers?)

Scientifically speaking, we know that there has been no singular worldwide deluge on Earth and I had no desire to craft some sort of tale like that here.  In fact, many scholars believe that ancient flood myths are derived from local events that cause widespread damage and in the telling of the tale, the speaker believes that the whole world was affected.  So why not have a catastrophic local event in which the Lords save many people?

Without spoiling more stuff, let me just say there is a gathering of some 30,000+ people near the base of Mount Olympus, before the gods have descended and revealed themselves.  The Lords discover that an asteroid will soon crash into Kobol and they feel compelled to help as many people as they can.

Now.  An asteroid impact in the nearby ocean sounds awesome, but I wanted to get the science as close to right as I could.  What, oh, what can I do?

I found this great website: Impact: Earth!

Put together by the folks at Purdue University (and thanks to Jay Melosh for answering a few of my questions), it's a fun, Flash-based site where you just punch in a few numbers, play with some variables and see what happens when an asteroid hits the planet.

I knew what I wanted to have happen: asteroid hits offshore, an impact wave (or tsunami) washes over the coast, into the valley and wipes away most of the settlement that the gods couldn't save.  So, it was a matter of playing with the variables on the site.  But, there were loads of other little details I didn't think about.  Details that make that part of the book that much richer.

There's the sight of the asteroid, breaking up as it crosses the sky and disappearing over the horizon.  The flash and with that flash, searing radiation that can cause first-degree burns for almost three minutes.  While your skin is burning, the earthquake begins (about a 7.5 magnitude).  Three minutes later, a fine dust ejecta, like gray snow, drifts and blows onto the village.  Eleven minutes after impact, the sound of the asteroid entering the atmosphere and impacting finally reaches your ears.  Twelve minutes after impact, there's the airblast, a rush of 90mph wind that knocks down trees and destroys what huts weren't already trashed by the quake.  As if all of that wasn't bad enough, the tsunami comes about half an hour later with waves higher than one hundred feet.

You see?  All I wanted was an asteroid and sea surge.  Instead I get a treasure trove of detail that I can use to flesh out what could have been a simple action beat.

If you want to plug in the numbers of my asteroid, here you go: 1,000 m in diameter; density of 3,000 kg/m^3; angle 50 degrees; impact velocity of 18 km/s; distance from impact 243 km; impact in water of depth 1000 m.  You may not end up with exactly the same thing I used in the book, but it's close enough.

In the end, it's an awesome scene that does more than have a cool bit of action.  It sets up a LOT as far as the relationship between the gods and mankind.

If you want to know more, download and read the book.