Beware the asteroid?

It’s always fun to run across a scientist who’s fascinated by the end of the world, and Thomas A. Cahill fits the bill. He’s a particle physicist at UC Davis, best known for his work on the environmental impact of the 9/11 attacks on World Trade Center. But he’s also a science-fiction writer, and his new book Ark: Asteroid Impact (EditPros LLC, $16.95) depicts what happens when the Earth (and its people) takes a hit from an asteroid. According to Cahill, it’s a likely scenario. The latest asteroids to threaten the planet passed by the Earth last month and in December 2012—without consequence, it should be noted. Cahill talked to SN&R about dangerous space debris, climate change and the possibility of another ice age.

Should we be scared of these close calls with asteroids?

Last December 12, [2012], one went by even closer, and we didn’t know it until it passed. We had another one that went by outside the moon and was spotted very late, so it was almost missed. … What we’ve learned, in the last 20 years, is that the Earth has been bombarded regularly by asteroids. The most famous was the K-T event in the Yucatan, which some argue led to the extinction of the dinosaurs.

But you don’t study asteroids.

My field of expertise is climate change. We used to talk about nuclear winter, but it occurs to me that it’s much more likely for an asteroid to hit us and cause the sort of climate change we once believed would follow a nuclear war. So I wrote this novel with as much science as I could in it.

I use the 4179 Toutatis as the example—it’s a large asteroid that comes close to the Earth periodically, as it did last December. It’s always missed us. The scenario in my novel is that it bounces off an unknown small asteroid, which changes its course in the last day or two, and it strikes the Earth with very little notice. This is a worst-case scenario. The heroes of the book are scientists and students from a local university. They’re torn, because if they’re wrong about the asteroid, they’ll look like idiots. But if they’re right, they’ll be dead. I wanted to put myself—and the readers—in their shoes [and ask the question]: If the president came on TV tonight and said an asteroid is going to hit the Earth tomorrow, what would happen? How would people react?

What would we experience?

First, there would be tsunamis all around the Earth. This is what happened when the Yucatan asteroid hit. Second, there would be a dust cloud that would most likely cause a new ice age.

The question is: What would civilization do? Some people get lucky, that’s all. Each small group may have a shot at surviving, and those survivors will have to put together new ecosystems, new cultures. My book is pretty optimistic. The externals are terrible, but they have their wits about them.

They have to deal with 20 meters of snow covering the country from coast to coast, and with 350 million people lost. It’s massive and shocking. But it also leaves this completely new world there to be discovered, and it’s a book of discovery with as much science as I [could] get into it.

Tell me about your areas of research.

One involves global climate change and the effects of airborne particles on both the present climate and the paleoclimate. Right now, we’re studying particles in the ice core in Greenland. These wonderful ice cores in Greenland go back 100,000 years, and there’s dust in them. We’re examining that dust and comparing it to current dust to try and understand what the climate was like in the past.

What else are you working on?

I’m also working on particles in the air near highways. We’re doing a lot of work on highways. It’s not just exhaust that releases particles into the air. For instance, brake drums on cars are releasing metals like iron and copper, but in a very small particle that gets deep in your lungs and can be extremely toxic.

And you started by studying nuclear winter?

Yes, I did. But the science behind nuclear winter was not very good. It was good in that it may have helped discourage nuclear war, but in terms of the nuclear blasts, there wasn’t enough aerosol, and it didn’t last very long. It wouldn’t have caused the sort of planetary climate change that we’ve seen from other kinds of dust.

I also worked on the aerosols on the burning oil wells in Kuwait after the first Gulf War. Those aerosols didn’t cause as many problems as we thought they would, because the aerosols stayed low in the atmosphere.

Now, with an asteroid strike, the dust particles will definitely be high in the atmosphere.

How did you get into writing fiction?

This is just recreation. I wrote it to relax, because it was fun to write. It was cheaper than therapy and less damaging than liquor.