Sunday, March 16, 2008

Bye-Bye Moon

On the flight back from France yesterday, I read Jack McDevitt's 1998 SF novel Moonfall. It takes place in 2024, in a generally peaceful and prosperous world that has solved many of today's problems and has developed extensive commercial and government sponsored space programs, including a private fleet of airliner-like SSTO (single stage to orbit) spaceplanes that fly regularly from special underground launch tunnels at various airports around the world and land on long but otherwise normal runways. They carry passengers on fast suborbital flights to distant cities and to space stations in low and geosynchronous orbits. A moon base has also been established (with over 600 people) and is about to be officially opened by the visiting vice president of the United States. A VASIMR-powered interplanetary spacecraft has also been built and is about to depart for the first human mission to Mars.

So far, so good. I'm not sure we're on track to have that much stuff going on in space by 2024, but it's plausible and hopeful. But that's just the background for the disasters that are the main thrust of the book. The main suspension of disbelief that is needed for the story is in the detailed setup. While the VP is on the moon to open the moon base, there is also a total solar eclipse, and this allows the detection from Earth of a previously undetected sun-grazing comet (hard to see without a convenient eclipse). The comet is huge and unbelievably fast (apparently coming from outside the solar system), and it is just five days away from a direct hit on the moon.

There is no way to stop it, and the moon will be destroyed. There are problems with evacuating the moon base and with predicting what will happen to the debris from the moon's destruction - will any of the fragments hit the Earth? You bet! There are many characters and subplots that show us the kinds of problems this event could cause. The characters and situations are generally believable, as are the effects of the bombardment of the Earth, and most of the technology.

The moon and the Earth have both been hit by many huge objects over our ~4 billion year history, and we could be hit again any time. There could be sun-grazing objects coming from the Oort cloud or from some exploded star, and it's possible that one of these could hit the moon or the Earth with disastrous consequences. The eclipse, the five-day warning, and the Veep on the moon are obviously contrived to set up a complex disaster novel. But stranger things have happened, and it mostly worked for me. Smaller objects hitting the moon or the Earth are more likely, and I think we ought to be preparing for this, as advocated by the B612 Foundation.

This was the first McDevitt book I've read, and I liked it. Setting up the various characters and situations was sometimes slow, but it all paid off in the second half of the book. It certainly held my interest and made me want to check out some of McDevitt's other books.

The loss of the moon would have some serious long-term consequences for the Earth (changes in the Earth's rotation, tides, and axial tilt stability, among others). The scientists in this book discuss some of them, though the story focuses more on the short-term "fallout" and the plucky resourcefulness of the characters. You can learn more here, here, and somewhat humorously here. There is also a 1993 book, What If the Moon Didn't Exist?, which seems to be out of print.

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