Marianne J. Dyson

Review of Life As We Knew It

Reviewed by: Marianne Dyson, Review revised July 2009. See final paragraph.

The Science Fiction and Fantasy Writers of America, of which I am a member, nominates and votes on stories and books for the Nebula and the Norton awards. Life As We Knew It by Susan Pfeffer qualified for the final ballot (was nominated for the Norton award), so I read it to decide how to vote.

The premise of the book is that an asteroid striking the Moon causes it to move closer to Earth, totally disrupting the Earth's climate and wrecking havoc on the lives of its human occupants. While a large asteroid striking the Moon is possible, even likely given enough time, the odds of it being large or dense enough to significantly change its orbit are, well, astronomically slim. But given that it could happen, it could definitely not happen the way it is described in this book.

In the book, the asteroid strikes the Moon when it is in quarter phase (half full). This phase happens twice a month, once when the eastern half of the Moon is visible at sunset, and once when the western half of the Moon is visible at sunrise, i.e. when the Moon is on opposite sides of the Earth in its orbit. It is as physically impossible to see a quarter-phase Moon in BOTH the morning and evening of the SAME day as it is to see the Sun at noon and midnight. Yet on page 10, it says, "This morning...I remember seeing the moon in the sunrise sky. It was a half moon, but it was clearly visible and I... thought about how tonight the meteor was going to hit it..."

Which brings me to the next error: meteor. Should we let the author and editor of this book off the hook because a lot of people mix up the use of meteor and meteoroid? I think not! Many people misuse terms in casual conversation, but if you are writing a book for publication, especially for young impressionable readers, you owe it to them to get it right. And an editor should question terms used by authors, especially if they are integral to the plot. If either of them had taken time to check Webster's, they would have known that a meteor is "an atmospheric phenomena 2a: any of the small particles of matter in the solar system that are directly observable only by their incandescence from frictional heating on entry into the atmosphere, b: the streak of light produced by a meteor." A meteoroid is the particle itself while in orbit around the Sun. Anything large enough to be seen without a telescope as described in the book is either an asteroid or comet. (In case you were wondering, a meteorite is that part of a meteoroid that makes it to the ground after it has been a meteor!)

The main character is a 16-year-old girl named Miranda. The story takes place in a small town in Pennsylvania. On page 18, she joins the neighbors to watch the impact on a clear night in May at 9:30 PM. Miranda's brother spots the asteroid first in his telescope. Then they all see "the biggest shooting star you could imagine. It was a lot smaller than the moon, but bigger than anything else I'd ever seen in the sky. It looked like it was blazing..."

Asteroids do not blaze. Only comets have tails. Shooting stars are meteors, an atmospheric phenomena. The Moon has no atmosphere.

"And then it hit. Even though we knew it was going to, we were still shocked when the asteroid actually made contact with the moon." Two paragraphs later "the moon wasn't a half moon anymore. It was tilted and wrong, and a three-quarter moon and it got larger, way larger, large like a moon rising on the horizon, only it wasn't rising. It was smack in the middle of the sky, way too big... You could see details on the craters even without the binoculars that before I'd seen with Matt's telescope. ... It wasn't like a big chunk of it flew off into space. It wasn't like we could hear the sound of the impact, or even that the asteroid hit the moon dead center. It was like if you're playing marbles and one marble hits another on its side and pushes it diagonally."

It is impossible for the Moon to change from half to three-quarters full in any short period of time. The Moon is not a stationary target. It revolves around the Earth like a ball on a string with the string being its gravitational attraction to Earth. Seen from the north, it goes counterclockwise. It normally takes the Moon about 700 hours to orbit Earth. At a distance of 240,000 miles, it is moving at about 2,100 mph. To move from half to three-quarters, the Moon must travel 1/8th of the circumference, 2piR (2pix240,000=1,500,000 miles) of its orbit, or about 187,500 miles. Only two paragraphs elapse in the story, but let's say an hour passes before the Moon reaches the observed three-quarter phase. This means the Moon's speed has increased to 187,500 mph! At this speed, the Moon would be ejected from the Solar System!

In later chapters, we are told that the Moon has moved closer to Earth. This requires the Moon to slow down, not speed up, just the opposite of what is needed to make it change from half to three-quarters full. But let's pretend that Miranda mistook an increase in size for a phase change. From her description of the Moon looking magnified like it does in a telescope, we can estimate its new distance. A typical small telescope or binoculars magnify the Moon about 50 times. The Moon is 2,000 miles in diameter and subtends ½ degree. For it to be 50 times bigger, it has to subtend 25 degrees. The distance is found by drawing a triangle with the vertical end being 1,000 miles (half of 2,000) and angle 12.5 degrees (half of 25). The tangent of 12.5 equals 1,000 divided by the "flat side" of the triangle which is the new distance. The distance is then about 4,500 miles (2,800 km) from the surface of Earth (8,500 from the center).

Conservation of angular momentum requires that the new orbit be an ellipse with the closest distance 8,500 and the farthest remaining where it was, 240,000 miles. Using Kepler's third law, the period is calculated to be 10 days. The Moon would be huge for a very short time during perigee, and return to regular size during apogee. The order of the phases would not change, but having a full moon every ten days would surely upset many animals' reproductive and predatory behaviors. The length of Earth's day would gradually lengthen from the friction of the increased tidal effects.

The amount of energy required to move the Moon either the 187,500 miles to change phase (or the 231,500 [240,000 minus 8,500] to move it closer) is incredible. Is it even possible to accomplish with an asteroid? Astronomers in the real world would know the velocity of an asteroid very precisely, but not the mass. That's because all objects fall at the same rate in a gravity field, just like Newton proved centuries ago, and Apollo astronauts demonstrated by dropping a feather and a hammer on the Moon and watching how they hit the surface at the same time. Typical asteroids falling toward the Sun speed past the Moon at 40,000 mph. [Lowell Observatory] The mass times the change in velocity of the Moon squared should equal the mass times the velocity squared of the asteroid. To balance the equation, the asteroid has to have one fifth the mass of the Earth!

Miranda says the asteroid is much smaller than the Moon. Let's say it is about one-fourth the size of the Moon. If the mass is one fifth the mass of Earth, that yields a density of about 5 million kg/cubic meter! Metallic asteroids are made of iron and nickel. Iron has a density of 7800 kg/cubic meter, and nickel 8900. Obviously, the object that hit the Moon was not an asteroid! The only naturally-occurring item I can think of that is more dense than metal would be a white dwarf. But the smallest white dwarf would be the size of the Earth and vaporize the Earth's oceans as it passed by. It would also have a density in the billions of kilograms/cubic meter. A neutron star would be small enough, but the density is 1 times 10 to the eighteenth power. A neutron star could pass through the Solar System at high speed, but I don't think anyone would survive to watch it vaporize the Moon.

And what about Newton's third law: for each action there is an equal and opposite reaction? An object striking the Moon would absolutely send up a cloud of debris in the opposite direction. I suspect that if an object large enough to see with the naked eye hit the Moon, a good portion of the Moon would be vaporized. The "left eye" of the Moon (Imbrium) is the size of Texas. Geologists estimate that the object that made it was only 62 miles in diameter. Enough material was thrown out by this explosion to cover the whole Moon about a thousand feet deep.

So this whole scenario is impossible.

The author also did not understand how basic technology works. One of the first things Miranda discovers after the impact is that the Internet is down. The Moon's new elliptical orbit would wreck satellite communications. Navigation and military surveillance would "crater," (sorry, couldn't resist), but the Internet would hardly be affected because it is mostly a ground-based system. National and dish TV stations would be "impacted" too, but not local ones, cable or otherwise. As long as they have power, they should all work just fine. Cell phones are also mostly independent of satellites, though GPS functions would not work.

Most of the problems encountered by Earthlings in the book are a result of tsunamis wiping out all coastal cities, halting shipping and causing power blackouts. If a chunk of the Moon had come off (see above), it would very likely have struck the Earth and landed in water, causing a tsunami. But the author specifically had Miranda tell us that no chunks came off! That leaves earthquakes. Would the Moon moving closer cause earthquakes? Probably. With the Moon at 0.019 its previous distance for at least one day of its new ten-day cycle, its gravitational pull would be 2770 times greater. Still, I think earthquakes and volcanoes would be limited to the usual places. I don't know the geology of NYC. I suspect Tokyo would be in trouble. Would the tides go from a few feet to thousands of feet when the Moon is at perigee? It is a very complex problem, but I'd guess yes. The water would rise and then recede to rise again ten days later. Not a tsunami, but more than enough to destroy most coastal cities, and maybe, as stated in the story, wash the Statue of Liberty out to sea.

Given that there are earthquakes and that volcanoes become more active, it follows that the air gets choked with smoke and ash, causing a temperature drop, as happens in the story. Would it get cloudy enough for it to freeze in Pennsylvania in August? I don't know. If everyone in Pennsylvania cuts down tree after tree to burn as firewood day and night like this family, the air would be choked with smoke even without the volcanoes. I'd expect a lot of fires, too. But the mother of the story should have asked a scientist before telling her daughter to boil their water. She says, "We should boil our drinking water from now on... if the air is badly polluted, we shouldn't take chances."

Boiling removes water as steam, leaving less of it in the pot with the pollutants. In other words, boiling the water CONCENTRATES any particulates, like boiling the water out of a sauce thickens it. Boiling does kill organisms and germs. If the local water filtration plant is not working, then they are at risk of cholera, and should indeed boil their water. To remove pollution, the boiled water needs to be filtered. Pouring it through a cotton cloth or linen napkin would take care of most contaminants. An aquarium filter would be even better. Pure water could be obtained by condensing the steam from boiled water.

Even without the bad science, the story and characters just didn't appeal to me. (The Postman by David Brin was a far superior handling of an end-of-the-world story.) This family selfishly hoarded their food and supplies. They worried more about the little brother getting his chance at baseball camp than in learning what they could do to help themselves and their community survive the crisis (such as learning how to properly treat water!). Other than the oldest son volunteering at the post office, they never help anyone, yet expect the community to provide for them, and go to great lengths to make sure they get "their share." The mother even berates the daughter for informing her boyfriend about a food distribution instead of holding her place in line. While holding up this greedy mother as a role model, the only Christian in the story is protrayed as a poor deluded girl who stupidly shares her lunch with those in need instead of keeping herself healthy. The mother's ranting against the president's offer of prayers adds to the author's diatribe against Christians. The only hero is a doctor whose help and sacrifice is taken for granted because of his relationship to the mother.

It is ironic that the family survives not because of any particular skills or knowledge (the mother spent her time studying French—really useful for survival!), but because others in their community and nation work together to restore basic needs and willingly share resources with this family. But the book doesn't really end, it just stops, leaving dozens of loose ends such as the fate of the father or the skater that are important to the main character.

If young people are interested in surviving a real future disaster including a rare but possible impact from space, they might fill their heads with useful information such as how to build a generator, treat basic illnesses/injuries, recycle water, and grow plants with artificial lights. With this knowledge plus some understanding of orbital mechanics, they can live anywhere, be that on a crowded disaster-challenged Earth or in a lovely space colony on the Moon.

Originally, I gave Life As We Knew It only 1 point, for readability/grammar because the diary format worked well for this topic, and the teen voice sounded authentic. The book lost points for impossible science, incorrect use of terms, lack of new ideas, a plot with no basis in reality, and not very likeable characters. Because of the science content, I did not vote for the book to win the Norton, and was glad that it didn't win. But years later, people are still talking about this book. It has raised awareness of the danger that asteroids pose to Earth. So though I still do not recommend the book, I have decided to raise its ranking from 1 to 2.

Title: Life As We Knew It
Author: Susan Beth Pfeffer
Ages: Young adult
Format: hardback
Pages: 337
Publisher: Harcourt, Inc.
Date: 2006
Retail Price: $17.00
ISBN: 978-0-15-205862-5

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