Marianne J. Dyson

Review of

Reviewed by: Marianne Dyson, February 17, 2007

Midnight on the Moon is actually the book that convinced me that I should start reviewing children's books based on their science content. I got this book at a school book fair during an author visit years ago. I read it during my lunch break, and moaned so much that the librarian asked me what was wrong. I explained to her that I had finally found the reason that so many children think that a lack of air means there is no gravity: it was in this book! Because it was published back in 1996, I thought it had gone the way of other popular series until I saw it again at a book fair last month. Argh! Tens of thousands of children may now have their heads filled with misconceptions about gravity and space! I apologize to all of you for not warning you about this book sooner (though thankfully, I see that several others noted the bad science in their reviews).

The series is about a brother and sister, Jack and Annie, who have a tree house that is filled with books. The tree house is magic and will take the children to any place illustrated in one of the books. The tree house belongs to a magical librarian who traveled through time and space to gather books for her library. She is under a spell, and the children have to find special things to free her.

In this book, the children are searching for an "M" thing. They point to a picture of a dome-shaped structure in a library book called "Hello Moon" found in the tree house. The first Moon facts are on page 9 where Jack says, "There's no air. We couldn't breathe." This is true. "Not only that, we'd boil to death if it was day and freeze to death if it was night." This is misleading. In addition to most children interpreting "boiling" as cooking something in water, exposure to heat and cold would probably not be the cause of death on the Moon. The lack of air would do it. Not because you couldn't breathe, but because all the air and liquid would be sucked out of your body through every opening (mouth, nose, eyes, ears, anus, pores, etc.) simultaneously. It is still debated whether or not the body would explode or "deflate," but it would not boil because of heat. I don't know of any experiments that prove this, but I suspect a body would at least initially freeze in vacuum even in the daylight because so much heat is lost so quickly through evaporation. It would then heat up to some equilibrium temperature.

The tree house lands inside a moon base that the library book tells the children was built in 2031. "The top of the dome slides open to let spacecraft enter and leave....Air and temperature controls make breathing possible." How temperature controls make breathing possible is not clear. Certainly air that was so cold it turned to a solid, or so hot as to become ionized would not be fit to breathe.

Jack leaves the tree house, goes up some stairs, and looks out a window with Annie. No mention is made of how much easier it is to move in the low gravity. They see "a rocky gray land...filled with giant craters and tall mountains. The sun was shining. But the sky was ink-black!" These statements are accurate. I was glad no mention was made of stars. The stars are there, but not visible because human pupils contract in bright light.

The library book informs the children that a day on the Moon is fourteen Earth days long. This is correct. Then it says, "No air protects the moon from the sun's rays, so daytime heat reaches 260 degrees." This is misleading because temperature and heat are not the same thing. The average temperature of the surface of the moon in daylight is 225 degrees F (-22 to -58 at poles). The heat energy would be measured by how much its temperature changes. A surface's temperature depends on how much heat energy it absorbs before it reaches equilibrium. A piece of white paper and a piece of black paper would have different temperatures on the surface of the Moon just like they do in sunlight on Earth. Air does protect Earth's surface from some of the sun's rays, specifically the high frequencies, and clouds do provide cooling. But it does not follow that if the moon had air, it would be cooler. Venus has thick clouds and a surface hotter than that of Mercury! Sorting out the factors in heat transfer in planetary atmospheres is incredibly complicated.

Jack then tells Annie that their blood would boil if they went outside. It would, but again, not because of the heat.

The next quote Jack reads from the library book that explains that spacesuits keep scientists from getting too hot or cold and supply air for them to breathe. Thermal control in NASA spacesuits is actually provided by the undergarment that is laced with tubes full of water. Pumps circulate the water and provide cooling, though air flows over the head to keep the face cool and dry. Heaters are only needed for hands and feet because exercise generates heat. If a spacesuit were put on over clothes the way the children do it, they would likely overheat and cook in their own juices in less than a half hour (firefighters last about 15 minutes).

An airlock is a lock, and requires at least two hatches to seal it shut. When the children press an "OPEN" button, a door slides shut behind them and then the other one opens. This is good. We must assume there was time for the air in the lock to be vented back into the dome. Otherwise, the air trapped in the lock with them would explode outward and send up quite a cloud of dust.

Standing outside the airlock, Jack reads from the library book that "the moon has no rain or wind to blow dust around. So footprints will never wear away naturally, not even in a billion years." It is true that no wind or rain will disturb footprints, but there is another natural process that does "weathering" on the moon: impacts. There is no air to stop even small meteorites, so the moon's surface is constantly "sandblasted." Over a billion years, I suspect that many footprints would be covered by dust and some of them buried by falling debris.

Jack would see Earth only if he were on the near side of the Moon. Their location on the near side is later confirmed. However, he would not see any blue and white ball because when the Moon is full (as stated in the text), the Earth is in new phase as seen from the Moon. (They are always in opposite phases.) What Jack would see is an outline of the atmosphere, and perhaps a tiny crescent if the Moon is not exactly full. This error is repeated in the cover illustration, and on an interior illustration on pages 28, 34, and 45. The one on page 34 is especially bad because it shows the Earth low to the horizon behind the Apollo 11 flag. The Apollo 11 landing site is almost on the lunar equator, and the Earth would be directly overhead at all times. (The Earth does not rise and set on the Moon because the Moon always keeps one face toward Earth.)

The worst mistake in the whole book is on page 27. "A person weighs less on the moon because of the moon's low gravity and lack of air." No, no, no! The lack of air has NOTHING to do with a person's weight! Weight is a measure of mass, and gravity depends only on mass and distance.

This error is perpetuated in the actions that follow. The children jump around like "moon rabbits" and Jack feels "light as a feather." These are good descriptions, but they would have felt these effects WHILE STILL IN THE DOME.

The children then bounce around, Jack falls down, and Annie helps him up. They discover a moon buggy, and take it for a ride. This is okay as long as we assume this is a "modern" buggy and not one left from Apollo. The Apollo rovers were battery-powered, and those batteries are long dead.

They drive the rover and end up at the Apollo 11 landing site. First of all, the flag fell over when they lifted off the moon. Secondly, after more than 30 years of exposure to the Sun, it is probably not red, white, and blue any more (unless, as one author speculated recently, dust covered it enough to protect it). The plaque "Here men from the planet Earth..." is not on a sign. It is attached to the footpad of the lander. The kids would have to be right up beside it to read it. They leave a message by the flag thinking it will never be disturbed. It might not be moved, but if they left it in the Sun, it would bleach out just like the flag.

I also object to this whole scenario because it makes it sound okay for kids to just walk all over this historic site, putting their footprints over top of the Apollo tracks, perhaps kicking dust over the first footprint! If an outpost is established near this site, I feel sure that the area would be protected, fenced or roped off with "Keep Out" signs in English, Chinese, French, etc.

The children are surprised and frightened by the appearance of a mysterious "moon man." (I thought he was a security guard come to haul away the trespassers!) The children decide to race back to the dome and lock the door against him. I seriously doubt that airlocks would be designed to keep anyone out! That would be a major safety issue because a person would die if locked out. And the kids are the ones who are trespassing! Why do they think that this man means them harm? For that matter, why do they assume it is a man and not a woman or robot?

On their way back, they find the "pass" blocked by a giant rock that has apparently fallen from space in the time they were gone! This is just not scientifically credible. Rocks do impact the moon randomly, but a rock that large (described as twice as tall as the girl, so about 8 feet tall) is rare, and would cause an explosion, blast an enormous crater, and cause landslides and a plume of dust that would be visible for miles (and from Earth).

The children jump over the meteorite. A person can jump six times higher in one-sixth gravity, so this is a good solution. They both end up lying down, unable to get up. The Apollo astronauts did have some difficulty getting up, and it is logical to assume that kids in oversized suits would, too.

The mysterious "moon man" catches up with them. Annie realizes he can't hear them and writes him a note. He leaves them a cryptic message. Then they continue to the dome, worried about running out of air. Some license is allowed for design of these future suits, but I can't believe that the air would gradually run out. Yet Jack says, "it feels harder to breathe." More likely, if the level were low, an alarm would sound. Then when the supply ran out, it would simply shut off, though the limiting factor in current suits is not oxygen, but battery power to run the pumps. Anyway, if the oxygen or pumps shut off, the danger would be a buildup of carbon dioxide. Jack would not feel like it was harder to breathe. He would feel confused and maybe a little silly. I have experienced hypoxia (in the NASA hyperbaric chamber as part of the training to fly on the "Vomit Comet") and did not have any difficulty breathing.

They get back to the dome, and take off their suits. "As they moved clumsily into the spacesuit storeroom, Jack felt heavy again." No, no, no! And again, no! Air has NOTHING to do with weight. Gravity depends on MASS (and the square of the distance from the center of mass).

They take the moon man's message back to the tree house and solve the mystery to free the librarian.

So what points do I give this book that has caused so many children to absorb the wrong-headed notion that gravity depends on air? I just can't give it any at all. The book being fiction is no excuse. If it were historical fiction and an illustration showed a computer on George Washington's desk or the text quoted him saying "That's groovy," someone would have noticed. It is a sad commentary on the state of our science education that no one involved with this book apparently understands basic physics enough to at least catch the mistakes about gravity and the phases of the Moon. And it is even sadder that they might have thought it was correct, and therefore didn't bother to run it past a scientist before publication.

I definitely do not recommend Midnight on the Moon! I would go so far as to suggest that librarians remove it from their shelves and not offer it at book fairs to prevent contaminating more young minds with incorrect and misleading information.

Title: Midnight on the Moon: Magic Tree House #8
Author: Mary Pope Osborne
Illustrator: Sal Murdocca
Ages: 9-12
Number of Pages: 70
Format: paperback
Publisher: Random House
Date: 1996
Retail Price: $3.99
ISBN: 0-679-86374-5

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