The Manga Guide to Relativity

This book begins with an evil headmaster who, during the closing ceremony of school, tells the junior class that he's going to throw a dart at a spinning "Wheel of Destiny." Whatever subject it lands on, the students have to learn about over the summer. It lands on Relativity, which pleases the headmaster, but the students - who have already made summer plans - are rightfully upset at this last-minute task. When student body president Ruka Minagi intervenes, however, he's offered a new deal: he can take on the challenge and the rest of his class goes free, but if he fails, he becomes the headmaster's personal secretary for his entire senior year.

Minagi accepts, with physics teacher Alisa Uraga stepping up with an offer to teach him relativity. The book recounts their summer spent discussing the concepts at the heart of relativity.

As mentioned above, the plot is fairly weak, but the point of the book is the science, and that's pretty spot on. It is a fairly comprehensive look at the subject of relativity, with most of the major topics covered. At the end of the book, the reader should have a fairly good grasp of the science of relativity, so it certainly serves the job of a primer on the subject.

This is probably one of my favorite in the "Manga Guides" series, because the graphical nature of the approach really lends itself fairly well to conceptual graphics for ideas within relativity. This is a difficult topic to get your head around, and they approach it in a way that I think really solidifies the core concepts. There is mathematics brought in, but it's presented in a way that someone with a solid grounding in high school geometry and algebra will easily feel comfortable with.

The first three parts of the book (the first 114 pages) is mostly focused on the theory of special relativity, which is the more specific case of Einstein's theory, which ignores the ideas of acceleration and gravity. Special relativity is a theory that can be applied when you're considering objects that are moving at a constant speed relative to each other. The book well presents the various problems that Einstein (and others) encountered when trying to extend our normal thinking into realms near the speed of light, which motivated Einstein's development of the theory in the first place.

"Part 1: What is Relativity?" covers the following main subjects (some of them further broken up into more detailed sub-headings or grouped under broader collective headings):

• Galilean Principle of Relativity
• Newtonian Mechanics
• What is Light?
• Simultaneity
• Vector Addition of Motion

"Part 2: What Do You Mean, Time Slows Down?" pretty much devotes its entire 30 pages to the subject of time dilation.

"Part 3: The Faster an Object Moves, the Shorter and Heavier It Becomes?" covers the following main subjects:

• Length contraction
• Lorentz transformations
• Relationship between mass and energy
• Muons with extended life spans

"Part 4: What is General Relativity?" expands the theory from the special relativity case to include consideration of acceleration and gravity, which Einstein realized were the same thing. The basis of his theory is that if you were properly accelerating, you wouldn't be able to tell the difference between that and being within a gravitational field.

• Equivalence principle
• Light is bent by gravity (gravitational lensing)
• Time is slowed down by gravity
• True nature of gravity in general relativity
• Black holes
• Global Positioning System and relativity

One warning on this one is that there is a section of the book which takes place near a pool, and the artists use the traditional manga approach to female swimwear. In other words, the physics teacher is in an unnecessarily skimpy bikini. I'm not a prude about such things, but now that I have young children I do find myself noticing it and wondering if it's really necessary to make it that skimpy. In a physics book, especially, it tends to stand out.