Particle pac man
“Agent Higgs,” Test Tube Games

Ever since physicist Peter Higgs proposed its existence in 1964, scientists have been searching for the Higgs boson, an elementary but still hypothetical particle that may help explain how mass forms. But they haven’t found it — and in “Agent Higgs,” you’re not about to make that search any easier. The goal of this Tetris-style puzzle game, which runs on the iPhone, is to help the Higgs boson hide from physicists. Players shove a series of purple blocks, which represent neutrinos and electrons, around the game board in order to reach the clandestine particle — disguised in a Groucho-style moustache and glasses — thereby concealing him from scientists. It’s mostly in the name of fun, but there are a few lessons to be learned in the utility of the different blocks. Neutrinos, for instance, can pass through solid matter; and if you shove matter into antimatter, you get a very big boom.

Spheres in motion
“The Ballet of the Planets,” Oxford Press

In “The Ballet of the Stars,” mathematician Donald C. Benson traces the study of planetary motion from the early Earth-centric model, which presumed that everything revolved around us, toward a more clear-headed concept of the cosmos, where the Earth and its fellows revolve around the sun.

Figuring out why the planets move through the night sky the way that they do was, according to Benson, a major step in the evolution of scientific reasoning: collecting data, forming theories and challenging assumptions. “The motion of planets was very puzzling to early scientists, because, over a period of weeks, the positions of the planets relative to fixed stars changed in a manner that was difficult to explain,” he writes. That is, rather than following a straight line, the planets sometimes appear to exhibit retrograde motion, seemingly making loop-the-loops through the night sky. These data directly challenged the early notion that the objects in the heavens moved in concentric circles — because if they did, how would anything flip around? Benson recounts the complex theories that were developed to account for this motion yet still keep Earth in the middle of the universe, before they were eventually challenged by Copernicus, who had a simpler explanation: That planets actually moved in ellipses and that the backward motion of the planets was an Earth-based illusion.

Aaron Leitko