Particle Express

You are an electron. Race along a line, break out into a plane, then into space, and on into a fourth dimension that nobody has ever found.

Everything you meet is real particle physics, and you use it to win:

• Tunnel through walls as a quantum wave: hold SPACE, and let go to pay back the energy you borrowed. • Flip your spin to slip past other electrons and through spin filters. • Fly through a Higgs field and become a heavy muon that goes straight through lead. • Take energy from accelerator cavities, dodge photons and positrons, and watch time dilation on the muon's clock. • At full energy, meet a positron head on and make a Higgs boson, drawn the way a detector sees it. • Then, a "what if": a fourth dimension that you step through with Q and E, and a microscopic black hole at the end.

Race three rivals, an electron, a muon and a tau at gold, silver and bronze pace, and your own best run. A notebook explains everything you meet: what it does in the game, and what is true in real physics. The physics has been fact-checked, and the game says plainly which parts are game rules and which are "what if".

CONTROLS Hold SPACE or the mouse button: tunnel F or right click: flip spin Arrow keys, WASD or the mouse: steer Q and E or the mouse wheel: step through the fourth dimension V: change how the fourth dimension is drawn (six ways) B: brake P: stop and read the notebook L: full screen M: sound C: calm effects

ON A PHONE OR TABLET (turn it sideways) One thumb slides anywhere to steer The other holds the SPACE button to tunnel and taps F to flip spin In four dimensions, the Q and E buttons step STOP opens the notebook

A run takes 3 to 5 minutes.

The game has no ads and no tracking. Your best time and your notebook are kept only in your browser.