Medicine & the Body
Machines that look inside you without opening you up.
- How an MRI Machine Works — Nothing inside it moves. The image comes from a magnet held 269 degrees below zero by a current that has been going round in circles for years, a radio note played into you at 63.87 megahertz, and the handful of protons — about six in every million — that never bothered to cancel out.
- How an X-Ray Machine Works — No camera, no lens, no film in the modern ones. A wire boiled white-hot, electrons thrown across a vacuum at half the speed of light, and a spinning slab of tungsten that turns 99 per cent of it straight into heat — all to make the one per cent that casts a shadow through you.
- How the Heart Works — It is not one pump. It is two, bolted together and wired to fire 0.1 seconds apart — and the muscle doing the work can only feed itself in the gap between beats.