Resumen de Ghosts in the machine
It's not often that cannons get used for target practice. These images show some of the first machines built to emit X-rays, now given a taste of their own medicine. The stark, ghostly quality of X-ray scans have transfixed us for over a hundred years. When you shine an ordinary beam of light at an opaque object, it casts a shadow. But if the light's frequency is sufficiently high, the beam can pass through tissue as though it were transparent. Devices such as those shown here, commonly known as X-ray tubes, generate these high-frequency waves by accelerating electrons into a solid target. If the collision is sufficiently violent, the target atoms can be made to emit X-rays as a way of dissipating the excess energy
