Science How do scientists know that the particles revealed after a proton or lead ion collision are different from each other, such as quarks and muons, and not just smaller pieces of protons or lead ions? (If I were to smash two lead bullets together, they would break into smaller pieces, but they would still be lead.)
Human Spaceflight, Robotic Spaceflight How do mission designers know at what angle to land on an astronomical body such as the Moon, Mars, or Earth?
