Science Seen

Time One author Colin Gillespie helps you understand the physics of your world.

What is Planck-scale physics and why does it matter?

The Planck-scale physics story begins long ago. In 1901 German physicist Max Planck publishes an explanation for strange properties of radiant heat. He says its energy is quantized. In other words, it radiates in distinct little bits. He sees this as a mathematical convenience and doesn’t really believe it. His math requires a constant he […]

Twin mysteries: A ghostly fundamental particle and a physicist who disappeared after saying its antiparticle may not exist

Twin mysteries arose around 1937 when Italian theoretical physicist Ettore Majorana suggested neutrinos are their own antiparticles. Soon afterward he took the night ferry from Palermo to Napoli and vanished, leaving us to ask: What happened to him; and was he right? The Standard Model has a place for every known elementary particle. It says […]

Understanding time travel . . . and travel time

Albert Einstein predicted time travel in 1905. It was demonstrated in 1971 and many times since. The twin paradox provides a dramatic illustration of time travel: You travel to a distant star and return to find you are far into your twin’s future. No-one has done this; but it is a real effect. It has […]