There is a hypothetical class of particles that always travel faster than light. Einstein himself played around with the idea, calling them “ meta-particles,” but today we call them tachyons, a word ...

When you think about the idea of time travel, you likely think about the fantastic possibility of going backward in time to an event in the past, rather than our constant, inevitable march forward in ...

An Extraordinary Particle Could Travel Back in Time, Scientists Say. The potential is tantalizing. By Tim Newcomb Published: Feb 21, 2023 3:05 PM EST. 1. Xuanyu Han // Getty Images.