
How Scientists Detected Negative Time
Every morning, the sun rises and the second hand on your watch clicks forward in a steady march from yesterday to tomorrow, governed by the strict sequence of the arrow of time. In this episode, we explore the strange world of quantum mechanics, where physicists have uncovered evidence suggesting that time can be negative and run backward. We trace the mystery of quantum tunneling—where particles like electrons or photons use wave functions to seep through energy barriers rather than climbing over them—and examine how early theoretical models of "negative group delay" were initially explained away as wave-reshaping illusions that protect Einstein's cosmic speed limit. Finally, we investigate groundbreaking experimental evidence from a University of Toronto team led by physicist Aephraim Steinberg, who used weak measurement techniques and ultracold rubidium atoms to probe atomic excitations, revealing that transmitted photons can interact with their surroundings for a negative duration of time.