Why Does the Speed of Light Change How Time Works?

🎧 The Sleepy Scientist is also available on Spotify, if you'd prefer to listen there: https://open.spotify.com/show/0340wK7zF0FYrtTZLWIfzC Time seems to pass at the same steady pace for everyone, but Einstein's theory of relativity reveals something extraordinary. The speed of light is not simply a measure of how quickly light travels through space. It is a fundamental feature of the Universe that determines how space and time are connected. In this gentle exploration of modern physics, we discover why moving clocks run differently, how travelling close to the speed of light can change the amount of time you experience, why two people can age by different amounts, and why there is no single universal present moment. Along the way, we'll explore Einstein's light-clock experiment, the twin paradox, spacetime, length contraction, gravitational time dilation and the remarkable experiments that have confirmed these predictions. From the behaviour of particles travelling through Earth's atmosphere to the atomic clocks aboard navigation satellites, the strange nature of time is far more than a theoretical curiosity. It's an essential part of the physical world we inhabit. Settle in, make yourself comfortable, and enjoy a slower journey through one of science's most remarkable discoveries: time is not quite as absolute as it seems. Thank you for spending part of your evening with The Sleepy Scientist. SOURCES: NASA Science — Universe Glossary: Special Relativity, Time Dilation and the Speed of Light https://science.nasa.gov/universe/glossary/ National Institute of Standards and Technology — CODATA Value: Speed of Light in Vacuum https://physics.nist.gov/cuu/Constants/Value/c.html Einstein Online — Special Relativity: The Relativity of Space and Time https://www.einstein-online.info/en/relativity_space_time/ Einstein Online — From Light Clocks to Time Dilation https://www.einstein-online.info/en/spotlight/light-clocks-time-dilation/ Einstein Online — The Definition of Now https://www.einstein-online.info/en/spotlight/now/ Einstein Online — Time Dilation https://www.einstein-online.info/en/explandict/time-dilation/ Einstein Online — The Case of the Travelling Twins https://www.einstein-online.info/en/spotlight/twins/ Einstein Online — The Dialectic of Relativity https://www.einstein-online.info/en/spotlight/dialectic/ CERN Document Server — Measurements of Relativistic Time Dilatation for Positive and Negative Muons in a Circular Orbit https://cds.cern.ch/record/878581 National Institute of Standards and Technology — Relativity and Optical Clocks https://www.nist.gov/publications/relativity-and-optical-clocks National Institute of Standards and Technology — Putting Einstein to the Test https://www.nist.gov/atomic-clocks/a-powerful-tool-for-science/putting-einstein-test National Institute of Standards and Technology — Clock Experiment Demonstrates That Your Head Is Older Than Your Feet https://www.nist.gov/news-events/news/2010/09/nist-clock-experiment-demonstrates-your-head-older-your-feet Einstein Online — How Time Is Made https://www.einstein-online.info/en/spotlight/how-time-is-made/ LIGO Laboratory — All About Gravitational Waves https://www.ligo.caltech.edu/WA/page/gravitational-waves Nobel Prize — The Nobel Prize in Physics 2022: Quantum Entanglement and Bell Inequalities https://www.nobelprize.org/prizes/physics/2022/press-release/