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Slow Light

4 February 2015

Animated video demonstrating the speed of light. Credit: Alphonse Swinehart, via Vime

We think of light as being extraordinarily fast. It’s so fast that a beam of light could travel from New York to Los Angeles in about a hundredth of a second. If anything can be called fast, then that ultimate speed limit must surely qualify. And yet, on an astronomical scale, light is tediously slow. Our solar system is a mere speck in the vast scale of the cosmos, and yet light takes time to journey even that speck.

You can get a feel for slowness of light in the video, where the journey of light is shown in real time. From the instant it leaves the Sun’s surface, to just past Jupiter takes nearly three-quarters of an hour. A video showing the journey all the way to Pluto would take more than 5 hours. It would take about 18 hours to reach Voyager 1. All that time to take the smallest step into the universe.

As you watch this video (or part of it) keep in mind that this isn’t a representation of “rocket speed,” or any speed we can remotely achieve. It is the limit of all possible speeds. It is the expanding sphere of influence for anything we do. We are bound by that speed, as is everything else in the universe.