![]() So don't worry about blinding any astronauts. Depending on your laser, it might be 500 or 1,000 kilometers across. And as you may have guessed, the red dot of a laser pointer is pretty big by the time it gets to the moon. No physical laws are broken, because nothing physical is actually traveling faster than light. Each photon travels to the moon at the speed of light, but the image of a dot that they form on the surface moves 20 times faster. The laser pointer on the moon is basically the same. But if you cleverly arrange a whole bunch of pixels to turn on and off in a special way, you can make an image that appears to move across the screen, even though every pixel stays put. What's the speed limit for pixels on the screen? Zero. How is this possible? Well, think about a computer screen. The spot of light from the laser beam will travel across the moon's face in about half a millisecond, which means it's traveling at 20 times the speed of light. All you have to do is point a laser beam at the moon and flick your wrist. NEC Research Institute, 4 Independence Way. ![]() Lijun Wang, Alexander Kuzmich, and Arthur Dogariu. And while this implies that nothing with real mass can move faster than light, it doesn't impose a cosmic speed limit, because you can break the speed of light in your backyard. Detailed statement on faster-than-c light pulse propagation. ![]() All that Einstein said was that light moves at the same speed in every reference frame. Nothing can travel faster than the speed of light. You may have heard that Einstein's theory of special relativity imposes a cosmic speed limit. SpaceNext50 Britannica presents SpaceNext50, From the race to the Moon to space stewardship, we explore a wide range of subjects that feed our curiosity about space!.Learn about the major environmental problems facing our planet and what can be done about them! Saving Earth Britannica Presents Earth’s To-Do List for the 21st Century.Britannica Beyond We’ve created a new place where questions are at the center of learning.100 Women Britannica celebrates the centennial of the Nineteenth Amendment, highlighting suffragists and history-making politicians.COVID-19 Portal While this global health crisis continues to evolve, it can be useful to look to past pandemics to better understand how to respond today.Student Portal Britannica is the ultimate student resource for key school subjects like history, government, literature, and more.This Time in History In these videos, find out what happened this month (or any month!) in history.#WTFact Videos In #WTFact Britannica shares some of the most bizarre facts we can find.Demystified Videos In Demystified, Britannica has all the answers to your burning questions.Britannica Explains In these videos, Britannica explains a variety of topics and answers frequently asked questions.Britannica Classics Check out these retro videos from Encyclopedia Britannica’s archives.
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