How fast speed of light

This would mean that if you were on a spacecraft travelling at The problem is by the time you return to planet Earth everybody else would have aged around 9 years. So maybe there is hope for interstellar travel within a human lifespan after all.

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A Number Trick. Designing a High Altitude Balloon. Calendar Calculations. Telling Time by the Stars - Sidereal Time. Fields, an Heuristic Approach. The Irrationality of. The Number i i. The Transcendentality of. A traveler, moving at the speed of light, would circum-navigate the equator approximately 7. By comparison, a traveler in a jet aircraft, moving at a ground speed of mph, would cross the continental U.

Related: What if Earth had rings? But by doing thought experiments, physicists have determined that unusual things would happen if humans could travel at near light speed, said Kortemeyer, who is also an associate professor of physics at Michigan State University. According to Albert Einstein's theory of special relativity — which explains how speed affects mass, time and space — time would slow down, we would measure objects as being shorter as we whizzed past them and the Doppler effect would become visible for light, among other changes.

Those same changes would occur if, instead of humans speeding up, light slowed down. In both cases, we'd be moving at near light speed. While Kortemeyer was working as a visiting professor at MIT, he, Tan and colleagues at the MIT Game Lab created a computer game to illustrate what the world would be like if the speed of light were slow enough that special relativity were noticeable in everyday life. In the game, released in and called " A Slower Speed of Light ," the player controls a character who collects beach ball-like orbs.

Every time the character collects one of the orbs, the speed of light slows. In reality, the speed of light would not slow down the way it does in the game.

The speed of light in a vacuum never changes and is constant for every observer. However, the speed of light does change depending on the materials it's passing through, but that doesn't change the effects of special relativity, or how we perceive them, Kortemeyer said. If we could witness special relativity, however, we would notice changes in colors, time, distance and brightness, and the team incorporated those effects into the game.

When the speed of human motion approaches the speed of light, something called the relativistic Doppler effect becomes perceptible. To understand this, remember that light acts as both a particle and a wave.

As a wave, it's characterized by its wavelength, or the distance from crest to crest, which determines its color, and its frequency, or how many crests pass in a given time.

Related: What if there were no gravity? Similar to the way that, according to the Doppler effect, approaching a sound source makes its frequency, or pitch, seem to increase as the wave crests reach your ear faster and faster, moving toward a light source makes its wavelength seem shorter, shifting the apparent color of the light toward the blue and violet end of the color spectrum, Kortemeyer said. Moving away from an object, on the other hand, shifts its apparent color toward the red end of the spectrum.

In sum, "the thing coming toward you looks bluer, or the thing moving away from you looks redder," Kortemeyer said. Perhaps one of the most famous effects of special relativity is that for a human moving near the speed of light, time slows down.