Is it possible to travel through time? Yes, and you’re doing it right now, traveling through time at an astounding rate of one second each second. You’re always traveling through time at the same rate, whether you’re watching paint dry or wishing you had more hours to visit with an out-of-town buddy.
However, this isn’t the kind of time travel that has attracted innumerable science fiction writers or spawned a genre so vast that Wikipedia counts over 400 titles in the category “Movies about Time Travel.” Characters in films such as “Doctor Who,” “Star Trek,” and “Back to the Future” hop into a crazy vehicle to travel back in time or spin into the future. After traveling across time, the protagonists must decide what happens if they change the past or present with information from the future (which is where time travel stories intersect with the idea of parallel universes or alternate timelines).
Although many people are attracted by the prospect of altering history or seeing the future before it happens, no one has ever proved back-and-forth time travel or developed a mechanism of moving a human over considerable periods of time without destroying them in the process. This is the best proof we have that time travel is not feasible. We haven’t been besieged by swarms of tourists from the future,” wrote physicist Stephen Hawking in his book “Black Holes and Baby Universes,” published in 1994.
However, science does allow for some time travel. The theory of special relativity proposed by scientist Albert Einstein, for example, suggests that time is an illusion that shifts relative to an observer. Time, with all its aftereffects (boredom, aging, etc.) will be experienced considerably more slowly by an observer traveling near the speed of light than by an observer at rest. That’s why, after a year in space, astronaut Scott Kelly aged slightly slower than his identical brother who remained on Earth.
Other scientific hypotheses concerning time travel exist, such as some strange physics involving wormholes, black holes, and string theory. Time travel, for the most part, is the subject of an ever-growing number of science fiction books, movies, television shows, comic books, video games, and other media. Our fastest human spaceships travel at less than a tenth of the speed of light. However, if you can spend a significant amount of time close to the universe’s ultimate speed limit, your clock will run slower. You will go through the time and into the future. Nothing will feel different for you, but when you return to Earth after a few years, our clocks will have advanced by thousands or perhaps tens of thousands of years, depending on how quickly you travel.
General Relativity and Gps Time Travel
Astronauts’ life span in low earth orbit may be negligible but the dilation in time between people on Earth and GPS satellites flying through space does make a difference. The difference is better suited for jokes among siblings than actual life extension or visiting the distant future. The Global Positioning System, or GPS, assists us in determining our exact location by connecting with a network of a few dozen satellites in high Earth orbit. The satellites circle the planet at a speed of 8,700 mph (14,000 km/h) at a distance of 12,500 miles (20,100 kilometers). According to special relativity, the quicker one thing moves in relation to another, the slower the first item sees time.
According to the American Physical Society Publication Physics Central, this phenomenon saves GPS satellites with atomic clocks 7 microseconds, or 7 millionths of a second, per day. Then, according to general relativity, clocks closest to the center of a big gravitational mass, such as Earth, a tick slower than those further away. Because GPS satellites are significantly farther from the center of the Earth than surface clocks, Physics Central continued, this adds additional 45 microseconds to the GPS satellite clocks each day. When the negative 7 microseconds from the special relativity calculation are added, the net result is an additional 38 microseconds.
This implies that engineers must account for an extra 38 microseconds in each satellite’s day in order to maintain the accuracy required to locate your car or phone — or because the system is overseen by the US Department of Defense, a military drone. The onboard atomic clocks do not advance to the next day until they have run for 38 microseconds longer than comparable clocks on Earth. Given those figures, it would take more than seven years for a GPS satellite’s atomic clock to deviate from an Earth clock by more than a blink of an eye. (We did the math: if you assume a blink lasts at least 100,000 microseconds, as the Harvard Database of Useful Biological Numbers does, those 38-microsecond shifts would take thousands of days to accumulate.)
This type of time travel may appear as insignificant as the age difference between the Kelly brothers, but given the hyper-accuracy of modern GPS technology, it does matter. Your phone can pinpoint your exact location in space and time if it can communicate with the satellites flying overhead.
Thank you so much for taking the time to read my article! I hope you enjoyed it and learned something about time travel in the process! If you’d want to discuss something further, provide input, or simply leave a comment, please do so.