In other words, someone in a spacecraft traveling at a high rate of speed will actually have aged less than someone who remained behind on earth (stationary). This is assuming the traveler returns to earth. ie, returns to the same stationary reference frame as he started out. -ETL
In October 1971, Joseph C. Hafele, a physicist, and Richard E. Keating, an astronomer, took four cesium-beam atomic clocks aboard commercial airliners.
They flew twice around the world, first eastward, then westward, and compared the clocks against others that remained at the United States Naval Observatory.
When reunited, the three sets of clocks were found to disagree with one another, and their differences were consistent with the predictions of special and general relativity.
Kinematic time dilation
According to special relativity, the rate of a clock is greatest according to an observer who is at rest with respect to the clock.
In a frame of reference in which the clock is not at rest, the clock runs more slowly, as expressed by the Lorentz factor.
This effect, called time dilation, has been confirmed in many tests of special relativity, such as the Ives–Stilwell experiment and experimental testing of time dilation.[1]
Considering the Hafele–Keating experiment in a frame of reference at rest with respect to the center of the earth, a clock aboard the plane moving eastward, in the direction of the Earth’s rotation, had a greater velocity (resulting in a relative time loss) than one that remained on the ground, while a clock aboard the plane moving westward, against the Earth’s rotation, had a lower velocity than one on the ground.[2]
Gravitational time dilation
General relativity predicts an additional effect, in which an increase in gravitational potential due to altitude speeds the clocks up.
That is, clocks at higher altitude tick faster than clocks on Earth’s surface.
This effect has been confirmed in many tests of general relativity, such as the Pound–Rebka experiment and Gravity Probe A.
In the Hafele–Keating experiment, there was a slight increase in gravitational potential due to altitude that tended to speed the clocks back up.
Since the aircraft flew at roughly the same altitude in both directions, this effect was approximately the same for the two planes, but nevertheless it caused a difference in comparison to the clocks on the ground.[2]
https://en.wikipedia.org/wiki/Hafele%E2%80%93Keating_experiment
Supersize me!
When I was very young my mom took us to Holy Thursday high mass. The experience opened my eyes to many fine things ... including the concept of “infinite”.
Consider for a moment that when you are traveling in a commercial airliner, the pilot and crew are navigating to your destination with the aid of data from the Global Navigation Satellite System (GNSS), of which the United States NAVSTAR Global Positioning System (GPS for short) is the most familiar component.
In fact, “GPS” is often synonymous with satellite navigation, even it is now one of three global satellite navigation systems in operation along with the Russian GLONASS and EU Galileo satellite systems (they will be joined by the Chinese BeiDou-2 system when it expands to global scale in the early 2020s), While this article is specifically about NAVSTAR GPS, the basic operating principles are similar across the various GNSS implementations.
GPS was developed by the United States Department of Defense to provide a satellite-based navigation system for the U.S. military. It was later put under joint DoD and Department of Transportation control to provide for both military and civilian navigation uses, and has become a part of daily life.
Most recent-model cars are equipped with built-in GPS navigation systems (increasingly as standard equipment), you can purchase hand-held GPS navigation units that will give you your position on the Earth (latitude, longitude, and altitude) to an accuracy of 5 to 10 meters that weigh only a few ounces and cost around $100, and GPS technology is increasingly found in smartphones (though not all smartphones derive location information from GPS satellites).
The nominal GPS configuration consists of a network of 24 satellites in high orbits around the Earth, but up to 30 or so satellites may be on station at any given time.
Each satellite in the GPS constellation orbits at an altitude of about 20,000 km from the ground, and has an orbital speed of about 14,000 km/hour (the orbital period is roughly 12 hours - contrary to popular belief, GPS satellites are not in geosynchronous or geostationary orbits). The satellite orbits are distributed so that at least 4 satellites are always visible from any point on the Earth at any given instant (with up to 12 visible at one time). Each satellite carries with it an atomic clock that “ticks” with a nominal accuracy of 1 nanosecond (1 billionth of a second).
A GPS receiver in an airplane determines its current position and course by comparing the time signals it receives from the currently visible GPS satellites (usually 6 to 12) and trilaterating on the known positions of each satellite[1]. The precision achieved is remarkable: even a simple hand-held GPS receiver can determine your absolute position on the surface of the Earth to within 5 to 10 meters in only a few seconds. A GPS receiver in a car can give accurate readings of position, speed, and course in real-time!
More sophisticated techniques, like Differential GPS (DGPS) and Real-Time Kinematic (RTK) methods, deliver centimeter-level positions with a few minutes of measurement. Such methods allow use of GPS and related satellite navigation system data to be used for high-precision surveying, autonomous driving, and other applications requiring greater real-time position accuracy than can be achieved with standard GPS receivers.
To achieve this level of precision, the clock ticks from the GPS satellites must be known to an accuracy of 20-30 nanoseconds. However, because the satellites are constantly moving relative to observers on the Earth, effects predicted by the Special and General theories of Relativity must be taken into account to achieve the desired 20-30 nanosecond accuracy.
Because an observer on the ground sees the satellites in motion relative to them, Special Relativity predicts that we should see their clocks ticking more slowly (see the Special Relativity lecture). Special Relativity predicts that the on-board atomic clocks on the satellites should fall behind clocks on the ground by about 7 microseconds per day because of the slower ticking rate due to the time dilation effect of their relative motion [2].
Further, the satellites are in orbits high above the Earth, where the curvature of spacetime due to the Earth’s mass is less than it is at the Earth’s surface. A prediction of General Relativity is that clocks closer to a massive object will seem to tick more slowly than those located further away (see the Black Holes lecture).
As such, when viewed from the surface of the Earth, the clocks on the satellites appear to be ticking faster than identical clocks on the ground. A calculation using General Relativity predicts that the clocks in each GPS satellite should get ahead of ground-based clocks by 45 microseconds per day.
The combination of these two relativitic effects means that the clocks on-board each satellite should tick faster than identical clocks on the ground by about 38 microseconds per day (45-7=38)! This sounds small, but the high-precision required of the GPS system requires nanosecond accuracy, and 38 microseconds is 38,000 nanoseconds.
If these effects were not properly taken into account, a navigational fix based on the GPS constellation would be false after only 2 minutes, and errors in global positions would continue to accumulate at a rate of about 10 kilometers each day! The whole system would be utterly worthless for navigation in a very short time.
The engineers who designed the GPS system included these relativistic effects when they designed and deployed the system. For example, to counteract the General Relativistic effect once on orbit, the onboard clocks were designed to “tick” at a slower frequency than ground reference clocks, so that once they were in their proper orbit stations their clocks would appear to tick at about the correct rate as compared to the reference atomic clocks at the GPS ground stations.
Further, each GPS receiver has built into it a microcomputer that, in addition to performing the calculation of position using 3D trilateration, will also compute any additional special relativistic timing calculations required [3], using data provided by the satellites.
Relativity is not just some abstract mathematical theory: understanding it is absolutely essential for our global navigation system to work properly.
http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/gps.html
However, if infinite mass is the only requirement, Michael Moore and Rosie O'Donnell could very well be from the future.
Oh, I thought it said infinite ASS.
Noticable with a wrist watch or a calendar, yes. But if tou have two atomic clocks you can notice much smaller changes. I saw a show where scientists syched up two atomic clocks, drove one up a mountain, stayed there overnight and drove back down with it. It was a detectable amount of time off from the other one.
GPS satellites have to be constantly adjusted because of this difference. If not, their error would increase until they were worthless.
Running into any spec of dust at those speeds would be quite a bit more severe than a bug on the windshield......
Nah.
IIRC, FWIW, in the 1960s, the US Navy took two matched Cesium clocks, and put one aloft on a plane for some period of time.
Eventually, the clocks were brought back together, and the one with flight time was behind the one that stayed on the ground.
I think a MIT student, also in the 1960s came up with a theory to travel back in time, but hit the "infinite mass" issue as well.
Went out on a blind date with a woman that had so much mass that it seemed like it took forever for me to get away.
Interesting OP. Thanks.
Yo Mama So FAT....
Time travel is possible as there is a variable missing from Einstein’s equation.
Time is not a function of the speed of light, but is a function of the frequency of consciousness divided by the spped of light.
Consciousness is the most powerful variable in the equation as it is the source of all energy and mass.
You do not need exotic infinite mass to move forward in time.
For forward time travel, we only need to stop our perception of forward travel while we are doing it, and stop, or slow the chemical processes of aging while it is happening.
This is essentially what happens with the Rip Van Winkle legend, and all speculations of suspended animation.
There is no physical law that prevents suspended animation from being achieved. It is essentially a difficult problem in chemical and biological engineering. We do it for short periods with cooling the body while performing some operations.
The hard part of time travel is traveling backward in time. That is a very difficult, maybe impossible, problem.
One would have to change the entire universe, from its present volume to its past, and future volumes.
It won’t happen any time soon.
Since time and space are two forms of energy, & mass and energy are interchangeable, any object or person or mass traveling in a time warp would appear to “float” off the ground to an observer standing nearby, due to the effects of gravity being nullifed in its vertical vector component.
Howsomever, the object in the time warp would appear to move away at the displaced vertical acceleration of gravity which has shifted to the horizontal vector [which has replaced the vertical vector due to the quadruple 90 degree symmetrical gravity/time/space/energy waveforms.] Due to the time warp effecting the vertical gravity vector, the weight of the object would appear to nil. Thus a 300 pound wrestler could be pushed away by your little finger at the acceleration of gravity. The wrestler would appear to the observer to be “frozen in time” as he/she is moving away.
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I already read this tomorrow.
God can see both ends of time and everything in between.....Hmmmmmmmm....
Or, maybe time travel is only a one-way trip. You can travel to the future, but traveling to the past is impossible.
See the time machine in Futurama as a case study.