Time travel
- Thread starter transam
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In this case the clock is fine, it is time going slower. The theory says that's what happens and it happens with every type of clock. You see the same effect, but massively bigger when you start looking at things in space.
Well it does if you're measuring the speed that it moves through local space. Just as the outer edge of a tyre moves faster than the inner bit near the axle.
But yes, time does move slower there. It's an incredibly small difference but it's there.
There's probably a lot of good info out on how it's proven, rather than taking my word for it. Gravity time dilation is the technical term for this.
If it was possible to leave the earth and travel at the speed of light on a space ship for say 5 years?
Than travel back to earth
Would all those people u left behind be dead?
But u would only have aged by 5 years
Than travel back to earth
Would all those people u left behind be dead?
But u would only have aged by 5 years
I don't see how it is measurable on any but the most sophisticated clocks.
You know that's not what was meant. Still once a day.
How do they know that instead of the clock has altered?
Ok.
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Sort of.
Five light years there and back at the speed of light would take five years to travel (as measured on the earth). Then another five years back again. So on earth 10 years would have passed.
For the people on the spaceship only minutes would have passed. So if one of a pair of twins left then when they came back they'd be 10 years younger than the one who stayed.
Of course you can't hit light speed, I'm assuming instant acceleration that'd crush the participants into neutronium and various other things etcthat mean it can't happen. But it's a fun thought experiment.
Ok. Reverse all my questions.Incidentally, I've been getting to the wrong way round. The closer you are to the mass (earth) the slower time passes.
That's right.
Orbiting Satnav clocks run slower. And faster. Net, faster, so they are slowed down.
"When Einstein finalized his theory of gravity and curved spacetime in November 1915, ending a quest which he began with his 1905 special relativity, he had little concern for practical or observable consequences. He was unimpressed when measurements of the bending of starlight in 1919 confirmed his theory. Even today, general relativity plays its main role in the astronomical domain, with its black holes, gravity waves and cosmic big bangs, or in the domain of the ultra-small, where theorists look to unify general relativity with the other interactions, using exotic concepts such as strings and branes.
But GPS is an exception. Built at a cost of over $10 billion mainly for military navigation, GPS has rapidly transformed itself into a thriving commercial industry. The system is based on an array of 24 satellites orbiting the earth, each carrying a precise atomic clock. Using a hand-held GPS receiver which detects radio emissions from any of the satellites which happen to be overhead, users of even moderately priced devices can determine latitude, longitude and altitude to an accuracy which can currently reach 15 meters, and local time to 50 billionths of a second.
But in a relativistic world, things are not simple. The satellite clocks are moving at 14,000 km/hr in orbits that circle the Earth twice per day, much faster than clocks on the surface of the Earth, and Einstein's theory of special relativity says that rapidly moving clocks tick more slowly, by about seven microseconds (millionths of a second) per day.
Also, the orbiting clocks are 20,000 km above the Earth, and experience gravity that is four times weaker than that on the ground. Einstein's general relativity theory says that gravity curves space and time, resulting in a tendency for the orbiting clocks to tick slightly faster, by about 45 microseconds per day. The net result is that time on a GPS satellite clock advances faster than a clock on the ground by about 38 microseconds per day.
To determine its location, the GPS receiver uses the time at which each signal from a satellite was emitted, as determined by the on-board atomic clock and encoded into the signal, together the with speed of light, to calculate the distance between itself and the satellites it communicated with. The orbit of each satellite is known accurately. Given enough satellites, it is a simple problem in Euclidean geometry to compute the receiver's precise location, both in space and time. To achieve a navigation accuracy of 15 meters, time throughout the GPS system must be known to an accuracy of 50 nanoseconds, which simply corresponds to the time required for light to travel 15 meters.
But at 38 microseconds per day, the relativistic offset in the rates of the satellite clocks is so large that, if left uncompensated, it would cause navigational errors that accumulate faster than 10 km per day! GPS accounts for relativity by electronically adjusting the rates of the satellite clocks, and by building mathematical corrections into the computer chips which solve for the user's location. Without the proper application of relativity, GPS would fail in its navigational functions within about 2 minutes."
E
EddieM
Did that on page 5.
He's browsing from the bottom of a very deep well, time moves more slowly down there.
Not really. Stopping time would be something like what you see in science fiction shows where people are frozen and then wake up X years later. Normally expecting it to be a couple of weeks but it turns out to be years! You wouldn't have any experience of the time passing.
Stopping or slowing aging would involve you having more birthdays without losing all your hair.
Stopping or slowing aging would involve you having more birthdays without losing all your hair.
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