Originally posted by twhiteheadWe can test time dilation in a centrifuge. They just built a very large one at CERN.
It works for satellites.
Obviously a train moving fast enough to cause time dilation would be fast enough to fly off the earth like a rocket, so it would have to be held down somehow, but that would be simply a matter of building tracks above it.
I believe that the centripetal effect would have an impact (due to gravity affecting time), but it would cau ...[text shortened]... t time dilation on a centrifuge because we cannot spin them fast enough without if flying apart.
Originally posted by AThousandYoungI'm not overly concern about my limitations if I were moving at the speed of light
There are two different concepts of time being confused here.
Kelly, I agree with you about all sharing a moment in time. However that does not mean we can interact due to the limit of the speed of light. You have to be able to interact to interact! You need to send electromagnetic waves (radio waves, light waves), or make vibrations in the air ( ...[text shortened]... dividuals for millenia in a sort of hibernation for when the world needs heroes and geniuses.
at the moment, and I doubt I ever will be to tell you the truth. 🙂
The changes you experience while moving really fast are not changes in time, again
you may be undergoing changes that does not make time change, the moment
remains the same. You may indeed under go several changes on many levels, that
does not change the moment, only you.
Subjective time that like people's different perspectives? I would suggest that if a
person appeared to age a year that does not mean that time changed around
them, only that they themselves under went some changes that caused them to
appear to age them, again this is different than if time had changed and they did
get a year older in the normal course of time, I'd say less healthy too.
I know it makes for great Science fiction.
Kelly
Originally posted by KazetNagorraI didn't realize that. I suppose it is possible because the fly wheel is so light (single protons or electrons) that it can be contained - yet even so they need massive magnets and an enormous radius to keep it from flying apart.
We can test time dilation in a centrifuge. They just built a very large one at CERN.
What force would be needed to keep a near light speed train from flying off the ground?
Originally posted by twhiteheadOf course building such a device for actual trains would be technically impossible. Current technology already limits us to trains which can get up to speeds of 1000 kph or so, far from the relativistic regime.
I didn't realize that. I suppose it is possible because the fly wheel is so light (single protons or electrons) that it can be contained - yet even so they need massive magnets and an enormous radius to keep it from flying apart.
What force would be needed to keep a near light speed train from flying off the ground?
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Originally posted by KazetNagorraThe first limit is economics not technology. The current land speed record is over 1200km/h which was on flat ground with no rails etc. Presumably with rails we could get a vehicle up to the same speed we can get an aeroplane to which is currently over 3,000km/h. In fact we may even be able to beat that record by removing most of the air from the tunnel and either putting some pure oxygen in (for the jets to use) or driving the vehicle using magnetic propulsion (and magnetic levitation to reduce friction).
Of course building such a device for actual trains would be technically impossible. Current technology already limits us to trains which can get up to speeds of 1000 kph or so, far from the relativistic regime.
From wikipedia:
Manned aircraft: 3,530km/h
Unmanned scramjet: 12,144km/h
Space shuttle on reentry: 28,000km/h
Unless I am mistaken the shuttle achieves nearly 10% of the speed of light. We need to get our train up to about 90% of the speed of light to convince Kelly, because by then time on the train would be nearly half what it is at the station. So we want to get to about 270,000 km/h.
28440km/h is orbital speed at the equator so anything higher than that and we must hold the train down not up.
Originally posted by twhiteheadUnfortuately, were not that close. Light is 300000 km/s not km/h. The shuttle hits .0026 % the speed of light.
The first limit is economics not technology. The current land speed record is over 1200km/h which was on flat ground with no rails etc. Presumably with rails we could get a vehicle up to the same speed we can get an aeroplane to which is currently over 3,000km/h. In fact we may even be able to beat that record by removing most of the air from the tunnel a ...[text shortened]... rbital speed at the equator so anything higher than that and we must hold the train down not up.
Originally posted by amolv06Thanks for the correction. So am I correct that we need to get to over 900,000,000 km/s before we get a time dilation of 2:1 ?
Unfortuately, were not that close. Light is 300000 km/s not km/h. The shuttle hits .0026 % the speed of light.
In looking all this up I came across:
http://metaresearch.org/cosmology/gps-relativity.asp
Which points out that satellites experience two opposite relativistic effects ie time on the satellite moves slower due to its motion and faster due to lower gravity. The difference is the overall effect of relativity, and the results predicted by the theory (a slowing of 7,200ns/day) are observed to within 3%.
Originally posted by KellyJayThe changes you experience while moving really fast are not changes in time, again you may be undergoing changes that does not make time change, the moment remains the same.
I'm not overly concern about my limitations if I were moving at the speed of light
at the moment, and I doubt I ever will be to tell you the truth. 🙂
The changes you experience while moving really fast are not changes in time, again
you may be undergoing changes that does not make time change, the moment
remains the same. You may indeed under go seve ...[text shortened]... ourse of time, I'd say less healthy too.
I know it makes for great Science fiction.
Kelly
This is just a disagreement about which definitions are correct. I don't think you disagree with the basic concept.
The calculations which allow us to precisely predict this phenomenon use a variable called "time". In that sense it is "time changing".
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Originally posted by KellyJaySubjective time that like people's different perspectives? I would suggest that if a person appeared to age a year that does not mean that time changed around them, only that they themselves under went some changes that caused them to
I'm not overly concern about my limitations if I were moving at the speed of light
at the moment, and I doubt I ever will be to tell you the truth. 🙂
The changes you experience while moving really fast are not changes in time, again
you may be undergoing changes that does not make time change, the moment
remains the same. You may indeed under go seve ourse of time, I'd say less healthy too.
I know it makes for great Science fiction.
Kelly
appear to age them, again this is different than if time had changed and they did
get a year older in the normal course of time, I'd say less healthy too.
I should not have used the word "subjective". What happens at relativistic speeds is not subjective. It is objective. However it is localized.
It's not that a person "appears" to age a year. No, they actually live a full year of life in that time and actually age whereas someone at a slower speed would live for a fullt ten productive years and experience ten years of life. It wouldn't be any unhealthier to age ten years in the same time someone else aged one year due to relativistic effects except that old people tend to be less healthy.
If I'm offered a job in space in relativistic velocities, and the travel takes 10 years ship-time and 100 years Earth-time - what is the most fair agreement: 10 years pay or a 100 years pay?
If 10 years pay - is an agreement that I get the money in advance in a bank account be fair?
Originally posted by twhiteheadTo get a time dilation of 2:1 you need a gamma factor of 2, which means you need a velocity of sqrt(3)/2 times the speed of light.
Thanks for the correction. So am I correct that we need to get to over 900,000,000 km/s before we get a time dilation of 2:1 ?
In looking all this up I came across:
http://metaresearch.org/cosmology/gps-relativity.asp
Which points out that satellites experience two opposite relativistic effects ie time on the satellite moves slower due to its motion ...[text shortened]... y, and the results predicted by the theory (a slowing of 7,200ns/day) are observed to within 3%.
Originally posted by FabianFnasPay on such a job would be negotiable and would not be so much about how many years you experience but rather what the overall benefits / disadvantages might be.
If I'm offered a job in space in relativistic velocities, and the travel takes 10 years ship-time and 100 years Earth-time - what is the most fair agreement: 10 years pay or a 100 years pay?
If 10 years pay - is an agreement that I get the money in advance in a bank account be fair?
For example you might look forward to the novelty and there might even be volunteers competing for the job.
On the other hand, you may claim that since you will never see your family again, you deserve a pretty high salary.
Originally posted by twhiteheadYou won't see your immediate family but can see your descendants! I would sure like to see my great great great great grandchildren, see what they are up to!
Pay on such a job would be negotiable and would not be so much about how many years you experience but rather what the overall benefits / disadvantages might be.
For example you might look forward to the novelty and there might even be volunteers competing for the job.
On the other hand, you may claim that since you will never see your family again, you deserve a pretty high salary.
Originally posted by FabianFnasThey'd have to pay you up front and allow you to invest it in the care of your financial representatives. The chance that the same company will exist and have vast amounts of money to pay you with when you get back are low.
If I'm offered a job in space in relativistic velocities, and the travel takes 10 years ship-time and 100 years Earth-time - what is the most fair agreement: 10 years pay or a 100 years pay?
If 10 years pay - is an agreement that I get the money in advance in a bank account be fair?