Today, we know of at least two ways to travel to the future. One relies on cryonic preservation, another, on Einstein's special relativity, the time dilation.
Let's say we want to transfer a terminally ill patient 5 years into the future, because they have reasonable expectations to have effective treatment by then.
With 0.9973582c, we could do it in less than 5 months.
t0 = 12960000 # / 86400 = 150 days v = 299000 c = 299792 t0/(sqrt(1-v^2/c^2)) # / 86400 = 2064.361 days
However, the energy required to accelerate a 50 kg object from rest to this velocity would be:
m = 50 # kg (m*c^2)/(sqrt(1-v^2/c^2)) - m*c^2 # 5.736903e+13 J # = 15935 MWh
We have quite a lot of that energy. A single nuclear power plant may produce that amount of energy in a day. However, in order to use the space technology as medical technology, we would certainly need a efficient way of converting it into kinetic energy...-- Mindey, Mar 21 2016 Time dilation calculator http://keisan.casio...c/system/1224059993 [Mindey, Mar 21 2016] Kinetic energy of relativistic objects https://en.wikipedi...rgy_of_rigid_bodies [Mindey, Mar 21 2016] Joules to MWh http://www.wolframa...736903e%2B13+joules [Mindey, Mar 21 2016] Suspended Animation Suspended_20AnimationI think I'll vote for this method; uses lots less energy and likely could be implemented sooner. [Vernon, Mar 22 2016] Acceleration time > 2 years. http://www.thenaked...s/question/1000139/ [scad mientist, Mar 24 2016] See help file under 'magic'.-- xenzag, Mar 21 2016 I don't think it counts as magic. The idea proposes sending terminally ill people on long journeys at near light-speed, thereby using time dilation to allow medical technology to advance enough to cure them before they die.
The only "magic" component is the last sentence, about harnessing available energy to accelerate the sick person to near light-speed (and to slow them down afterwards, I guess). However, the idea would still stand without that last sentence.
As to the idea - [+]. However, I'd give it more than 5 years; some medical technologies are very slow to develop.-- MaxwellBuchanan, Mar 21 2016 " A single nuclear power plant may produce that amount of energy in a day "
" we would certainly need a efficient way of converting it into kinetic energy "
WIBNI, and certainly preheated in science fiction.-- normzone, Mar 21 2016 //preheated// ummm... cite ?-- FlyingToaster, Mar 21 2016 Since I've not the opportunity to back up the assertion at this time, I will withdraw the preheated.-- normzone, Mar 21 2016 I think that we are somewhat missing the point, which is to use relativity as means of prolonging life pending medical innovation. On the other hand, the Halfbakery has a long and noble tradition of not only missing points, but deliberately aiming off to one side of them, often with unexpected results. So carry on.-- MaxwellBuchanan, Mar 21 2016 Yeah, I tend to take things at face value, which is probably an error in this application. If you just delete the parts of the idea that aren't substantiated it will work fine.-- normzone, Mar 21 2016 [nz] all of the "save later" plans were freezing, that I've read - just wondering.-- FlyingToaster, Mar 21 2016 What was the scifi where all the heads frozen for future cures were cured, installed on robots and used as slaves?-- bungston, Mar 21 2016 Here is scifi premise: the ill ones return to earth but civilization has crashed. In their final months of life, the ill ones use the tech on the ship and their own knowledge to cure thousands from plague and rescue civilization from a dark age.-- bungston, Mar 21 2016 // ... = 15935 MWh // Mindey, you’re using the right formula, but your result is too low by a factor of 10^5. The actual energy is 1,593,599,398 mWh, which is about the same as the world’s yearly electrical output.
You’d need a very advanced space travel system – there are lots of engineering challenges to accelerating something to 0.9973582 c – but you’re right in principle that doing so is a way to travel forward in history at about 13.77 times the normal rate. No magic involved, just good ole century old physics.-- CraigD, Mar 23 2016 /Century old physics/ I have questions.
1. Does time stay slowed for them when they are coming home at the same high velocity they left? I think yes.
2. If #1 is true then if they went in tight circles very fast in our own solar system would time slow? Again I think yes.
3. If they went to the moon (less air resistance, you know) and vibrated back and forth very fast would time slow? It should!
I know the directional changes would be tough on a body. But here is a scheme to reduce that. Imagine I am moving in tight circles at a percentage of the speed of light (and so slowing time for me). Inertia will be perceived by me as a vector force outwards, like gravity: this like the ring-shaped spaceships that use this effect for artificial gravity.
But I am actually moving in 2 circles. Like a planet which both spins and orbits, I am also moving in a larger circle, and even faster than the smaller circle. I complete both circles in the same time. The rotation is timed such that the vector forces of large and small rotations cancel out completely, and I float in zero gravity. Feeling pretty good about myself. Sassy, even.-- bungston, Mar 23 2016 //The rotation is timed such that the vector forces of large and small rotations cancel out completely, and I float in zero gravity.// Isn't this what people sometimes refer to as "an orbit"?-- MaxwellBuchanan, Mar 23 2016 [bungston] If the person is feeling 0 G from that combination of spinning, then they are not accelerating. This means that they are either moving in a straight line or not moving at all.
What we need is a medium-small black hole to orbit around. That has the additional benefit of augmenting the speed based time dilation with gravitational time dilation. The size should be chosen to be as small as possible so it doesn't need to be that far away from our solar system, but it must be large enough that tidal forces are not unmanageable when orbiting close enough to the event horizon to get our desired time dilation. I think it would be most useful to aim for having just enough tidal force that there is 1G force away from the black hole on the far side of the space ship and 1 G towards the black hole in the near side of the ship. Thinking about how wide to make the ship is interesting, but I'm not going to go into details here.
Getting in and out of orbit would require a lot of energy. Ideally this would be set up with well paced objects in orbit that could be used for gravitational slingshots. If they are set up very cleverly, energy is simply exchanged between various objects as ships come and go, resulting on no massive energy usage. I'm not sure that would be possible since you'd probably need to slingshot around black holes to get anywhere close to fast enough. Maybe a system of multiple black holes of various sizes could be made to work.-- scad mientist, Mar 23 2016 Isn't that the idea behind cyrogenics?-- satnavtomington, Mar 23 2016 //Isn't that the idea behind cyrogenics?//
Yes, but the point is that this would work. As yet, we don't know how to freeze a person in such a way that they can be revived.
But relativistic travel would achieve the same result as cryogenics. We could sit down today and design a way to do this, and it would work. We could design a purely chemical rocket that would get you up to 0.9999 C. It would be completely impracticable, but we know it would work.-- MaxwellBuchanan, Mar 23 2016 How long would it take to accelerate to light speed using a traditional rocket?
While a person might withstand 5 Gs for short periods of time, this acceleration will take days so I think we better limit it to 1 G. According to <link> it will take 2 years to get to 0.97c. I hope this is a slow moving disease.
Accelerating with gravitational slingshots is nice because it isn't felt by the person acceleration since all their atoms are accelerated uniformly (except for tidal effects). That could allow you to accelerate much faster.
Another option might be to use diamagnetic levitation in the spacecraft to support passenger during acceleration. It is apparently not harmful to frogs at 1G, but I would worry a little about using it for long periods at a much higher G level. I guess we could test it by building the large superconducting electromagnets needed onto a huge centrifuge so we can use the centrifuge to simulate many Gs, but cancel all but one with the magnet and see if there are any ill effects on test subjects.
Hey, if that works, build a centrifuge ring around the earth... Never mind, it' will take an acceleration of 1.4 Billion g to keep someone in a centrifuge of earth radius at light speed.-- scad mientist, Mar 24 2016 WIFRT I thought of prosciutto.-- pertinax, Mar 25 2016 // 1. Does time stay slowed for them when they are coming home at the same high velocity they left? I think yes. / 2. If #1 is true then if they went in tight circles very fast in our own solar system would time slow? Again I think yes. / 3. If they went to the moon (less air resistance, you know) and vibrated back and forth very fast would time slow? It should! // Yes/yes/yes.
However, for case 3, the force needed to produce noticeable time dilation if far greater than flesh or machine could survive. For case 2, the circle couldn’t be very tight – for example, to experience an force about the same as Earth’s 1 gee surface gravity, the circle would have to have a radius of about 1 light-year (10^16 meters). If it was about the orbit of Pluto, the force would be about 2000 gees, which would reduce a person to goo and separate it into its different cells like a lab centrifuge.-- CraigD, Mar 28 2016 I just had a thought, or at least a puzzlement.
If a person accelerates from standstill to 10m/s in 1 second, they will experience a force of 1g.
However, if they are at 99.9% the speed of light, and accelerate by a further 10m/s in 1 second (as viewed by an outside observer), then it's different. To the outside observer, they will experience 1g. However, they themselves will experience the same delta-v in only a fraction of a second (due to time dilation). So, does this mean that they will subjectively experience a much higher force than 1g?
To put it another way: if someone accelerates at a constant 1g (as viewed by an outside observer), won't they experience a subjectively increasing g-force as they get closer to c?-- MaxwellBuchanan, Mar 28 2016 If spinning counts, does vibration count? Heat is just a form of atomic vibration. If it does, hot things should age slower than cold things on account of their component molecules moving at a greater fraction of the speed of light.
Physicists love nothing more than making very hot things and very cold things, and then writing scholarly papers which contains one entire pageload of author names. Yo pageload! Make something hot and something cold and see if you can tell a difference in aging rate!-- bungston, Mar 28 2016 [bungston] Whereas biological systems are concerned, reduced temperatures slow down metabolic processes and higher temperatures increase metabolic processes.-- MikeD, Mar 28 2016 //If a person accelerates from standstill to 10m/s in 1 second, they will experience a force of 1g. However, if they are at 99.9% the speed of light, and accelerate by a further 10m/s in 1 second (as viewed by an outside observer), then it's different. // No, it’s not.
One of the great beauties of Special Relativity is that it’s built from 2 simple principle: that the laws of physics are the same regardless of your speed; and the speed of light is the same regardless of your speed relative to the light’s source. This means you don’t have to do complicate arithmetic to figure out how nature works for frames with different velocities. It works the same everywhere at every speed.-- CraigD, Mar 28 2016 // If spinning counts, does vibration count? Heat is just a form of atomic vibration. If it does, hot things should age slower than cold things on account of their component molecules moving at a greater fraction of the speed of light.// Yes. Nonzero relative velocity of any kind results in time dilation, but the speeds involved in heat is so small compared to the speed of light that the time dilation is tiny.
For example, if you were made of light stuff like hydrogen and as hot as the core of the Sun, you parts would have an average speed of about 0.0014 c. If you could sustain some sort of biological metabolism at that temperature (rather than getting reduced to your component atoms) you’d age about 31 seconds less per year than a similar organism at room temperature.-- CraigD, Mar 28 2016 Now I'm imagining an organism that lives near black holes and uses time dilatation in part of its life-cycle-- Voice, Mar 28 2016 // A single nuclear power plant may produce that amount of energy in a day. […] we would certainly need a efficient way of converting it into kinetic energy //
Just put the nuclear power plant on the spacecraft. See nuclear rockets (thermal and others).-- notexactly, Mar 30 2016 random, halfbakery