Sci Fi TV science or fiction? |
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Gerinski
Prog Reviewer Joined: February 10 2010 Location: Barcelona Spain Status: Offline Points: 5128 |
Posted: July 29 2013 at 08:26 | ||
I'm not saying it's "true", but how would you break the paradox otherwise? Assuming complete vacuum so light speed is undoubtedly defined, Earth and Sirius do not move at all respect to each other and there's no acceleration / deceleration involved. At the moment you leave Earth, you see Sirius how it was 9 years ago. At the moment you arrive in Sirius, you see Earth how it was 9 years ago. What do you make of it, except that assuming that light has been travelling "just next to you" so you did not "see" any change at all on how does Earth looks like during the trip? |
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Equality 7-2521
Forum Senior Member Joined: August 11 2005 Location: Philly Status: Offline Points: 15783 |
Posted: July 29 2013 at 08:16 | ||
If this were true, then the speed of light in your reference frame would be zero. But the speed of light must be constant in all reference frames. This just doesn't make physical sense. |
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"One had to be a Newton to notice that the moon is falling, when everyone sees that it doesn't fall. "
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Gerinski
Prog Reviewer Joined: February 10 2010 Location: Barcelona Spain Status: Offline Points: 5128 |
Posted: July 29 2013 at 08:09 | ||
The Earth to Sirius example was just to provide some physical case for the thought experiment, you don't need to think that you 'depart' from somewhere and 'arrive' at somewhere else, that instinctively involves some kind of acceleration and deceleration that light (in the vacuum) does simply not require. The effect I was alluding to is that, by definition, if you could travel at the speed of light, light travels at the same speed as you do. Therefore, even if I reckon that this is not a physically sensible question, at any 3-D space point in the trip you would see the same light as you would see anywhere in your past journey at any other 3-D space point. This is somehow the meaning that at c time does not get "experienced", even if surely photons travel through spacetime at a definite speed, they surely visit different 3-D space points, but time is irrelevant because all those 3-D space points are simultaneous from the point of view of the photon. At any rate even if I follow your statement, we may never see ourselves by a septillionth of a second, but we would see a superposition of all the states along the trip which happened a septillionth of a second of our passing through. If we would have been leaving a short 'bread-trail' as Grimm's brothers Little Thumb, we would see it as a superposition of all its states during the trip, just a few septillions delayed from the moment we had left it.
Edited by Gerinski - July 29 2013 at 08:16 |
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Dean
Special Collaborator Retired Admin and Amateur Layabout Joined: May 13 2007 Location: Europe Status: Offline Points: 37575 |
Posted: July 29 2013 at 07:50 | ||
no. The light we see left after us, maybe only a septillionth of a second after, but it left after. At no point in the journey would we ever see ourselves and we would never see ourselves at any point in the journey. The light that left Earth at the same time we did arrived at Sirius at the same time we did, even if you decelerated from c to 0 in 0 seconds, the light travelling with you would have passed before we could see it.
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Gerinski
Prog Reviewer Joined: February 10 2010 Location: Barcelona Spain Status: Offline Points: 5128 |
Posted: July 29 2013 at 06:36 | ||
And at any rate, even admitting that wondering what travelling at the speed of light might 'look like' is physically nonsense and (as far as we can tell today) even a "non-scientific question", when we come to discussing how reasonably sci-fi books or movies depict such situations, it is legitimate to check how far can we get as a thought experiment. For example it is not entirely unacceptable to have a thought such as (following the previous example of Sirius for consistency): Let's say we travel to Sirius, for simplicity let's round its distance from Earth as exactly 9 light years. The Sirius we see from Earth just at the moment of leaving is the Sirius of 9 years ago (Earth or Sirius time assuming for simplicity that Earth and Sirius don't move relative to each other at all). Assuming that we can depart and arrive at light speed without any acceleration / deceleration (as a photon would) and we travel to Sirius at light speed, we will arrive there in 9 years Earth or Sirius time. When we arrive, the Earth we will see from Sirius is the Earth of 9 years ago (Earth or Sirius time). It follows that the Earth we will see on arrival is exactly the same as the Earth we saw on departure. We will see ourselves departing (and consequently since the same applies for any intermediate distance, we will simultaneously see ourselves during the whole trip, from our departure until arrival, somehow we will see a 'superposition of all our trip in a single image'. While this is clearly unphysical for any massive object such as ourselves, there is nothing wrong in the logic itself, it is in accord with Special Relativity. |
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Atavachron
Special Collaborator Honorary Collaborator Joined: September 30 2006 Location: Pearland Status: Online Points: 64636 |
Posted: July 28 2013 at 19:39 | ||
Right. I mostly meant that Spock had explained the principle to the audience, which would make Trek even more science- and physics-savvy than it's given credit for. Not even George Lucas was as astronomically aware as Roddenberry, evidenced by the various slip-ups in his films. |
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Gerinski
Prog Reviewer Joined: February 10 2010 Location: Barcelona Spain Status: Offline Points: 5128 |
Posted: July 28 2013 at 12:33 | ||
Alright I already retracted from that in a later post.
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Equality 7-2521
Forum Senior Member Joined: August 11 2005 Location: Philly Status: Offline Points: 15783 |
Posted: July 28 2013 at 12:00 | ||
What does that have to do with anything? I'm saying that your reference frame at the speed of light is kind of f'd up so it makes little sense to talk about seeing anything within it. |
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"One had to be a Newton to notice that the moon is falling, when everyone sees that it doesn't fall. "
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Dean
Special Collaborator Retired Admin and Amateur Layabout Joined: May 13 2007 Location: Europe Status: Offline Points: 37575 |
Posted: July 28 2013 at 07:12 | ||
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Gerinski
Prog Reviewer Joined: February 10 2010 Location: Barcelona Spain Status: Offline Points: 5128 |
Posted: July 28 2013 at 06:46 | ||
An added issue is that whenever we want to convert mass into energy, only a very small part of the mass can be effectively converted to energy. The only known process which can convert 100% mass into energy is matter - antimatter anihilation. Mass to energy conversion efficiency: Chemical burn: 0.000001% Nuclear Fission: 0.04% Nuclear Fussion: 0.3 ~ 0.5% Accretion disks in massive black holes: 10% Matter – antimatter anihilation: 100% |
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Dean
Special Collaborator Retired Admin and Amateur Layabout Joined: May 13 2007 Location: Europe Status: Offline Points: 37575 |
Posted: July 28 2013 at 06:27 | ||
To date there is no way of resuscitating a cryonically frozen human (legally they have to be dead to be frozen and we cannot reanimate the dead) - at the moment it is no different to ancient Egyptian mummification (and equally as vain IMO). That memory and personality is preserved is pure supposition and without that it is nothing more than food preservation in a deep freeze (the zombies will need feeding ).
No comment: storing personality is no different to transmitting a body with personality intact.
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Dean
Special Collaborator Retired Admin and Amateur Layabout Joined: May 13 2007 Location: Europe Status: Offline Points: 37575 |
Posted: July 28 2013 at 06:12 | ||
Also, with matter to energy to matter transformations the information content remains the same, you stil need to transmit magnitudes in the order of 1028 "bits" of data (based on my previous example) and no compression is possible because there is no redundancy in that information. You could in principle increase the bandwidth and send the data in parallel, but the transmission time saving would only reduce billions of years down to millions of years per human being transported. This is ignoring the time taken to convert the matter to energy and back again, which also would take a finite time dependant on the scanning rate (which like the transmission example, would take billions of years at 1 THz). Not impossible, just impractical and to some extent implausible.
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Gerinski
Prog Reviewer Joined: February 10 2010 Location: Barcelona Spain Status: Offline Points: 5128 |
Posted: July 28 2013 at 06:08 | ||
Since cryonics exist, it's clear that there are people who hope that those difficulties may one day be overcome (as well as people who found a way to make a lot of money from those possibly wrong hopes ). Perhaps the dynamic states could be stored separately from the physical brain atomic state, and once the physical brain has been reconstructed its dynamic state could be re-induced (hey we are just hypothesizing here ).
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Dean
Special Collaborator Retired Admin and Amateur Layabout Joined: May 13 2007 Location: Europe Status: Offline Points: 37575 |
Posted: July 28 2013 at 05:58 | ||
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Gerinski
Prog Reviewer Joined: February 10 2010 Location: Barcelona Spain Status: Offline Points: 5128 |
Posted: July 28 2013 at 05:49 | ||
I think the main problem with this kind of teleportation (analyzing you in full detail, encoding the information and re-assembling an exact copy somewhere else) is that, unless the analyzing step destroys you, and the end of the process there are two of you
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Dean
Special Collaborator Retired Admin and Amateur Layabout Joined: May 13 2007 Location: Europe Status: Offline Points: 37575 |
Posted: July 28 2013 at 05:29 | ||
[another factoid that is relevant to transporting (and cloning) is that idtentical (monozygotic) twins share DNA but are not identical, their fingerprints are different for example, and they have different memories and personalities, it is even possible (though rare) for them to be different sexes]
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Gerinski
Prog Reviewer Joined: February 10 2010 Location: Barcelona Spain Status: Offline Points: 5128 |
Posted: July 28 2013 at 05:25 | ||
And to (hopefully) close the invisibility subject with Friede.
If you define absolute, completely pure invisibility as something not interacting with light at all, not even one photon, then you are right, such a thing would be invisible and blind. Dark matter is believed to not interact electromagnetically at all, photons just cross it without any interaction. In this respect, dark matter is indeed blind. Your misconception comes from taking this literal definition to unnecessary conclusions in a practical sense. It is entirely possible (and common place) to have an intermediate situation where enough of the light crosses so as to make the object or material invisible yet enough of it is absorbed so as to make it able to see. I already gave the example of air, although I admit that an eye made of air would possibly have to be quite big in order to capture the same amount of photons as our eyes. In fact any invisible substances and materials in our world (except dark matter) have this intermediate point, they all surely absorb light so they 'see', but they are nonetheless invisible because they also let enough light through. One thing does not preclude the other.
Edited by Gerinski - July 28 2013 at 05:45 |
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Gerinski
Prog Reviewer Joined: February 10 2010 Location: Barcelona Spain Status: Offline Points: 5128 |
Posted: July 28 2013 at 05:12 | ||
But I guess that some compression techniques should not have any discernible impact on the functional fidelity of the reproduction, I mean, for example we have around 5 liters of blood in our body, but it doesn't matter where precisely each atom is, it's enough to encode "5 liters of blood with the required blood composition (and probably a few more details)" and let it fill the circulatory system, and you don't need to encode a million times how each red cell needs to be, just once x 1,000,000 will do the job.
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Dean
Special Collaborator Retired Admin and Amateur Layabout Joined: May 13 2007 Location: Europe Status: Offline Points: 37575 |
Posted: July 28 2013 at 04:53 | ||
DNA does not describe how the body currently is - simplistically put: it does not contain information on scars, tattoos, hair fashion, body condition (fat, thin, buff, obese, damage, missing parts [tonsils, kidney, digits, limbs, appendix etc], nor does it tell how old the body is, or the contents of the stomach (digestive flora), or the innate and/or adaptive immune system), from DNA you could create a clone embryo but not a perfectly exact adult double. If you reduce the information you reduce the degree by which the copy is an exact copy. So compressed data of the near-exact description of the body as it currently is would also only recreate a near-exact clone not a perfectly exact double.
Because memory and personality do not survive in a resuscitated brain that has been starved of oxygen it is evident that memory and personality are dynamic not static (DRAM not SRAM) - in computing parlance this is like losing your OS on an uncontrolled reboot (rather than just losing the spreadsheet you were working on). To continue the computing analogy (and it is an analogy not a perfect description ) you could clone the PC and reinstall the OS, apps software and data from a back up, but you would not be able to restart the cloned PC in the exact state of the original at the exact moment of switch over (ie with the OS configured, Excel already running and with the exact spreadsheet the user was working on loaded).
Another way of imagining it is as a cloud of intelligentt" gas - each gas molecule is a vector - it has a momentary 3D position, a 3D momentum and a direction (its position, mass, how fast it is going and in what direction). A micrography image of the cloud will only record the 3D position, so if you used that image to recreate a copy of the cloud with each molecule in the exact position of the original but once reanimated they would move off at different velocities and directions to the original. If you took multiple snapshots of the molecules you could calculate the momentum of each one, but your data bit-count has increased. [this is ignoring the observer effect of course].
So with memory and personality because this "information" is dynamic you would need to encode in four dimensions not three, and since it is not simple "momentum" (analogy) but a more complex relationship of events over time, [memory is not the delta between t(n) and t(n-1)] you would need to take more than two snapshots. This is l'esprit d'escalier and the persistence of memory and all those other "thinking" things that differentiate our brain from a USB memory stick and it means that you would probably have to take continuous snapshots going back in time recording all the key events of memory to be able to capture an exact copy of memory and personality, which inevitably would increase the "bit-count" of the data exponentially.
None of these things say that it is theoretically impossible to do, but the volume of data required says the process will take an extraordinary long time to achieve, even with lossless "flac" compression.
Edited by Dean - July 28 2013 at 04:56 |
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Dean
Special Collaborator Retired Admin and Amateur Layabout Joined: May 13 2007 Location: Europe Status: Offline Points: 37575 |
Posted: July 28 2013 at 03:25 | ||
^ it wasn't irrelvant, it was most relevant because it the Romulans had evidently solved the problem (albeit not perfectly in Balance of Terror because the Enterprise was able to track the Bird Of Prey while cloaked). And since the Romulan ships and weapons were not exponentially more powerful it was also evident that they had done it through technology rather than a huge power source.
it is also evident from the comment that Spock is a Science Officer and not an Engneer.
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