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AND WHEN TELEPORTATION ARRIVES?

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AND WHEN TELEPORTATION ARRIVES?
Posted by daveklepper on Monday, January 25, 2016 3:36 AM

Imagine transportation 100, 500, or 1000 years from now, assuming Humankind's problems of intolerance and global warming and food and water supplies are solved.  We now have three-dimensional holographic printing.   Imagine this so refined that it can go to the atomic level.  That one can step into a transportation booh and be transported to another booth anywhere else at the speed of light, electronically.  Impossible?  Flying, undersea boats, electric lights, sound and video recording and playback, wired and radio information transmission, and mechanical, non-animal propulsion were once considered impossible.
 
While flying is possible, only the very very rich can afford personal airplanes for transportation.  And while most adult Americans have the use of a personal automobile, most people worldwide do not.  Even those with personal automobiles do not use them for city commuting. So probably only the very rich will have transportation booths in their offices and in their homes for commuting.  Others will use public transportation booths, and costs may rule out use for most for short distances.  So commuter rail and rapid transit trains and light rail will still be around.  Personal automobiles will still be around because teleportation will be too expensive for random short-distance trips, and some people enjoy driving long distances.  Corridor trains will survive for the same reasons as commuter trains and local transportation, but their scope may be reduced in specific markets where the need for teletransportation makes it economical..  But long distance trains will survive for the same reasons they have survived airline development and only if they are pleasant enough to provide a mini-vacation for the traveler.   Airlines?  Possibly not.  Recreational flying, absolutely yes.
Possibly enough people will not trust teleportation for airline survival.
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Posted by Wizlish on Monday, January 25, 2016 4:21 AM

Science fiction alone has done teleportation in as a practical approach, as far as animate objects -- let alone conscious humans -- are concerned.

Effective full-immersion telepresence over the same range, albeit with latency concerns, is 'only' about 750Mbps.  There is the same possibility of degrading QoS in data networks as there is for voice, due to the high assured transmission priority for the packets, but in this case the packets can be packed with full data instead of 'just' reserved for the few bits of compressed voice, so at least theoretically you could 'pad out' low-latency voice transmissions with data of similar latency for another client's telepresence, and have the 'best of both worlds'...

... without the problems teleportation has with re-creating living reality at the other end over an information-based network.  If you solve those issues, we can start dealing with the issues of unintended multiple reception of the information...  George O. Smith had already looked at many of these things back in the '40s.

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Posted by Phoebe Vet on Monday, January 25, 2016 5:34 AM

Heisenberg's Uncertainty Principle says it will not happen.

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Posted by carnej1 on Monday, January 25, 2016 11:35 AM

daveklepper

Imagine transportation 100, 500, or 1000 years from now, assuming Humankind's problems of intolerance and global warming and food and water supplies are solved.  We now have three-dimensional holographic printing.   Imagine this so refined that it can go to the atomic level.  That one can step into a transportation booh and be transported to another booth anywhere else at the speed of light, electronically.  Impossible?  Flying, undersea boats, electric lights, sound and video recording and playback, wired and radio information transmission, and mechanical, non-animal propulsion were once considered impossible.
 
While flying is possible, only the very very rich can afford personal airplanes for transportation.  And while most adult Americans have the use of a personal automobile, most people worldwide do not.  Even those with personal automobiles do not use them for city commuting. So probably only the very rich will have transportation booths in their offices and in their homes for commuting.  Others will use public transportation booths, and costs may rule out use for most for short distances.  So commuter rail and rapid transit trains and light rail will still be around.  Personal automobiles will still be around because teleportation will be too expensive for random short-distance trips, and some people enjoy driving long distances.  Corridor trains will survive for the same reasons as commuter trains and local transportation, but their scope may be reduced in specific markets where the need for teletransportation makes it economical..  But long distance trains will survive for the same reasons they have survived airline development and only if they are pleasant enough to provide a mini-vacation for the traveler.   Airlines?  Possibly not.  Recreational flying, absolutely yes.
Possibly enough people will not trust teleportation for airline survival.
 

Very Larry Niven-esque (read any of his Future History Stories) scenario you describe but if you read up on the actual research into Quantum Teleportation it is not neccesarily going to produce anything remotely Star Trek like in operation. The "3 D printing" based technology you are speculating about would have a little problem with the Heisenberg Uncertainty Principle (which like the Speed of Light is "more than just a suggestion")

 The biggest flaw in trying to predict the future of Humanity thousands of years hence is the fact that we don't know what the nature of Humanity will be at that point (i.e the merging of Man and Machine, REPLACEMENT of Man by said machine, ect..).

 I can also think of plenty of future technological society scenarios that significantly reduce the need to move both people and things en masse, teleportationally or transit-wise..

 

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Posted by daveklepper on Tuesday, January 26, 2016 9:32 AM

I understand the Heisenberg uncertainty principle, and it would have to be solved or resolved, much as the way Relativity resolved the problem of the consistency of the speed of light in two references spaces moving with respect to each other for light omitted in one of the spaces.  Teleportation obviously requires a Universe related to our Einstein-Lorenz-Maxwell-Gauss Relativity Physics Universe the way that Universe is related to the Euclid-Galileo-Carteise-Newton Mechanics Physics Universe.   Philosophically, I have an idea how this can be done.  Imagine some real process of heating or cooling or coloring or lighting or whatever that follows an asymptotic curve.  A mathematician can examine a portion of the curve and then determine the straight line, a quantity or measure vs. time, that the curve approaches but never reaches.  As science progresses, measurements do become more and more accurate, and the measurement process disturbs what is measured less and less.  Turning the philosophical idea into practicality is something obviously for the far future.
 
Here in Jerusalem, Orthodox-run Hotels that usually have "Shabbat Elevators."  But an Orthodox Jew is not supposed to institute or stop any mechanical motion or stop or start any electrical current of any type on Shabbat.  So, obviously, these elevators continually go up and down, stopping at every floor.  But that is not enough.  People getting on and off elevators alter the weight of the elevator and thus change the current drawn.  The solution to this is to make the elevator so heavy that the changes produced by people boarding and leaving are hidden within the random and difficult-to-measure changes produced by variation in friction of the drive system and track.  Possibly applicable to horizontal transportation as well?   (There are more "liberal" Orthodox rabbis who allow a measureable change in electrical current between full load and empty if it is less the 1/60th of the minimum current required to accelerate or brake, based on ruling the if 1/60th the volume of a Kosher drink contains under 1/60th of a non-Kosher, the Kashrut is still valid.
 
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Posted by CMStPnP on Tuesday, January 26, 2016 10:58 AM

I'm one that thinks Teleportation will never happen.    If it was achieveable we would already have more advanced civilizations that were 1,000 of years ahead of us in technology.....teleporting to Earth.

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Posted by dakotafred on Tuesday, January 26, 2016 8:47 PM

I think most business travel, the backbone of the airline industry, is an anachronism that should have disappeared by now, if business weren't stuck in what used to be called "cultural lag." Modern communications is as near as we need to get to teleportation -- yet, business hasn't begun to take advantage.

As for teleportation, the real deal -- after you, Alphonse. Remember "The Fly"!

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Posted by Electroliner 1935 on Tuesday, January 26, 2016 9:34 PM

Teleportation scares me. Does anyone remember the story in playboy and the movie "THE FLY" about the individual who gets in the teleporter and unbeknost to him a fly is also in so when he gets regenerated, he is part fly. Great story. But no thanks. After you Alfonse.

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Posted by daveklepper on Sunday, January 31, 2016 4:34 AM

begin with complex expensive objects, like electron microscopes and tiny ristwatch-computers.  Then plant life.  The mice and fish-in-tanks.   Then trained animals, dogs,horses. Do they rememeger their masters and training?  Then monkeys.   Then the first human voliunteer, with extensive knowledge testing beforfe and after.

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Posted by gregc on Sunday, January 31, 2016 7:02 AM

daveklepper
Imagine transportation 100, 500, or 1000 years from now,

It odd that you suggest there would be any form of physical transportation if teleportation (a la Star Trek) existed.   Why would you need to physically transport either a person or cargo. (Could you teleport to the bottom of an ocean or to the moon)?

And even if teleporation didn't exist, mature 3d-printing may even negate the need to physically transport finished product as long as the raw materials and design information is available as the destination.

Another thing to consider is the need to commute to work.  Remote access to data and processing and conference calls are ubiquitous, negating the need to be in the same room even if in the same building, and I frequently particpate in conference calls with people on the west coast, east coast and Israel.   We typically share a screen but there is no need for video-teleconferencing although that is also available at my workplace.

 

Does "teleporation" actually disassemble an object into particles that are physically relocated to a destination and reassembled?   Or is a replica of the object created at the destination (a la 3d-printing)?   if so, what happens to the original ?? !!

 

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Posted by Firelock76 on Sunday, January 31, 2016 10:50 AM

As an old "Star Trek" fan going back to 1966 let me say the original purpose of the show's "transporter" was to be as a plot device and a time saving measure, i.e. it was used to get the principal actors in and out of various situations without having to go through the trouble (and special effects expense) of showing the starship or a shuttle craft landing on a planet surface, a very real concern at the time since the TV network that bought the show wanted lots of "planet" stories.

However, before they adopted the transporter the shows producers verified that it was theoretically  possible for such a device to exist, though it was a bit of a stretch.  Even though it was science fiction "Star Trek's" producers wanted to keep the show as believeable as possible.  Probably the reason, if not THE reason, it's held up for so long.

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Posted by daveklepper on Monday, February 1, 2016 4:17 AM

gregc

 

 
daveklepper
Imagine transportation 100, 500, or 1000 years from now,

 

It odd that you suggest there would be any form of physical transportation if teleportation (a la Star Trek) existed.   Why would you need to physically transport either a person or cargo. (Could you teleport to the bottom of an ocean or to the moon)?

And even if teleporation didn't exist, mature 3d-printing may even negate the need to physically transport finished product as long as the raw materials and design information is available as the destination.

Another thing to consider is the need to commute to work.  Remote access to data and processing and conference calls are ubiquitous, negating the need to be in the same room even if in the same building, and I frequently particpate in conference calls with people on the west coast, east coast and Israel.   We typically share a screen but there is no need for video-teleconferencing although that is also available at my workplace.

 

Does "teleporation" actually disassemble an object into particles that are physically relocated to a destination and reassembled?   Or is a replica of the object created at the destination (a la 3d-printing)?   if so, what happens to the original ?? !!

 

 

gregc
Does "teleporation" actually disassemble an object into particles that are physically relocated to a destination and reassembled? Or is a replica of the object created at the destination (a la 3d-printing)? if so, what happens to the original ?? !!

I THINK MATTER BECOMES ENERGY BECOMES MATTER     THAT IS THE SIMPLE ANSWER, BUT PROBABLIY THE WHOLE CONCEPT IS ON ANOTHER LEVEL

THAT IS MY GUESS, ANYWAY

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Posted by dakotafred on Monday, February 1, 2016 8:31 AM

gregc
 
daveklepper
Imagine transportation 100, 500, or 1000 years from now,

 

It odd that you suggest there would be any form of physical transportation if teleportation (a la Star Trek) existed.   Why would you need to physically transport either a person or cargo. (Could you teleport to the bottom of an ocean or to the moon)?

And even if teleporation didn't exist, mature 3d-printing may even negate the need to physically transport finished product as long as the raw materials and design information is available as the destination.

Another thing to consider is the need to commute to work.  Remote access to data and processing and conference calls are ubiquitous, negating the need to be in the same room even if in the same building, and I frequently particpate in conference calls with people on the west coast, east coast and Israel.   We typically share a screen but there is no need for video-teleconferencing although that is also available at my workplace.

 

Does "teleporation" actually disassemble an object into particles that are physically relocated to a destination and reassembled?   Or is a replica of the object created at the destination (a la 3d-printing)?   if so, what happens to the original ?? !!

 

 

I address Greg's last paragraph. (Would have reproduced only that on here, but -- old complaint now -- forum mechanics will not let me edit it down.)

From a story I read some time ago in the Wall Street Journal, we're talking disassembly/reassembly, which gives most people pause. (After you, Alphonse.) Calvin and Hobbes, on the other hand, created an all-new person along with survival of the original, or two where there used to be one.

Could make for complications, especially at home.

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Posted by zugmann on Monday, February 1, 2016 9:23 AM

dakotafred
Could make for complications, especially at home.

 

Also was the plot of a Star Trek TNG episode (Second Chances).

It's been fun.  But it isn't much fun anymore.   Signing off for now. 


  

The opinions expressed here represent my own and not those of my employer, any other railroad, company, or person.t fun any

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Posted by gregc on Monday, February 1, 2016 10:10 AM

ive been reading Beyond Our Future in Space which does a very good job discussing specific genes causing some people to have a strong desire to explore which promoted man's migration from Africa and likely to be reason some people wish to leave the Earth.  It covers a lot of history and other topics very concisely.

Today, while reading about propulsion systems, there was actually a section on teleportation (a la Star Trek).   It did report that when a technical advisor to Star Trek was asked how it worked, he said very well (as a time saving device in the TV series).  The book did not attempt to suggest how it might be possible

It did discuss the need to convey the state of 10^28 particles making up a human body and experiments with quantum entanglement to communicate information over long distances.   It did comment on the disassembling/destruction of the body at the origin site and questioned the meaning of "self".

If the mass of the body is converted to energy, E=mc^2 suggests it would be an extremely large amount of energy.     Again I would suggest if it were possible to even identify the composition/state of all the particles in the body, it would be far easier to simply communicate that information to the destination and replicate the body with the ensuing social issues already suggested.

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Posted by Wizlish on Monday, February 1, 2016 10:36 AM

gregc
Again I would suggest if it were possible to even identify the composition/state of all the particles in the body, it would be far easier to simply communicate that information to the destination and replicate the body with the ensuing social issues already suggested.

But there's more to it than just getting all the state numbers correct; you also have a time-defined relationship BETWEEN particles that is not defined by their internal state.  (And which invokes Heisenberg concerns if you perturb anything when determining the numbers...)

So it's simultaneous determination, and then re-creation, of the necessary information for the 10^28 particles ... some of which are moving in several respects relative to others, and together as molecules ... within some reasonably short window of time, with spatial definition of each particle (relative to what reference frame, and how determined?) to some reasonable submultiple of 'effective' interatomic distance.

THEN transfer all this information via quantum entanglement, and implement it physically in the required volume of effective spacetime ... with scaffolding or other equipment 'getting out of the way' of the assembly without perturbing it...

You can't tell me this is going to be cost-effective, any time, anywhere, even absent the safety and quality-assurance concerns...

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Posted by gregc on Monday, February 1, 2016 1:14 PM

Wizlish
You can't tell me this is going to be cost-effective, any time, anywhere, even absent the safety and quality-assurance concerns...

it's just TV

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Posted by Enzoamps on Saturday, February 6, 2016 1:53 AM

I forget the title and author now, but there was a scifi story that focused on the "what to do with the original" question.  The system scanned you, and printed out a new you at the destination.   But that left the original "you" still in existence.  Your original was sedated, then once reception at the other end was verified, they killed the original and broke it down chemically for raw material.

In the story, a problem arose when reception of the duplicate person was not verified right away (stuck in a buffer or something), but the original woke up after the sedation wore off.  The transport operator developed a rellationship with the original, but then a belated, reception OK signal arived, and his dilema was to kill this person he now liked.

Oh, the transporter was licensed alien technology, and NOT killing the original would be an act of war.  Or something...

I suspect that once transporter network is implemented, the dining service will be terrible.

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Posted by Phoebe Vet on Saturday, February 6, 2016 5:59 AM

Enzoamps

I forget the title and author now, but there was a scifi story that focused on the "what to do with the original" question.  The system scanned you, and printed out a new you at the destination.   But that left the original "you" still in existence.  Your original was sedated, then once reception at the other end was verified, they killed the original and broke it down chemically for raw material.

In the story, a problem arose when reception of the duplicate person was not verified right away (stuck in a buffer or something), but the original woke up after the sedation wore off.  The transport operator developed a rellationship with the original, but then a belated, reception OK signal arived, and his dilema was to kill this person he now liked.

Oh, the transporter was licensed alien technology, and NOT killing the original would be an act of war.  Or something...

I suspect that once transporter network is implemented, the dining service will be terribl

 

I saw that episode of "Outer Limits".  

Star trek dealt with the problem by making up a device called a Heisenberg compensator.  You can do anything in science fiction.

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Posted by Deggesty on Saturday, February 6, 2016 7:24 AM

Phoebe Vet

 

 
Enzoamps

I forget the title and author now, but there was a scifi story that focused on the "what to do with the original" question.  The system scanned you, and printed out a new you at the destination.   But that left the original "you" still in existence.  Your original was sedated, then once reception at the other end was verified, they killed the original and broke it down chemically for raw material.

In the story, a problem arose when reception of the duplicate person was not verified right away (stuck in a buffer or something), but the original woke up after the sedation wore off.  The transport operator developed a rellationship with the original, but then a belated, reception OK signal arived, and his dilema was to kill this person he now liked.

Oh, the transporter was licensed alien technology, and NOT killing the original would be an act of war.  Or something...

I suspect that once transporter network is implemented, the dining service will be terribl

 

 

 

I saw that episode of "Outer Limits".  

Star trek dealt with the problem by making up a device called a Heisenberg compensator.  You can do anything in science fiction.

 

Yes, do anything you want--just make it sound reasonable to the casual reader.Smile

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Posted by gregc on Saturday, February 6, 2016 7:57 AM

Deggesty
Yes, do anything you want--just make it sound reasonable to the casual reader.

Some authors, such as Arthur C Clarke, wrote stories where the science was very possible.  He suggested geo-synchrnous satelites but never thought they would become reality in his lifetime.   "The Martian" is a breath of fresh air.

lots of sci-fi asks the "what if" question, both with respect to the science as well as the social ramifications (e.g. John Brunner, "Brave New World").   Isn't this what prompted this thread?

how would a more efficent way of transporting large quantities of goods or people affect railroads?   what would the benefits have to be to make railroad obsolete or change?

could railroads be replaced by ground effect vehicles in the nearer future?

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Posted by Wizlish on Wednesday, February 10, 2016 11:14 AM

gregc
Some authors, such as Arthur C Clarke, wrote stories where the science was very possible. He suggested geo-synchronous satelites but never thought they would become reality in his lifetime.

Well, that's not quite so.  As he himself said, part of his initial objection (circa 1945) was the understanding that the geosynchronous satellites would be manned... and if you are going to that kind of trouble, you might as well be out at L5 or, better, at Venus Equilateral doing reliable interplanetary communication around the Sun.  Miniaturization combined with a better market for EM communication made the geostationary satellite a paying proposition.

... lots of sci-fi asks the "what if" question, both with respect to the science as well as the social ramifications (e.g. John Brunner, "Brave New World"). Isn't this what prompted this thread?

Yes, but lots of SF also asks the 'why?' question, particularly when the technology is excessively involved or dangerous for the results obtained, which prompted the early response to this thread.

We're not discussing TV imitations of teleportation, or 'it's magic' excuses (like handwaving invocations of "hyperdrive" or whatever to implement FTL).  We're talking about actual technology that moves actual things in a manner that is actually cost-effective for the level of service rendered (even if we disregard the rather substantial levels of risk necessarily involved at various levels in the concept).

[quote]How would a more efficient way of transporting large quantities of goods or people affect railroads? what would the benefits have to be to make railroad obsolete or change?

We already have decidedly more achievable examples here.  For passenger service, the medium-range jet and turboprop, and the invention of practicable automobiles, have already demonstrated 'railroad obsolescence' pretty dramatically -- as well as establish where railroads are functionally indispensable.  Freight service has similar examples, albeit often 'non-common-carrier' (like pipelines and long conveyor systems for specific commodities, or better/cheaper water transport, or airplanes for courier and express service)

The current 'game changer' is surely the advance of autonomous vehicle technology, although my opinion is that this is largely NOT dangerous to long-haul freight railroading ... or LD passenger service formatted as an 'experience' and not just point-to-point transportation services.

Teleportation is much more a risk and much more an expense than any simple transportation mode -- including rockets or fancy interstellar propulsion systems (like the one in The Mote in God's Eye).   I can see little point in an instantaneous transportation system when a halfway-decent skip-glide hypersonic transport can achieve the same effect within 54 minutes anywhere (further than about 1000 miles apart) on the Earth's surface, especially when the former is many orders of magnitude more expensive and decidedly uncertain in so many ways.

could railroads be replaced by ground effect vehicles in the nearer future?

This was a Really Big Subject back in the mid-1960s, and I refer you to the 'work product' of the Johnson high-speed rail initiative if you want some examples.  The TL:DR answer is 'no'.  The slightly more extended version is that GEVs involve just as much if not more guideway expense and maintenance criticality as comparable steel-wheel-on-steel-rail systems, for much more fuel expense and noise. 

One idea in the early '60s was that hovercraft 'intermodal' operations would be a benefit -- you could cross the Channel on a (relatively) high-speed turboprop ferry and transition directly to a guideway going to London or other areas.  That is still possible ... if you want large, dedicated swathes of alignment-critical concrete used only by toys for the rich.  They don't involve quite as much of the foundations and civil required for the 'equivalent' multiple-lane highway, but have much, much less alternative use.  The alternative, running over unimproved property, might be interesting for some rural bus services but manifestly not for travel in between cities with any appreciable suburban development.

Hovering vehicles for highway lanes have been tried.  They have all failed for what I consider eminently predictable reasons, much as one would expect that an 'ekranoplan' version for highway lanes would have difficulties not very amenable to engineering solution.

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Posted by blue streak 1 on Saturday, February 13, 2016 4:01 AM

Teleportation not likely but with the first confirmation of gravity waves what could that mean ?  Maybe there will be a way to cancel gravity in certain directions. If earth's gravity could be cancelled a space ship would immediately launch out at its latitude's rotational speed.  Definitely would need a way to meter the cancellation. Of course Newton's law of action and reaction still would hold.

Locomotive applications ?  endless.

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Posted by gregc on Saturday, February 13, 2016 4:07 AM

blue streak 1
Maybe there will be a way to cancel gravity in certain directions.

i thought one of those guys who says he worked in area 51 and has seen the alien spacecraft said that's how these alien space craft work ?!

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Posted by Wizlish on Saturday, February 13, 2016 5:06 AM

blue streak 1
Teleportation not likely but with the first confirmation of gravity waves what could that mean?

Not much ... outside of science fiction.  Note the size of the anomaly needed to confirm the physics.  It is easier to throw a stone in a pond to produce ripples than it is to produce a soliton in the canal at just the right speed for propulsion.

 

Maybe there will be a way to cancel gravity in certain directions. If earth's gravity could be cancelled a space ship would immediately launch out at its latitude's rotational speed.

All you need is a little Cavorite!  (Just keep the canadum propulsion system far, far, far away from me, or my neighborhood!)  But your assumption here exactly negates the one in your following paragraph.  If you 'cancel' gravity, all that happens is that your vehicle STARTS to accelerate away from the Earth at the small rate corresponding to orbital 'correction' for the effective radius of Earth at the latitude involved.  At high latitudes, that is very small indeed.  Of course at the Equator you are moving considerably faster than sound, but your upward 'acceleration' is just a measure of how fast the launch point is rotating away under you as you go straight out, so no major atmospheric effect on the vehicle or dangerous acceleration/jerk at the moment you switch the cancellation on.

A gravity polarizer would be more useful, technically, or one of those extremal black holes that Charlie Stross uses so well.  Although just exactly what you 'cancel' to annul the effect of Earth's 'gravitational field' might be interesting if it also annulled the small changes of relative (vs. 'absolute') motion, some of which IIRC are quite large...

Definitely would need a way to meter the cancellation.

Probably analogous to the method you use to see to navigate a spacecraft flying FTL.  You don't need to modulate the effect, just 'shutter' it (as Wells did, but in quick, short pulses) to get a binary approximation of a continuous (or, come to that, a modulated) thrust.

Of course Newton's law of action and reaction still would hold.

Interesting how the implications differ from those in Doc Smith's inertialess drives, which modulate a different part of the physical system...

Locomotive applications?  endless.

I have been trying to think of one that produces a railroading benefit and am failing, perhaps for lack of the right bold new vision.  About the only one I can come up with is reduction of HAL for overloaded cars, but as you note the inertial force problems would persist. 

Most of the things providing an advantage would modulate gravity higher, not lower: better adhesion on demand; no need for fancy air cylinders on p4s; better prevention of curve tipover ... maybe this is the thing we should study?

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Posted by gregc on Saturday, February 13, 2016 5:54 AM

Wizlish
If you 'cancel' gravity, all that happens is that your vehicle STARTS to accelerate away from the Earth at the small rate corresponding to orbital 'correction' for the effective radius of Earth at the latitude involved.

if you were to be able to cancel the effect of gravity beneath you while on the surface of the Earth, wouldn't you cancel not only the gravity due to the Earth, but also all the gravitational attraction due to the rest (?) of the universe in that direction?    besides centrifical/fugal forces moving you tangentially aware from the Earth?

would it be more effective to wait for alignment with the Sun, allowing its gravity help pull you away from the Earth and then once Earth gravity diminishes, angle a gavity shield toward the Sun?

somewhat like sailing and using the wind.   In this case sailing the local gavity sources.

would the gravity due to the universe in a particular direction be comparable to the force produced by a solar sail?   as well as being constant, not diminishing with distance from the sun?

 

 

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Posted by Wizlish on Saturday, February 13, 2016 6:34 AM

gregc
if you were to be able to cancel the effect of gravity beneath you while on the surface of the Earth, wouldn't you cancel not only the gravity due to the Earth, but also all the gravitational attraction due to the rest (?) of the universe in that direction? besides centrifical/fugal forces moving you tangentially aware from the Earth?

I mentioned that in a different part of the post ... but I don't really think it is an issue if gravity works as it appears to (as a localized distortion of spacetime) rather than as Mach seems to have postulated (as a seemingly comparatively small resultant of very large universal forces).

The effects of acceleration due to the gravity of the Sun are vanishingly small on a vehicle at Earth's radius.  You need to account for them just about as much as you do when correcting things like Hohmann transfer orbits.  (Look at the acceleration needed to maintain the Earth in its orbit with a speed of about, what is it, 66,000 mph but at an AU radius...)

Everything else is much further out at its inverse-square ratio of effectiveness.  Very substantial mass but even more substantial distance.  Added to that, it would appear confirmed that changes in gravitational intensity propagate only at lightspeed, and that they correspond to changes to spacetime distortion associated with very large mass, so there ought to be some analogue to redshift for measured gravitational acceleration due to receding mass (I would not want to have to measure this).

I have been wondering whether the effective gravity from 'the rest of the universe' in a particular direction is similar to the emitted light from 'the rest of the universe' -- much less than some theories expect.  The night sky is black, not bright, and background radiation is very close to zero.  I do think the calculation has been made about when the mass of, say, the Oort cloud exceeds the thrust from the Sun on a solar sail, but I can't tell you what that is (and am too lazy and perhaps too incompetent mathematically to calculate it from available data).  You would be concerned about such a force balance long before the time you'd be 'correcting' solar-sail acceleration for any differential effect of the 'mass of the universe'.

"Sailing" by blocking gravity selectively would be like the inverse of using gravity boosting for probes.  And it would sure be slo-o-o-o-w, and without the moments of screaming terror at perihelion or during aerobraking maneuvers...

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Posted by gregc on Saturday, February 13, 2016 7:01 AM

Wizlish
I have been wondering whether the effective gravity from 'the rest of the universe' in a particular direction is similar to the emitted light from 'the rest of the universe' -- much less than some theories expect.  The night sky is black, not bright, and background radiation is very close to zero. 

is the amount of "dark matter" comparable to the amount of visible light?

Wizlish
"Sailing" by blocking gravity selectively would be like the inverse of using gravity boosting for probes.  And it would sure be slo-o-o-o-w, and without the moments of screaming terror at perihelion or during aerobraking maneuvers...

but unlike sailing, there's no drag and the force is cumulative (i.e. constant acceleration).   And it's always gravity assist ... there's no deceleration when leaving a gravity well ... maybe not so slow

greg - Philadelphia & Reading / Reading

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Posted by Wizlish on Saturday, February 13, 2016 7:52 AM

gregc
is the amount of "dark matter" comparable to the amount of visible light?

I don't know (and wish I did) but I think that in the standard model even the allowance for 'dark matter' doesn't get the cumulative attraction from 'universe' gravity up to a number within many orders of magnitude of local gravitational attraction.  Correct me if wrong.

I also think you are mistaking the numbers for constant boost with the numbers for gravitational attraction.  Remember that there is a LIMITING speed associated with gravitational attraction, which is expressed in part in the formula for escape velocity; by direct implication the highest speed you'd achieve from rest toward Earth by gravitation alone would be about 7 miles per second, which is peanuts by interplanetary standards.  (And a very great deal of that speed is only achieved within a couple of planetary diameters of the surface...).  Even really fast cometary/meteoric incident speeds, boosted by intermediate gravity encounters, are in the peak 40 mps range (convert 'em to metric if you care).

People see numbers like the number of weeks needed to reach relativistic velocity at 1g constant boost, or the velocities achievable with electric or laser propulsion even at milligal (sorry, I like the old expression!) peak acceleration.  Then they think that gravitation has to be better than that because its inverse-square nature means that the acceleration has to be INCREASING the closer in you get.  And it does, which when you remember the limit on achieved speed will tell you just how small the actual acceleration far from masses is.

I reiterate here that your steering authority, if by blocking gravitational attraction, is only 'negative' and therefore pathetically small compared to any ICS or RCS for either trajectory or attitude.  When I said 'sl-o-o-o-w' I meant in terms of time, not necessarily speed, but in terms of distances where non-laser-boosted solar sails make a difference, either metric would apply!

Give me some time and perhaps I can find a way to tie railroading back into this somewhere. 

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Posted by gregc on Saturday, February 13, 2016 8:40 AM

Wizlish
Remember that there is a LIMITING speed associated with gravitational attraction, which is expressed in part in the formula for escape velocity; by direct implication the highest speed you'd achieve from rest toward Earth by gravitation alone would be about 7 miles per second, which is peanuts by interplanetary standards. 

can you explain?

Wizlish
People see numbers like the number of weeks needed to reach relativistic velocity at 1g constant boost, or the velocities achievable with electric or laser propulsion even at milligal (sorry, I like the old expression!) peak acceleration.

I assume conventional gravity assist from the moon would be peanuts compared to the max velocity during the moon maneuver.   But "what if" that max velocity could be maintained because a "gravity shield" limits deceleration when exiting the moon's influence.    Would that be comparable to the velocity of a probe to the outer planets today? (don't compare it to "c").

Would it lessen the time to destination compared to multiple gravity assists around the inner planets and sun? 

Wizlish
Give me some time and perhaps I can find a way to tie railroading back into this somewhere. 

this thread started out as a "what if" ...

greg - Philadelphia & Reading / Reading

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