Author Topic: Woodward's effect  (Read 284186 times)

Offline flux_capacitor

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Re: Woodward's effect
« Reply #860 on: 04/24/2017 09:42 AM »
Is this "Quantum Handshake" something that lets Mach Effect allow inertial changes to manifest themselves in realtime, rather than having to interact with the distant universe under the limits of lightspeed?

The transactional interpretation of quantum mechanics and Machian relativity theory both share the same "action-at-a-distance" concept described by the Wheeler-Feynman absorber theory. But there is no recognized quantum gravity theory yet: the absorber theory is the only thing they have in common.

According to general relativity with Mach's principle (= gravitational absorber theory) the interaction between an object "here" and the distant matter in the rest of the universe is indeed limited by the speed of light. However, inertial reaction forces are instantaneous. How could that be?

The waves themselves in absorber theory are not superluminal, but the retarded+advanced solutions give a result that appears as being instantaneous. As said earlier, Jim Woodward gave a didactic image how Wheeler-Feynman advanced waves work when applied to gravity and inertia:

A first image to understand would be filming a sequence where a rock is thrown in the middle of a pond, making concentric ripples on the water propagating towards the shore.
Running the sequence backwards (thinking it as seeing events running backward in time) we then observe concentric waves propagating from the shore towards the center of the pond, where a rock emerges.
The thing to understand is that advanced waves coming back from the future never propagate farther into the past than the rock hitting the water that initiated all of the waves.


So when you push on a heavy object, this generates "retarded" inertial reaction waves that propagate forward in time at a limited velocity, interacting with the distant matter in the universe. But a similar "advanced" back reaction field propagates backward in time and reach the object the very instant you touch it, giving its property known as inertia. The retarded and advanced waves are two faces of the same coin, they are connected and time-symmetric like the propagating concentric ripples in the movie of the water pond.
« Last Edit: 04/24/2017 04:25 PM by flux_capacitor »

Offline Mezzenile

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Re: Woodward's effect
« Reply #861 on: 04/24/2017 06:31 PM »
The thing to understand is that advanced waves coming back from the future never propagate farther into the past than the rock hitting the water that initiated all of the waves.
This is not exactly true. In fact, as I have understood, advanced waves coming back from the future do propagate farther into the past than the rock hitting ... But then they cancel with the advanced waves produced by the rock hitting event ...

This cancellation is perfect in an overall flat space, but things may be different in a curved space and this is an open question which could challenge the law of causality. We must stay tune to this strange eventuallity !!  ;) ;)
« Last Edit: 04/24/2017 06:33 PM by Mezzenile »

Online Stormbringer

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Re: Woodward's effect
« Reply #862 on: 04/24/2017 09:40 PM »
challenge the law of causality you say?

https://phys.org/news/2017-04-physicists-violate-local-causality.html

the key in the title is the word "new" as in there are old experiments that show older ways to violate causality.

Causality is the last refuge of hidebound science fuddy-duddies and luddites. ;)

When antigravity is outlawed only outlaws will have antigravity.

Offline flux_capacitor

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Re: Woodward's effect
« Reply #863 on: 04/25/2017 10:01 AM »
The possibility of making time machines depends on the correct interpretation of quantum mechanics. Woodward:

If the Copenhagen or histories/decoherence interpretations of quantum mechanics are right, then time travel, at least to the future, is impossible because the future is in no sense actualized since it is not yet determined.*

If either the deBroglie-Bohm, transactional, or many worlds interpretations of quantum mechanics is correct, then time travel may be in principle possible because reality is deterministic and acausal and the past and future, in some world at least, objectively exist.


* Woodward here evidently poses the problem of a genuine time machine that could "immediately" travel in a far distant future, not the general relativity trick consisting of travelling during a long time at a relativistic velocity in a spaceship then returning to Earth, which would indeed be time travel into the future.
« Last Edit: 04/25/2017 12:50 PM by flux_capacitor »

Offline flux_capacitor

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Re: Woodward's effect
« Reply #864 on: 04/25/2017 12:55 PM »
The thing to understand is that advanced waves coming back from the future never propagate farther into the past than the rock hitting the water that initiated all of the waves.
This is not exactly true. In fact, as I have understood, advanced waves coming back from the future do propagate farther into the past than the rock hitting ... But then they cancel with the advanced waves produced by the rock hitting event ...

This cancellation is perfect in an overall flat space, but things may be different in a curved space and this is an open question which could challenge the law of causality. We must stay tune to this strange eventuallity !!  ;) ;)

What is the physical meaning of a wave that is "cancelled out" at some point but still "propagating" beyond this point? Seems to me as the ending spacetime point for this wave.

Offline dustinthewind

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Re: Woodward's effect
« Reply #865 on: 04/27/2017 04:40 PM »
Is this "Quantum Handshake" something that lets Mach Effect allow inertial changes to manifest themselves in realtime, rather than having to interact with the distant universe under the limits of lightspeed?

The transactional interpretation of quantum mechanics and Machian relativity theory both share the same "action-at-a-distance" concept described by the Wheeler-Feynman absorber theory. But there is no recognized quantum gravity theory yet: the absorber theory is the only thing they have in common.

According to general relativity with Mach's principle (= gravitational absorber theory) the interaction between an object "here" and the distant matter in the rest of the universe is indeed limited by the speed of light. However, inertial reaction forces are instantaneous. How could that be?

The waves themselves in absorber theory are not superluminal, but the retarded+advanced solutions give a result that appears as being instantaneous. As said earlier, Jim Woodward gave a didactic image how Wheeler-Feynman advanced waves work when applied to gravity and inertia:

A first image to understand would be filming a sequence where a rock is thrown in the middle of a pond, making concentric ripples on the water propagating towards the shore.
Running the sequence backwards (thinking it as seeing events running backward in time) we then observe concentric waves propagating from the shore towards the center of the pond, where a rock emerges.
The thing to understand is that advanced waves coming back from the future never propagate farther into the past than the rock hitting the water that initiated all of the waves.


So when you push on a heavy object, this generates "retarded" inertial reaction waves that propagate forward in time at a limited velocity, interacting with the distant matter in the universe. But a similar "advanced" back reaction field propagates backward in time and reach the object the very instant you touch it, giving its property known as inertia. The retarded and advanced waves are two faces of the same coin, they are connected and time-symmetric like the propagating concentric ripples in the movie of the water pond.

I think it may be possible that quantum superpositions are multiple probabilities that exist in the time line in which we exist.  The collapse of a quantum probability to an actual event then concludes the path of our future.  In that sense for that to happen it may be necessary for signals to travel back in time to conclude the result of those multiple possibilities. 

Offline M.E.T.

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Re: Woodward's effect
« Reply #866 on: 04/29/2017 02:41 PM »
Suppose the Mach Effect proves real and a viable space propulsion mechanism. Let's say it can eventually provide continuous thrust of 1G over the duration of an interstellar voyage - say to Alpha Centauri.

Let's further say that it comes into regular use, and hundreds or even thousands of MET drive ships are in operation by mankind. So, you have ships continously accelerating up to say 95% the speed of light and then beginning a deceleration halfway into the voyage, in order to arrive at their destinations at a dead stop.

Now, what happens when the Thruster breaks down on a particular ship halfway into its return journey to Earth, meaning the ship can no longer decelerate, leaving it travelling to its destination at 95% the speed of light. The idea being that you now have a relativistic missile heading straight for the Earth. If the ship is say several hundred meters across, weighing thousands of tons, well, you get the idea.

My concern being, could the achievement of such a space drive be a kind of answer to the Fermi paradox? Meaning you only need one such ship to malfunction and strike your home planet to create a catastrophic outcome?

And given this danger, are there some standard safety mechanisms that can be adopted if such a technology is in widespread use, to minimize this risk? Like self destruct mechanisms, or perhaps protocols to never head straight to a destination, but instead only change course directly for your destination planet once you have reached the inner solar system, and your velocity is significantly lower?

Else the Mach Effect could prove an existential threat to our species, if proven true.

Offline flux_capacitor

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Re: Woodward's effect
« Reply #867 on: 04/29/2017 03:02 PM »
Suppose the Mach Effect proves real and a viable space propulsion mechanism. Let's say it can eventually provide continuous thrust of 1G over the duration of an interstellar voyage - say to Alpha Centauri.

Let's further say that it comes into regular use, and hundreds or even thousands of MET drive ships are in operation by mankind. So, you have ships continously accelerating up to say 95% the speed of light and then beginning a deceleration halfway into the voyage, in order to arrive at their destinations at a dead stop.

Now, what happens when the Thruster breaks down on a particular ship halfway into its return journey to Earth, meaning the ship can no longer decelerate, leaving it travelling to its destination at 95% the speed of light. The idea being that you now have a relativistic missile heading straight for the Earth. If the ship is say several hundred meters across, weighing thousands of tons, well, you get the idea.

My concern being, could the achievement of such a space drive be a kind of answer to the Fermi paradox? Meaning you only need one such ship to malfunction and strike your home planet to create a catastrophic outcome?

And given this danger, are there some standard safety mechanisms that can be adopted if such a technology is in widespread use, to minimize this risk? Like self destruct mechanisms, or perhaps protocols to never head straight to a destination, but instead only change course directly for your destination planet once you have reached the inner solar system, and your velocity is significantly lower?

Else the Mach Effect could prove an existential threat to our species, if proven true.

Planets orbit their star. If a ship several light-years away travelling at 95% c towards the solar system does not decelerate, there is virtually no chance it would collide with the Sun, the Earth or any other planet. Watch this video giving relative distances between planetary bodies. The ship, travelling almost along a straight line, would be smaller than a sand grain:



However, I do see your point about an insane dictator trying to obliterate the Earth with an RKKV.

Offline M.E.T.

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Re: Woodward's effect
« Reply #868 on: 04/29/2017 03:13 PM »
So you are saying that no voyage would ever plot a direct line course from LEO of its departure planet to LEO of its destination planet in a neighbouring solar system? Instead, they would just aim roughly for the star in question and then refine their course once passing through the Kuiper belt of the destination system, for example?

Offline tchernik

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Re: Woodward's effect
« Reply #869 on: 04/29/2017 03:59 PM »

Else the Mach Effect could prove an existential threat to our species, if proven true.

I'm more concerned about someone intentionally aiming a piece of junk with a MET attached without anyone noticing. There is no shortage of disgruntled, unhappy or crazy people around, and any of them can one day decide life is not worth living, deciding to turn the lights off for everyone else too; sending out an improvised kinetic missile or subverting an existing one (like a ship, as some pilots have unfortunately done) and then bring it back to Earth at full steam for a date with history.

METs (and Emdrives, any space drive really) would make very easy to make terrifying kinetic impactors.

If they exist, they would really need to be regulated more than nuclear weapons.
« Last Edit: 04/29/2017 04:00 PM by tchernik »

Offline LowerAtmosphere

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Re: Woodward's effect
« Reply #870 on: 04/29/2017 11:28 PM »
The thing to understand is that advanced waves coming back from the future never propagate farther into the past than the rock hitting the water that initiated all of the waves.
This is not exactly true. In fact, as I have understood, advanced waves coming back from the future do propagate farther into the past than the rock hitting ... But then they cancel with the advanced waves produced by the rock hitting event ...

This cancellation is perfect in an overall flat space, but things may be different in a curved space and this is an open question which could challenge the law of causality. We must stay tune to this strange eventuallity !!  ;) ;)

Yes indeed these are exciting times, through the timeline violation of the superluminal Alcubierre concept we have a posssibility which seems so much more alluring, even if we stick to travelling forwards.
https://phys.org/news/2017-04-math-possibility.html

Offline LowerAtmosphere

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Re: Woodward's effect
« Reply #871 on: 04/29/2017 11:32 PM »
Suppose the Mach Effect proves real and a viable space propulsion mechanism. Let's say it can eventually provide continuous thrust of 1G over the duration of an interstellar voyage - say to Alpha Centauri.

Let's further say that it comes into regular use, and hundreds or even thousands of MET drive ships are in operation by mankind. So, you have ships continously accelerating up to say 95% the speed of light and then beginning a deceleration halfway into the voyage, in order to arrive at their destinations at a dead stop.

Now, what happens when the Thruster breaks down on a particular ship halfway into its return journey to Earth, meaning the ship can no longer decelerate, leaving it travelling to its destination at 95% the speed of light. The idea being that you now have a relativistic missile heading straight for the Earth. If the ship is say several hundred meters across, weighing thousands of tons, well, you get the idea.

My concern being, could the achievement of such a space drive be a kind of answer to the Fermi paradox? Meaning you only need one such ship to malfunction and strike your home planet to create a catastrophic outcome?

And given this danger, are there some standard safety mechanisms that can be adopted if such a technology is in widespread use, to minimize this risk? Like self destruct mechanisms, or perhaps protocols to never head straight to a destination, but instead only change course directly for your destination planet once you have reached the inner solar system, and your velocity is significantly lower?

Else the Mach Effect could prove an existential threat to our species, if proven true.
There's no way such orbital precision is possible if delta-v is altered so little. Maneuvers planned in advance always utilize the orbital calculations needed for target lock on and then deorbiting. It will simply overshoot as space is massive and there really aren't too many gravity wells affecting the missile. No protocols needed, just basic astronomy and orbital mechanics.

Edit: Should also clarify that advanced maneuvers and flight command chains exist to decelerate crafts by bouncing on atmospheres or losing inertia to planets and other gravitating objects.
« Last Edit: 04/29/2017 11:37 PM by LowerAtmosphere »

Offline Bynaus

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Re: Woodward's effect
« Reply #872 on: 05/01/2017 12:37 PM »

Else the Mach Effect could prove an existential threat to our species, if proven true.

I'm more concerned about someone intentionally aiming a piece of junk with a MET attached without anyone noticing. There is no shortage of disgruntled, unhappy or crazy people around, and any of them can one day decide life is not worth living, deciding to turn the lights off for everyone else too; sending out an improvised kinetic missile or subverting an existing one (like a ship, as some pilots have unfortunately done) and then bring it back to Earth at full steam for a date with history.

METs (and Emdrives, any space drive really) would make very easy to make terrifying kinetic impactors.

If they exist, they would really need to be regulated more than nuclear weapons.

This is true and, I think, completely underapprecciated today. If Mach drives exist, everybody having their hands on one will also have the possibility, in principle, of inflicting a nuclear-explosion-level damage (even much more) on any point on the Earth's (or any other planets, moons or asteroids) surface. Nothing would keep, e.g., Kim Jong-Un to hide a few impactors somewhere in the Kuiper belt, ready to accelerate and strike any point in the US whenever needed (they might need a few weeks to reach Earth, but that wouldn't reduce much the damage they could do once unleashed). To mitigate against that type of threat, it might (eventually) become necessary to constantly scan the vicinity of the Earth for relativistic impactors, and have a fleet of ultra-fast accelerating Mach drive missiles ready to intercept (remember that at ~c, a kinetic impactor would cross the Earth-Moon distance in 1 sec... So this would require scanning for sub-meter-sized objects several light-seconds out or even further - difficult, but probably not impossible). Lasers won't help here either because you have to make sure the bulk mass of the impactor doesn't hit the atmosphere - whether it reaches the atmosphere in a solid, molten or vaporized state makes (almost) no difference. Alternatively, you just have to make sure you live in a place where your future position cannot easily be determined. I.e., if we all lived in space colonies attached to randomly firing Mach drives, the threat of such impactors might be mitigated, too. So yes, I see this outcome as a possible solution to the Fermi paradox: Only those civilizations who do not yet know of the terror of relativistic impactors freely share their position with others...

Offline birchoff

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Re: Woodward's effect
« Reply #873 on: 05/02/2017 03:05 AM »

Else the Mach Effect could prove an existential threat to our species, if proven true.

I'm more concerned about someone intentionally aiming a piece of junk with a MET attached without anyone noticing. There is no shortage of disgruntled, unhappy or crazy people around, and any of them can one day decide life is not worth living, deciding to turn the lights off for everyone else too; sending out an improvised kinetic missile or subverting an existing one (like a ship, as some pilots have unfortunately done) and then bring it back to Earth at full steam for a date with history.

METs (and Emdrives, any space drive really) would make very easy to make terrifying kinetic impactors.

If they exist, they would really need to be regulated more than nuclear weapons.

This is true and, I think, completely underapprecciated today. If Mach drives exist, everybody having their hands on one will also have the possibility, in principle, of inflicting a nuclear-explosion-level damage (even much more) on any point on the Earth's (or any other planets, moons or asteroids) surface. Nothing would keep, e.g., Kim Jong-Un to hide a few impactors somewhere in the Kuiper belt, ready to accelerate and strike any point in the US whenever needed (they might need a few weeks to reach Earth, but that wouldn't reduce much the damage they could do once unleashed). To mitigate against that type of threat, it might (eventually) become necessary to constantly scan the vicinity of the Earth for relativistic impactors, and have a fleet of ultra-fast accelerating Mach drive missiles ready to intercept (remember that at ~c, a kinetic impactor would cross the Earth-Moon distance in 1 sec... So this would require scanning for sub-meter-sized objects several light-seconds out or even further - difficult, but probably not impossible). Lasers won't help here either because you have to make sure the bulk mass of the impactor doesn't hit the atmosphere - whether it reaches the atmosphere in a solid, molten or vaporized state makes (almost) no difference. Alternatively, you just have to make sure you live in a place where your future position cannot easily be determined. I.e., if we all lived in space colonies attached to randomly firing Mach drives, the threat of such impactors might be mitigated, too. So yes, I see this outcome as a possible solution to the Fermi paradox: Only those civilizations who do not yet know of the terror of relativistic impactors freely share their position with others...

Really... first off I dont disagree with the opinion that relitavistic weaponery would become a thing. But how does humanity gain access to a MET capable of heavy lift (constant 1g+) and remain prisoner to the idiots around us. I mean really. If MET's can be scalled to constant 1g+ thrust. Then  cleaning up LEO and GEO becomes cheap. I can only imagine the amount of money that could be made by simply recycling dead sats in those orbits. Take that money and build a fleet of high resolution space telescopes that can survey the entire sky in a number of spectrums. That fleet would pay for itself; why? because it would put all if not most terrestrial telescopes out of business. Especially if it is paired with high bandwidth laser/maser communications. Two steps and you have protected earth from relativistic weapons.

But why stop there if you have 1g+ thrust. Then why cant we dispose of fission waste in the sun or take it repurpose it as a heat generator on the moon or mars. That business would print money...

If you have 1g+ thrust. Then space tourism becomes a thing. granted we would need to throw some money at artificial gravity for space stations and much better space suits. But we no longer have to completely bootstrap industry off the planet. You can build everything on the planet and lift it off the planet. The cost reduction would be startling.

if you have 1g+ thrust terraforming mars or providing an atmosphere for stations becomes trivial (suck it out of venus' atmosphere and separate it)

I left out space mining... but that's only because I feel that is obvious. My point is the upside of 1g+ MET means you don't have to restrict the technology. just simply throw money at developing its other uses. 

Oh yeah, most of the damage you guys are talking about can be had by simply putting kinetic impactors in orbit.

Offline tchernik

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Re: Woodward's effect
« Reply #874 on: 05/02/2017 05:22 AM »

This is true and, I think, completely underapprecciated today. If Mach drives exist, everybody having their hands on one will also have the possibility, in principle, of inflicting a nuclear-explosion-level damage (even much more) on any point on the Earth's (or any other planets, moons or asteroids) surface. Nothing would keep, e.g., Kim Jong-Un to hide a few impactors somewhere in the Kuiper belt, ready to accelerate and strike any point in the US whenever needed (they might need a few weeks to reach Earth, but that wouldn't reduce much the damage they could do once unleashed). To mitigate against that type of threat, it might (eventually) become necessary to constantly scan the vicinity of the Earth for relativistic impactors, and have a fleet of ultra-fast accelerating Mach drive missiles ready to intercept (remember that at ~c, a kinetic impactor would cross the Earth-Moon distance in 1 sec... So this would require scanning for sub-meter-sized objects several light-seconds out or even further - difficult, but probably not impossible). Lasers won't help here either because you have to make sure the bulk mass of the impactor doesn't hit the atmosphere - whether it reaches the atmosphere in a solid, molten or vaporized state makes (almost) no difference. Alternatively, you just have to make sure you live in a place where your future position cannot easily be determined. I.e., if we all lived in space colonies attached to randomly firing Mach drives, the threat of such impactors might be mitigated, too. So yes, I see this outcome as a possible solution to the Fermi paradox: Only those civilizations who do not yet know of the terror of relativistic impactors freely share their position with others...

The only long term solution for this that occurs to me, is to plan a deliberate diaspora of humans into space settlements and asteroids as soon as the technology and science of METs is confirmed, and launch ships and habitats as soon as it is possible, for developing what's needed to take those settlements as far as they can from the risky planets, deep into the Kuiper belt and beyond, with the explicit purpose of eventually getting off the radar.

If position and visibility become a risk, the solution is to hide, make backups and expand.

Of course, it is doubtful Earth could never be fully evacuated in any meaningful time frame, therefore a parallel state machinery of surveillance and tight regulation of the METs would emerge (the same as with nuclear power), where every single private MET thruster is accounted for, tracked and could be remotely disabled. And probably within some radius of Earth, no object would be allowed to move above certain speeds or follow an accelerating trajectory of more than certain fractions of G.

It is in fact very likely, that the attempts to safeguard Earth vs the abuses would collide with the plans of leaving it, given both rely on controlling a tech that would be at the root of these future problems. But no government control is airtight, and there are more than one government on Earth, giving the diaspora a chance to actually happen.

Also, my apologies if this discussion seems to be eccentric and premature, but the enthusiasm of these potential scientific discoveries being true, should also be tempered by the unavoidable reality that any knowledge, specially one so powerful in energies as this, can be used for ill as much as for good.

We are in very peculiar times, when these things have ceased to be complete speculations and start knocking at the door of possibility, however remote that may be.
« Last Edit: 05/02/2017 05:33 AM by tchernik »

Offline Bynaus

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Re: Woodward's effect
« Reply #875 on: 05/02/2017 06:30 AM »
First this:

Quote from: birchoff
Oh yeah, most of the damage you guys are talking about can be had by simply putting kinetic impactors in orbit.

Nope. In orbit, kinetic energy is 60 Megajoules per kg. A relativistic kinetic impactor can easily get 60 Megatons per kg...

Quote
But how does humanity gain access to a MET capable of heavy lift (constant 1g+) and remain prisoner to the idiots around us.

Well, how did humanity get access to fusion bombs and remain prisoner to the same idiots? Humans will always be humans, regardless of technology.

All the technological developments you mention would probably happen, but wouldn't defuse the threat of relativistic weaponry. Just having telescopes looking out for relativistic kinetic impactors (RKIs) will not protect the Earth alone - as mentioned, you need some kind of interceptor which can build up in very short time the kinetic energy needed to divert the RKI from its collision path (or at least deviate it such that it doesn't hit a city and impacts over the ocean instead - if that is enough...). To do that, you need to find the approaching RKI, calculate its trajectory, notify a battery of interceptors, launch them and have them reach the RKI in time, all in the matter of a few seconds...

One limitation to the RKI threat is probably that the acceleration to relativistic speeds is energy-limited, and therefore you would also need a very powerful energy source to build an RKI (also, as a consequence the RKI would probably glow brightly - at least in infrared - on approach, which makes it easier to identify - unless you accelerate it from very far away so it has time to cool down again). But in a future where both Mach drives and compact nuclear fusion are commonplace, at least state actors should have no problem setting up a fleet of RKIs in the Kuiper belt or beyond.

Quote from: tchernik
If position and visibility become a risk, the solution is to hide, make backups and expand.

Exactly.

Quote
Of course, it is doubtful Earth could never be fully evacuated in any meaningful time frame, therefore a parallel state machinery of surveillance and tight regulation of the METs would emerge (the same as with nuclear power), where every single private MET thruster is accounted for, tracked and could be remotely disabled. And probably within some radius of Earth, no object would be allowed to move above certain speeds or follow an accelerating trajectory of more than certain fractions of G.

That radius would have to be very big (probably encompass the solar system or so) to make sure any rogue Mach drives could be intercepted in time. But then, how would you track those who do not want to be tracked? As long as you have different states with different interests, surveillance / regulation will always serve the needs of these interests.

So I agree - the diaspora would be likely to happen. On these ships going into hiding/riding, you can even have a comfy 1 Ge - just accelerate constantly with your Mach drive (but not in a fully deterministic fashion). Go see the universe. All you need is something to feed your fusion reactor with, but that, you can get from everywhere. And hey, at 1 Ge acceleration, the next star system is only a few years of travel away. That's certainly doable, right? And while we're at it: the galactic center is only 30 years away, 60 if you want to stop...
« Last Edit: 05/02/2017 06:31 AM by Bynaus »

Offline birchoff

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Re: Woodward's effect
« Reply #876 on: 05/02/2017 02:11 PM »
First this:

Quote from: birchoff
Oh yeah, most of the damage you guys are talking about can be had by simply putting kinetic impactors in orbit.

Nope. In orbit, kinetic energy is 60 Megajoules per kg. A relativistic kinetic impactor can easily get 60 Megatons per kg...

Quote
But how does humanity gain access to a MET capable of heavy lift (constant 1g+) and remain prisoner to the idiots around us.

Well, how did humanity get access to fusion bombs and remain prisoner to the same idiots? Humans will always be humans, regardless of technology.

All the technological developments you mention would probably happen, but wouldn't defuse the threat of relativistic weaponry. Just having telescopes looking out for relativistic kinetic impactors (RKIs) will not protect the Earth alone - as mentioned, you need some kind of interceptor which can build up in very short time the kinetic energy needed to divert the RKI from its collision path (or at least deviate it such that it doesn't hit a city and impacts over the ocean instead - if that is enough...). To do that, you need to find the approaching RKI, calculate its trajectory, notify a battery of interceptors, launch them and have them reach the RKI in time, all in the matter of a few seconds...

One limitation to the RKI threat is probably that the acceleration to relativistic speeds is energy-limited, and therefore you would also need a very powerful energy source to build an RKI (also, as a consequence the RKI would probably glow brightly - at least in infrared - on approach, which makes it easier to identify - unless you accelerate it from very far away so it has time to cool down again). But in a future where both Mach drives and compact nuclear fusion are commonplace, at least state actors should have no problem setting up a fleet of RKIs in the Kuiper belt or beyond.

Quote from: tchernik
If position and visibility become a risk, the solution is to hide, make backups and expand.

Exactly.

Quote
Of course, it is doubtful Earth could never be fully evacuated in any meaningful time frame, therefore a parallel state machinery of surveillance and tight regulation of the METs would emerge (the same as with nuclear power), where every single private MET thruster is accounted for, tracked and could be remotely disabled. And probably within some radius of Earth, no object would be allowed to move above certain speeds or follow an accelerating trajectory of more than certain fractions of G.

That radius would have to be very big (probably encompass the solar system or so) to make sure any rogue Mach drives could be intercepted in time. But then, how would you track those who do not want to be tracked? As long as you have different states with different interests, surveillance / regulation will always serve the needs of these interests.

So I agree - the diaspora would be likely to happen. On these ships going into hiding/riding, you can even have a comfy 1 Ge - just accelerate constantly with your Mach drive (but not in a fully deterministic fashion). Go see the universe. All you need is something to feed your fusion reactor with, but that, you can get from everywhere. And hey, at 1 Ge acceleration, the next star system is only a few years of travel away. That's certainly doable, right? And while we're at it: the galactic center is only 30 years away, 60 if you want to stop...

your missing my point. The reason we have to restrict access to fusion/fission bombs is because WE HAVE BUT ONE  PLANET. and that weaponry can destroy the one planet we have. Heavy Lift MET's basically remove the biggest barrier to humanity only having a single planet it can live on. Heavy Lift MET's  will basically lead us to moving off planet. There are other technologies we need. but it is my position that those technologies do not see alot of investment because the market doesnt believe there is a need. heavy lift MET's would automatically generate a market need while providing the buyers with a variety of business opportunities to fund development/procurement of that need. That means at most their would be a short term threat. but long term humanity would be sufficiently spread out across the inner and possibly outer solar system than relativistic impactors just become a nice way to piss off people. instead of being the end of humanity scenario it is today.

One other thing I forgot to mention. heavy lift met's also provide you with a protection system. if you have complete coverage of the sky to detect them. then you just need a drone pulling  many many G's of constant acceleration to pull up along side and alter its course. Or take the SPS system and use it to power a GW Laser. again relativistic impactors are not a great concern here

Offline Bynaus

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Re: Woodward's effect
« Reply #877 on: 05/02/2017 02:49 PM »
First this:

Quote from: birchoff
Oh yeah, most of the damage you guys are talking about can be had by simply putting kinetic impactors in orbit.

Nope. In orbit, kinetic energy is 60 Megajoules per kg. A relativistic kinetic impactor can easily get 60 Megatons per kg...

Quote
But how does humanity gain access to a MET capable of heavy lift (constant 1g+) and remain prisoner to the idiots around us.

Well, how did humanity get access to fusion bombs and remain prisoner to the same idiots? Humans will always be humans, regardless of technology.

All the technological developments you mention would probably happen, but wouldn't defuse the threat of relativistic weaponry. Just having telescopes looking out for relativistic kinetic impactors (RKIs) will not protect the Earth alone - as mentioned, you need some kind of interceptor which can build up in very short time the kinetic energy needed to divert the RKI from its collision path (or at least deviate it such that it doesn't hit a city and impacts over the ocean instead - if that is enough...). To do that, you need to find the approaching RKI, calculate its trajectory, notify a battery of interceptors, launch them and have them reach the RKI in time, all in the matter of a few seconds...

One limitation to the RKI threat is probably that the acceleration to relativistic speeds is energy-limited, and therefore you would also need a very powerful energy source to build an RKI (also, as a consequence the RKI would probably glow brightly - at least in infrared - on approach, which makes it easier to identify - unless you accelerate it from very far away so it has time to cool down again). But in a future where both Mach drives and compact nuclear fusion are commonplace, at least state actors should have no problem setting up a fleet of RKIs in the Kuiper belt or beyond.

Quote from: tchernik
If position and visibility become a risk, the solution is to hide, make backups and expand.

Exactly.

Quote
Of course, it is doubtful Earth could never be fully evacuated in any meaningful time frame, therefore a parallel state machinery of surveillance and tight regulation of the METs would emerge (the same as with nuclear power), where every single private MET thruster is accounted for, tracked and could be remotely disabled. And probably within some radius of Earth, no object would be allowed to move above certain speeds or follow an accelerating trajectory of more than certain fractions of G.

That radius would have to be very big (probably encompass the solar system or so) to make sure any rogue Mach drives could be intercepted in time. But then, how would you track those who do not want to be tracked? As long as you have different states with different interests, surveillance / regulation will always serve the needs of these interests.

So I agree - the diaspora would be likely to happen. On these ships going into hiding/riding, you can even have a comfy 1 Ge - just accelerate constantly with your Mach drive (but not in a fully deterministic fashion). Go see the universe. All you need is something to feed your fusion reactor with, but that, you can get from everywhere. And hey, at 1 Ge acceleration, the next star system is only a few years of travel away. That's certainly doable, right? And while we're at it: the galactic center is only 30 years away, 60 if you want to stop...

your missing my point. The reason we have to restrict access to fusion/fission bombs is because WE HAVE BUT ONE  PLANET. and that weaponry can destroy the one planet we have. Heavy Lift MET's basically remove the biggest barrier to humanity only having a single planet it can live on. Heavy Lift MET's  will basically lead us to moving off planet. There are other technologies we need. but it is my position that those technologies do not see alot of investment because the market doesnt believe there is a need. heavy lift MET's would automatically generate a market need while providing the buyers with a variety of business opportunities to fund development/procurement of that need. That means at most their would be a short term threat. but long term humanity would be sufficiently spread out across the inner and possibly outer solar system than relativistic impactors just become a nice way to piss off people. instead of being the end of humanity scenario it is today.

One other thing I forgot to mention. heavy lift met's also provide you with a protection system. if you have complete coverage of the sky to detect them. then you just need a drone pulling  many many G's of constant acceleration to pull up along side and alter its course. Or take the SPS system and use it to power a GW Laser. again relativistic impactors are not a great concern here

Well, there will certainly be a dangerous transition period where RKIs are an existential risk for all of humanity (when we can build them already, but haven't moved into space habitats in large numbers yet). If we survive that period, then, yes, humanity as a whole will survive, but still, the need to protect large portions of the population from multi-Megaton-range sneak attacks from interplanetary space will remain. After one RKI wipes out a city, as a politician would you really tell your electorate that you are not doing anything about it because other people moved to other places and thus, humanity will survive?

The surface of any other planet, asteroid, or moon isn't safer than Earth by the way - these are all places where you can deterministically predict where the population centers will be, within a few meters, for thousands of years into the future. The only safe place, in the long run, is on ships equiped with their own Mach drive (certainly at war time, but then, for some organizations on this planet, its always war time...).

To alter the course of an RKI (even more so, pull up along side! much more efficient to just collide with it), you need time. To get time, you have to find them very far out. This is not easy to begin with - we can scan the whole sky today (we do), but we are not only limited by magnitude (the limit of how much light the object we are looking for reflects, or in this case, emits), but also by processing power to find the actual object amongst the billions of background stars and asteroids and cosmic-ray hits. Especially if an RKI is on a direct approach course, it will have very limited tangential velocity, so it will be difficult to spot as it looks like a very hot but tiny background star... Then, RKIs are moving at relativistic speeds, so most of that safety distance will actually be needed just to get their photons into the telescope (e.g., at 90% of c, finding them out at 10 Earth-Moon distances only gives you one second to react from the moment their light reaches the telescope - then they impact). Today, it would be completely hopeless to find objects of a few kg even in cislunar space... (and, btw, there is also a physical/optical limit to how good a telescope you can build to find these things).

Lasers are also of no good use here, because even if you vaporize the RKI with a laser, the ion velocities in the resulting plasma will still be very small compared to the relativistic forward velocity, and thus this will not make much of a difference (as builder of the RKI, you could even help this by using very heavy building materials which are difficult to accelerate, like tungsten). It doesn't really matter if the Earth is hit by a lob or tungsten or a cloud of tungsten atoms of the same mass, if it is at relativistic velocities. Also, it is by no means given that the approaching RKI would agree to be a passive target on a deterministic course. In the last section of its flight, it might accelerate and slightly change course at random, which - given the dimensions involved - would probably make it impossible to hit with a laser.

To protect surface populations against them, you would probably need a system-wide optical/infrared surveillance system (so you could triangulate and cut down on processing power), and then some kind of super-fast interceptor system which has a realistic chance of delivering a punch strong enough so the RKI misses its target.

Offline M.E.T.

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Re: Woodward's effect
« Reply #878 on: 05/02/2017 03:41 PM »
I'm not so sure about easily stopping RKV threats.

How far out could you detect a 1m diameter ball of iron traveling at 95% the speed of light? How about a 10cm diameter ball of iron. And at that speed, your response time would likely be in minutes only, maybe hours at most.

And furthermore, it seems that even Mach Thrusters would take months to get such a device up to 95% the speed of light. To achieve the same speed from rest in a few hours seems unlikely. Yet that would be required to have any hope of intercepting the incoming projectile.

« Last Edit: 05/02/2017 03:41 PM by M.E.T. »

Offline RonM

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Re: Woodward's effect
« Reply #879 on: 05/02/2017 04:08 PM »
I'm not so sure about easily stopping RKV threats.

How far out could you detect a 1m diameter ball of iron traveling at 95% the speed of light? How about a 10cm diameter ball of iron. And at that speed, your response time would likely be in minutes only, maybe hours at most.

And furthermore, it seems that even Mach Thrusters would take months to get such a device up to 95% the speed of light. To achieve the same speed from rest in a few hours seems unlikely. Yet that would be required to have any hope of intercepting the incoming projectile.

Yes, stopping a RKV would be extremely difficult if not impossible.

Let's assume detecting the RKV is not a problem (it would be, but let's say it's not for sake of the following example).

Say we detect a RKV traveling .95c at about 50 AU (outer edge of the Kuiper Belt, say 400 light-minutes away). The RKV is moving almost as fast as the signal preceding it, so by the time we see it at 400 light-minutes away, it's traveled 380 light-minutes. Now it's only 21 minutes from impact.

Not a lot of time left, but our automated defense lasers fire and vapourize it in the nick of time.

Lasers are also of no good use here, because even if you vaporize the RKI with a laser, the ion velocities in the resulting plasma will still be very small compared to the relativistic forward velocity, and thus this will not make much of a difference (as builder of the RKI, you could even help this by using very heavy building materials which are difficult to accelerate, like tungsten). It doesn't really matter if the Earth is hit by a lob or tungsten or a cloud of tungsten atoms of the same mass, if it is at relativistic velocities. Also, it is by no means given that the approaching RKI would agree to be a passive target on a deterministic course. In the last section of its flight, it might accelerate and slightly change course at random, which - given the dimensions involved - would probably make it impossible to hit with a laser.

Oops.

So, even if we detect an incoming RKV at the edge of the Solar System, we can't stop it from doing massive damage to Earth.

This all assumes a threat launched from beyond the Solar System arriving at near lightspeed. Terrorists using vehicles within the Solar System wouldn't have enough room to accelerate to these incredible speeds.