Szydagis' point 3: Interstellar travel is too hard

[Mauro]

Seriously, all one is saying is that QM was a discontinuous (not incremental) scientific paradigm shift. It's hardly an earth-shaking or controversial statement

But if this is just what you intended, in the context of this thread:

So what?

 

[John J.]

when we posit that progress in Science is plateauing

I liked your post, and to paraphrase the American philosopher Donald Rumsfeld there are probably unknown unknowns.
We might discover something (perhaps many things) that makes interstellar travel easier than it would otherwise appear to be.

I don't think anyone here is claiming that science or technology will plateau, though- just that advances might not be limitless.

But, increased knowledge might find a factor or factors that make interstellar flight even more difficult than many might think it to be at present. The universe is under no obligation to make things easy for us.

One finding which might have implications for long duration crewed spaceflight in the near future might be
spaceflight-associated neuro-ocular syndrome (SANS).

Astronauts have recently been discovered to have impaired vision, with a presentation that resembles syndromes of elevated intracranial pressure on Earth.

Content from External Source

J.S. Lawley, L.G. Petersen et al. (2017), "Effect of gravity and microgravity on intracranial pressure", The Journal of Physiology 595 (6)
https://physoc.onlinelibrary.wiley.com/doi/pdfdirect/10.1113/JP273557

Most of the astronauts onboard the International Space Station (ISS) develop visual impairment and ocular structural changes that are not fully reversible upon return to earth.

Content from External Source

N. Alperin, A.M. Bagci (2018), "Spaceflight-Induced Visual Impairment and Globe Deformations in Astronauts Are Linked to Orbital Cerebrospinal Fluid Volume Increase", Acta neurochirurgica supp. 216 (link here)

Spaceflight associated neuro-ocular syndrome (SANS) is common amongst astronauts on long duration space missions and is associated with signs consistent with elevated cerebrospinal fluid (CSF) pressure. Additionally, CSF pressure has been found to be elevated in a significant proportion of astronauts in whom lumbar puncture was performed after successful mission completion.

Content from External Source

W.H. Morgan, J. Khoo et al. (2023), "Correlation between retinal vein pulse amplitude, estimated intracranial pressure, and postural change", npj Microgravity 9
https://www.nature.com/articles/s41526-023-00269-0

In the past, many terms were used to describe the symptoms of malaise, nausea, vomiting, and vertigo, though longer duration spaceflights have increased the prevalence of overlapping symptoms of headache and visual disturbance. Spaceflight-induced visual pathology is thought to be a manifestation of increased intracranial pressure (ICP) because of its similar presentation to cases of known intracranial hypertension on Earth as well as the documentation of increased ICP by lumbar puncture in symptomatic astronauts upon return to gravity.

Content from External Source

A.P. Michael, K. Marshall-Bowman (2015), "Spaceflight-Induced Intracranial Hypertension", Aerospace medicine and human performance 86 (6),
https://pubmed.ncbi.nlm.nih.gov/26099128/

There is some evidence that effects on vision may persist post-mission, at least in some astronauts.
Spaceflight-associated choroidal folds (wrinkling of the tissues behind the retina) does appear to persist, albeit without detected effects on vision so far.
Anecdotally, there is concern at NASA that intracranial pressure may also remain elevated post-mission, and/or might become more prevalent on missions of longer duration:
At least one of the authors of "Mean intracranial pressure monitoring by a non-invasive audiological technique: a pilot study"
(A. Reid, R.J. Marchbanks et al. 1989, Journal of Neurology, Neurosurgery and Psychiatry 52 (5), https://jnnp.bmj.com/content/52/5/610) continued researching non-invasive ICP monitoring and has worked with NASA in more recent years (2010s+) in an attempt to develop reliable non-invasive ICP monitoring for use in-flight because of this concern.

“SANS represents a critical risk for deep space exploration, where astronauts will experience spaceflight for longer periods of time and cannot easily return to Earth to address a medical emergency,” says HRP chief scientist Jennifer Fogarty.
“The idea of embarking on a long-duration flight to Mars without having made this discovery is mind-boggling,” Barratt adds. “We would have had people taking voyages of up to three years and coming back with all these problems that would have taken us forever to figure out.”

Content from External Source

NASA website article International Space Station Research Keeps an Eye on Vision Changes in Space, Melissa Gaskill, 04 August 2020 https://www.nasa.gov/humans-in-spac...arch-keeps-an-eye-on-vision-changes-in-space/

Should be said, while effects of SANS on the eye are indisputable, there isn't a clear consensus that raised ICP is the cause.

In "Long-duration spaceflight alters estimated intracranial pressure and cerebral blood velocity", 2021,
The Journal of Physiology 599 (4), 2021 https://physoc.onlinelibrary.wiley.com/doi/10.1113/JP280318,
Ken-Ichi Iwasaki, Yojiro Ogawa et al. found post-flight ICP lower in 9 out of 11 subjects (only 2 S's demonstrated optic disc oedema; both had temporarily raised ICPs.) This appears to contradict related studies.
The authors acknowledge their technique for estimating ICP was not definitive. Michael and Marshall-Bowman (ibid.) and Morgan, Khoo et al. (ibid.) refer to documented raised cerebrospinal fluid pressures found on lumbar puncture of returned astronauts, a better indicator of ICP.

Alperin and Bagci (ibid.) argue that increased orbital (anatomic, not astronomical) CSF pressure might cause the eye deformations seen in astronauts without a general increase in ICP.
Y. Martin Paez, L.I Mudie and P.S. Subramanian (2020) point out

Two main hypotheses are proposed for the pathophysiology of SANS. The first being elevated intracranial pressure and the second compartmentalization of CSF to the globe. These hypotheses are not mutually exclusive...

Content from External Source

"Spaceflight Associated Neuro-Ocular Syndrome (SANS): A Systematic Review and Future Directions", Eye and Brain (2020)12
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7585261/

Martin Paez, Mudie and Subramanian later refer to the more recent paper
"Visual changes after space flight: is it really caused by increased intracranial tension? A systematic review",
R. Elwy, M.A. Soliman, A.A. Hasanain et al. (2020), Journal of Neurosurgical Sciences 64 (5),
https://pubmed.ncbi.nlm.nih.gov/32347675/, whose authors are more certain:

Conclusions: Exposure to microgravity increases ICP possibly precipitating ocular changes. Whether other factors come into play is the subject of investigation. Further randomized studies and methods of direct ICP measurement during spaceflight are needed.

Content from External Source

I read somewhere- and can't find again- that the ISS has a small number of adjustable pairs of glasses for astronauts whose vision deteriorates. If long duration missions can cause raised ICP, that might be harder to mitigate, particularly if ICP continues to rise over time.
One factor which might help a little is reducing the carbon dioxide content of the atmosphere of crewed spacecraft, high blood carbon dioxide can increase ICP.
On the ISS, atmospheric CO might be 5000 ppm, higher at some times. NASA believes this cause some lethargy and headaches amongst crew (not surprised!)
"In-Flight Carbon Dioxide Exposures and Related Symptoms: Association, Susceptibility, and Operational Implications", a NASA technical publication (NASA/TP–2010– 216126), J. Law, S. Watkins, D. Alexander (2010), found via Internet Archive/ Wayback Machine,
PDF attached.

 

[Scaramanga]

On a more serious note, one argument above seems to be that any arriving interstellar visitors would have to be decelerating energetically and in the modern era we'd have at least passively detected a radiation source approaching and arriving in the solar system. For which I guess the believer response would be that the visitors arrived before modern radio astronomy -- the CMB was identified in 1965 -- and/or used a mechanism that decelerates without any emissions.

Well, yes, again we have the basic conservation laws and don't even need to hypothesise weird and wonderful stuff. Any ship decelerating is going to have to use energy to do so. A starship is going to have to use a huge amount of energy to decelerate from light speed, which would make it highly visible. And that's just travel below light speed. At above light speed the warp energy builds up in front of the craft and all gets released on deceleration.....possibly frying the planet they intended to travel to, like some comedy scene out of Hitchhiker's Guide.

 

[Scaramanga]

Lets see what the next 50, 100, 200 years will bring

I guarantee that even the next 200 million years of advance wont overcome the temporal paradoxes inherent in faster than light travel. No amount of scientific advance will do so. Some things will simply always be impossible.

 

[Kacmarek]

I guarantee that even the next 200 million years of advance wont overcome the temporal paradoxes inherent in faster than light travel. No amount of scientific advance will do so. Some things will simply always be impossible.

Entirely possible thay superluminal speed travel is impossible in principle even in the far future .... though, in principle, you, me or Alan Guth cannot guarantee it

But, as inflation theory has demonstrated, nature can have surprises (how the horizon problem was solved)

 

[Kacmarek]

But if this is just what you intended, in the context of this thread:

So ... one cannot dismiss other discontinuous discoveries and innovations in the (near or far) future in principle
Which some of us seem to be arguing in this thread or at least arguing that interstellar travel presents such serious challenges that not only

- we cannot conceive as of now that it would be ever be solved (quite reasonable logical position)
- it would never be solved since various laws of physics and engineering challenges make it virtually impossible (which seems a stretch)

 

[Kacmarek]

Well, yes, again we have the basic conservation laws and don't even need to hypothesise weird and wonderful stuff. Any ship decelerating is going to have to use energy to do so. A starship is going to have to use a huge amount of energy to decelerate from light speed, which would make it highly visible. And that's just travel below light speed. At above light speed the warp energy builds up in front of the craft and all gets released on deceleration.....possibly frying the planet they intended to travel to, like some comedy scene out of Hitchhiker's Guide.

I liked your post, and to paraphrase the American philosopher Donald Rumsfeld there are probably unknown unknowns.
We might discover something (perhaps many things) that makes interstellar travel easier than it would otherwise appear to be.

I don't think anyone here is claiming that science or technology will plateau, though- just that advances might not be limitless.

But, increased knowledge might find a factor or factors that make interstellar flight even more difficult than many might think it to be at present. The universe is under no obligation to make things easy for us.

One finding which might have implications for long duration crewed spaceflight in the near future might be
spaceflight-associated neuro-ocular syndrome (SANS).

Astronauts have recently been discovered to have impaired vision, with a presentation that resembles syndromes of elevated intracranial pressure on Earth.

Content from External Source

J.S. Lawley, L.G. Petersen et al. (2017), "Effect of gravity and microgravity on intracranial pressure", The Journal of Physiology 595 (6)
https://physoc.onlinelibrary.wiley.com/doi/pdfdirect/10.1113/JP273557

Most of the astronauts onboard the International Space Station (ISS) develop visual impairment and ocular structural changes that are not fully reversible upon return to earth.

Content from External Source

N. Alperin, A.M. Bagci (2018), "Spaceflight-Induced Visual Impairment and Globe Deformations in Astronauts Are Linked to Orbital Cerebrospinal Fluid Volume Increase", Acta neurochirurgica supp. 216 (link here)

Spaceflight associated neuro-ocular syndrome (SANS) is common amongst astronauts on long duration space missions and is associated with signs consistent with elevated cerebrospinal fluid (CSF) pressure. Additionally, CSF pressure has been found to be elevated in a significant proportion of astronauts in whom lumbar puncture was performed after successful mission completion.

Content from External Source

W.H. Morgan, J. Khoo et al. (2023), "Correlation between retinal vein pulse amplitude, estimated intracranial pressure, and postural change", npj Microgravity 9
https://www.nature.com/articles/s41526-023-00269-0

In the past, many terms were used to describe the symptoms of malaise, nausea, vomiting, and vertigo, though longer duration spaceflights have increased the prevalence of overlapping symptoms of headache and visual disturbance. Spaceflight-induced visual pathology is thought to be a manifestation of increased intracranial pressure (ICP) because of its similar presentation to cases of known intracranial hypertension on Earth as well as the documentation of increased ICP by lumbar puncture in symptomatic astronauts upon return to gravity.

Content from External Source

A.P. Michael, K. Marshall-Bowman (2015), "Spaceflight-Induced Intracranial Hypertension", Aerospace medicine and human performance 86 (6),
https://pubmed.ncbi.nlm.nih.gov/26099128/

There is some evidence that effects on vision may persist post-mission, at least in some astronauts.
Spaceflight-associated choroidal folds (wrinkling of the tissues behind the retina) does appear to persist, albeit without detected effects on vision so far.
Anecdotally, there is concern at NASA that intracranial pressure may also remain elevated post-mission, and/or might become more prevalent on missions of longer duration:
At least one of the authors of "Mean intracranial pressure monitoring by a non-invasive audiological technique: a pilot study"
(A. Reid, R.J. Marchbanks et al. 1989, Journal of Neurology, Neurosurgery and Psychiatry 52 (5), https://jnnp.bmj.com/content/52/5/610) continued researching non-invasive ICP monitoring and has worked with NASA in more recent years (2010s+) in an attempt to develop reliable non-invasive ICP monitoring for use in-flight because of this concern.

“SANS represents a critical risk for deep space exploration, where astronauts will experience spaceflight for longer periods of time and cannot easily return to Earth to address a medical emergency,” says HRP chief scientist Jennifer Fogarty.
“The idea of embarking on a long-duration flight to Mars without having made this discovery is mind-boggling,” Barratt adds. “We would have had people taking voyages of up to three years and coming back with all these problems that would have taken us forever to figure out.”

Content from External Source

NASA website article International Space Station Research Keeps an Eye on Vision Changes in Space, Melissa Gaskill, 04 August 2020 https://www.nasa.gov/humans-in-spac...arch-keeps-an-eye-on-vision-changes-in-space/

Should be said, while effects of SANS on the eye are indisputable, there isn't a clear consensus that raised ICP is the cause.

In "Long-duration spaceflight alters estimated intracranial pressure and cerebral blood velocity", 2021,
The Journal of Physiology 599 (4), 2021 https://physoc.onlinelibrary.wiley.com/doi/10.1113/JP280318,
Ken-Ichi Iwasaki, Yojiro Ogawa et al. found post-flight ICP lower in 9 out of 11 subjects (only 2 S's demonstrated optic disc oedema; both had temporarily raised ICPs.) This appears to contradict related studies.
The authors acknowledge their technique for estimating ICP was not definitive. Michael and Marshall-Bowman (ibid.) and Morgan, Khoo et al. (ibid.) refer to documented raised cerebrospinal fluid pressures found on lumbar puncture of returned astronauts, a better indicator of ICP.

Alperin and Bagci (ibid.) argue that increased orbital (anatomic, not astronomical) CSF pressure might cause the eye deformations seen in astronauts without a general increase in ICP.
Y. Martin Paez, L.I Mudie and P.S. Subramanian (2020) point out

Two main hypotheses are proposed for the pathophysiology of SANS. The first being elevated intracranial pressure and the second compartmentalization of CSF to the globe. These hypotheses are not mutually exclusive...

Content from External Source

"Spaceflight Associated Neuro-Ocular Syndrome (SANS): A Systematic Review and Future Directions", Eye and Brain (2020)12
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7585261/

Martin Paez, Mudie and Subramanian later refer to the more recent paper
"Visual changes after space flight: is it really caused by increased intracranial tension? A systematic review",
R. Elwy, M.A. Soliman, A.A. Hasanain et al. (2020), Journal of Neurosurgical Sciences 64 (5),
https://pubmed.ncbi.nlm.nih.gov/32347675/, whose authors are more certain:

Conclusions: Exposure to microgravity increases ICP possibly precipitating ocular changes. Whether other factors come into play is the subject of investigation. Further randomized studies and methods of direct ICP measurement during spaceflight are needed.

Content from External Source

I read somewhere- and can't find again- that the ISS has a small number of adjustable pairs of glasses for astronauts whose vision deteriorates. If long duration missions can cause raised ICP, that might be harder to mitigate, particularly if ICP continues to rise over time.
One factor which might help a little is reducing the carbon dioxide content of the atmosphere of crewed spacecraft, high blood carbon dioxide can increase ICP.
On the ISS, atmospheric CO might be 5000 ppm, higher at some times. NASA believes this cause some lethargy and headaches amongst crew (not surprised!)
"In-Flight Carbon Dioxide Exposures and Related Symptoms: Association, Susceptibility, and Operational Implications", a NASA technical publication (NASA/TP–2010– 216126), J. Law, S. Watkins, D. Alexander (2010), found via Internet Archive/ Wayback Machine,
PDF attached.

Extremely detailed citations, seems health effects on human astronauts even in long-term near earth orbit is quite debilitating, interstellar travel would have much worse health implications ....

 

[Mauro]

So ... one cannot dismiss other discontinuous discoveries and innovations in the (near or far) future in principle
Which some of us seem to be arguing in this thread or at least arguing that interstellar travel presents such serious challenges that not only

- we cannot conceive as of now that it would be ever be solved (quite reasonable logical position)
- it would never be solved since various laws of physics and engineering challenges make it virtually impossible (which seems a stretch)

Eh, @Kacmarek, you should really try to hone a bit your logic. Let me help you a bit, if I can.

In your post #156 you argue Quantum Mechanics...

QM was/is not incremental at all, marked a significant departure from the deterministic description of the world till that point and moved physics in a completely different direction. And its experimental predictions have been repeatedly verified experimentally over many many years.
Similar step changes in other branches of physics followed - QED, QCD, modern cosmology, elementary particle physics, chaos and complexity to name a few.

... which are ideas no one here disputes, at all (for sure I don't!).

But then, why did you say that, in the context of this thread, where your position is (if I'm not mistaken) that new scientific discoveries happen to remove previous limits to what we can do, while my position is that it never happened, rather the contrary? It shouldn't have been necessary because I had already talked about QM in post #67...

Quantum theory (one of the examples you proposed), with its fundamental randomness, put a nail in the coffin to the idea one could acquire perfect knowledge (Gödel, and then the discovery of chaos put in more nails).

...nonetheless in post #157 I showed you again that with Quantum Mechanics you choose another bad example for your thesis.


Now I guess you realized you had better not have talked about QM at all, because then you answer in post #159:

Seriously, all one is saying is that QM was a discontinuous (not incremental) scientific paradigm shift. It's hardly an earth-shaking or controversial statement

Ah well, okay, from you answer I get I was wrong to think you posted #156 in support of your thesis, you were instead just adding an assertion for color or for effect, so I feel free to ask (post #161):

But if this is just what you intended, in the context of this thread: so what?

Ah, gosh, but no, I was mistaken again, because immediately later (post #166) you are yet at it:

So ... one cannot dismiss other discontinuous discoveries and innovations in the (near or far) future in principle
Which some of us seem to be arguing in this thread or at least arguing that interstellar travel presents such serious challenges that not only.... etc. etc.

Can't you see how you're constantly banging you head against the same wall, round and round?


I'm not enjoiying any more answering you, @Kacmarek. It's straining to have to repeat again and again the same things in an endless circle when you propose again and again the same rebutted arguments. So I'm sorry, but I'm going to put you on ignore for a little while: nothing personal of course but I just got tired and I need some rest. I hope in the meantime you'll learn a little about how logical reasoning works, so our future forums interaction might become more fruitful and less tiresome (for me, at least). I suggest you to start from Wikipedia: fallacy, and pay special attention to cherry picking, straw man, moving the goalposts and non-sequitur. You look seriously interested in learning (that's the reason I engaged with you in the first place), and learning how to reason is the most important skill of all. I bet you'll thank me in the future, probably years from now, but it took years to me too (decades, actually, and I'm not done yet): I sincerly wish you to do better. Cheers!

 

[FatPhil]

Seriously, all one is saying is that QM was a discontinuous (not incremental) scientific paradigm shift. It's hardly an earth-shaking or controversial statement

As it seems your comment was directed at one of my earlier comments, let me be the first to say that your view is certainly supportable. In the 2400+-ish years that are relevant (I'm starting at Aristotle and Epicurus explicitly pondering about the nature of cause and effect, and the implications of a presence or an absence of causality), comparing the viewpoint of the mid-1800s to the mid-1900s certainly *looks like* a paradigm shift.

However, if you zoom into the 1850-1960 area, it certainly looks more continuous. The photoelectric effect was certainly known to be experimentally true, but inexplicable, what would later be called quantisation of energy was noted, but remained a mystery. Planck solved the ultraviolet catastrophe by introducing "bundles" of energy which were quickly renamed to "quanta". The great divine-dice denier himself ran with that, applied it to the photoelectric effect and won a nobel prize. However, this contradicted Maxwell's laws - a crack had appeared in classical theory. A "leap" had already been performed. However, the "aha!" moment that introduced apparent non-determinism was still a *long* way off, we're only two steps of the way to a fully-formed theory, but those to steps are definitely the introduction of the quantum into widely accepted science.

So I'd argue that the science (the process of discovery) of QM was incremental. It's just that implications do seem to require a somewhat binary "go quantum and believe the wierdnesses or reject it" choice. However, because of our very shallow understandings of the "why" of quantum mechanics, even that's no longer a compulsory yes/no choice. Interpretations exist that put determinism back in, such as pilot wave theory, many worlds (from the perspective of one world, but that's the perspective we have), and super-determinism. Feynman would just brush it off as not even bothering to make any choices, just do the maths, get the result, stop worrying about what the implcations are (or "shut up and calculate").

 

[FatPhil]

So ... one cannot dismiss other discontinuous discoveries and innovations in the (near or far) future in principle
Which some of us seem to be arguing in this thread or at least arguing that interstellar travel presents such serious challenges that not only

- we cannot conceive as of now that it would be ever be solved (quite reasonable logical position)
- it would never be solved since various laws of physics and engineering challenges make it virtually impossible (which seems a stretch)

I refrain from dismissing the existence of future paradigm-shifting advancements in science in principle, certainly, but I request that you refrain from assuming them. All such assumptions are sci-fi at this point. The description of the implications of an undiscovered scientific theory carries no more weight to me than the description of the properties of a deity.

I'm glad you used the word "stretch" though; I don't mind my perspective appearing to you as "a stretch" - you've left it within the realms of possibility rather than excluding it absolutely.

 

[Kacmarek]

As it seems your comment was directed at one of my earlier comments, let me be the first to say that your view is certainly supportable. In the 2400+-ish years that are relevant (I'm starting at Aristotle and Epicurus explicitly pondering about the nature of cause and effect, and the implications of a presence or an absence of causality), comparing the viewpoint of the mid-1800s to the mid-1900s certainly *looks like* a paradigm shift.

However, if you zoom into the 1850-1960 area, it certainly looks more continuous. The photoelectric effect was certainly known to be experimentally true, but inexplicable, what would later be called quantisation of energy was noted, but remained a mystery. Planck solved the ultraviolet catastrophe by introducing "bundles" of energy which were quickly renamed to "quanta". The great divine-dice denier himself ran with that, applied it to the photoelectric effect and won a nobel prize. However, this contradicted Maxwell's laws - a crack had appeared in classical theory. A "leap" had already been performed. However, the "aha!" moment that introduced apparent non-determinism was still a *long* way off, we're only two steps of the way to a fully-formed theory, but those to steps are definitely the introduction of the quantum into widely accepted science.

So I'd argue that the science (the process of discovery) of QM was incremental. It's just that implications do seem to require a somewhat binary "go quantum and believe the wierdnesses or reject it" choice. However, because of our very shallow understandings of the "why" of quantum mechanics, even that's no longer a compulsory yes/no choice. Interpretations exist that put determinism back in, such as pilot wave theory, many worlds (from the perspective of one world, but that's the perspective we have), and super-determinism. Feynman would just brush it off as not even bothering to make any choices, just do the maths, get the result, stop worrying about what the implcations are (or "shut up and calculate").

Agreed that we do not, at this stage, fully grasp or comprehend what QM is all about, and what is the picture of reality it truly represents.

Also agreed that Planck and Enstein tiptoed into it with quantization of energy.
(still not a grand departure from physics as we know it for say the last 1000 years)

But wave-particle duality, the Heisenberg uncertainty principle and the Schrodinger wave equation (incl the famous Schrodinger's Cat gedankenexperiment) makes it amply clear the QM describes a world (microscopic, for sure, with imperceptible effects in our macroscopic world) which are far from the world of Newton and Maxwell.

Whether the Copenhagen or many-worlds interpretation is correct, both have significant mind-altering implications for reality.

It is a true paradigm shift in my opinion, from a deterministic worldview to a probablistic one (except the earlier statistical formulation of the 2nd law of thermodynamics)

 

[FatPhil]

But wave-particle duality, the Heisenberg uncertainty principle and the Schrodinger wave equation (incl the famous Schrodinger's Cat gedankenexperiment) makes it amply clear the QM describes a world (microscopic, for sure, with imperceptible effects in our macroscopic world) which are far from the world of Newton and Maxwell.

You could still hypothetically have all of those three things without quantum mechanics.

The easiest of the three to show that with is the middle one - a cognate to Heisenberg's uncertainty principle applies to all waves in all media, because, like Noether's Theorem, it's a mathematical law, not a physical one. (And because both are applied in nature to the same ideas of time, space, and "action", you end up with the same pairings - time with energy, and position with momentum.) You can't tell the wavelength of a tsunami from brief footage of a boat rising. There's a chance that's a terrible analogy, but I can't prove to myself it's useless, so is left in so that others can improve on it. Shannon-Nyquist keeps polluting my thought patterns presently, but that's a different theorem (but again related, everything can be mapped onto fourier transforms).

As an aside, back to my earlier argument pro small incremental steps from above, the schroedinger wave equation isn't that much of an evolution from the normal heat equation with potential; the only twist, quite literally, is that the "i" multiplier causes wave-like behavior to drop out in the solutions. Yes, this implies that it technically doesn't have the form of a *wave equation*; someone, de Broglie?, chose the wrong nomenclature about the time they were trying to model matter waves. Removing the word "wave" from its name is tricky, as it's been there too long and seems to have stuck. But if Planck's comment about scientific truths applies to names of things too, the users of the old name will eventually die out.

 

[Kacmarek]

You could still hypothetically have all of those three things without quantum mechanics.

The easiest of the three to show that with is the middle one - a cognate to Heisenberg's uncertainty principle applies to all waves in all media, because, like Noether's Theorem, it's a mathematical law, not a physical one. (And because both are applied in nature to the same ideas of time, space, and "action", you end up with the same pairings - time with energy, and position with momentum.) You can't tell the wavelength of a tsunami from brief footage of a boat rising. There's a chance that's a terrible analogy, but I can't prove to myself it's useless, so is left in so that others can improve on it. Shannon-Nyquist keeps polluting my thought patterns presently, but that's a different theorem (but again related, everything can be mapped onto fourier transforms).

As an aside, back to my earlier argument pro small incremental steps from above, the schroedinger wave equation isn't that much of an evolution from the normal heat equation with potential; the only twist, quite literally, is that the "i" multiplier causes wave-like behavior to drop out in the solutions. Yes, this implies that it technically doesn't have the form of a *wave equation*; someone, de Broglie?, chose the wrong nomenclature about the time they were trying to model matter waves. Removing the word "wave" from its name is tricky, as it's been there too long and seems to have stuck. But if Planck's comment about scientific truths applies to names of things too, the users of the old name will eventually die out.

Yes the Schrodinger wave equation is your basic PDE (heat/fluid dynamics), but the implications of all three things (uncertainty/wave particle/Schroedinger) put together ..... now thats a bit weird from reality perspective.

Some say that John Bell's "Speakable and Unspeakable in Quantum Mechanics" gives a good introduction to many of the key issues of QM vs reality (havent read it myself though)

"Shut up and calculate" as you or someone said sometime back may of course be v useful from the physicist's perspective by ignoring the philosophical issues raised by QM

 

[FatPhil]

Some say that John Bell's "Speakable and Unspeakable in Quantum Mechanics" gives a good introduction to many of the key issues of QM vs reality (havent read it myself though)

Bell proved Einstein wrong. Bell's a hero, Einstein's a stuck-in-the-mud.

What else did you expect me to say. Even the smartest geniuses can be - perhaps - wrong. I sympathise very strongly with Albert, but I don't know enough to make any judgements. So I'm prepared to just go hands off and say "shut up and calculate" even though I know it doesn't answer any "why" questions. I said "prepared", not "happy".

 

[John J.]

Quantum mechanics is obviously a vital cornerstone of modern physics. It is of extraordinary importance.
But in 99 years, it hasn't provided a new form of transport, or enabled any existing mode of transport to move faster or further.
(Skating over claimed "teleportation" of particles at quantum scales here.)

QM doesn't weaken the obstacles that relativity puts in the way of near-c or >c flight.
Nor does QM offer clues to overcoming the 1st and 2nd law of thermodynamics, at least in any way useable on the macro scale.

Maybe a conceptual breakthrough/ paradigm shift on the scale of QM, or greater, will lead to a physics which mitigates or nullifies the above obstacles, which would be cool, but if so current scientists have no idea where that advance will come from.
Such an advance might never be found. It might not exist to be found.

All reliable evidence so far is that >c transport is impossible, not because we aren't smart enough but because it is an inherent and inviolable quality of this universe. This makes me unhappy, and I hope one day humans get to explore, and live on, other planets. But I don't think there's any reason to assume that this will happen .