Szydagis' point 3: Interstellar travel is too hard

[FatPhil]

Never imagined that everyone would be texting constantly, even when cycling in traffic.

A self-solving problem, eventually. However, I also believe that steering wheels should have spikes in the middle of them.

Aside-aside: I had phone problems a few months back (my phone is from 2009 and in true Thesean fashion, it's cobbled together from parts from discarded ones, this particular problem involved the keyboard, an intrinsic part of the motherboard, it needed very invasive surgary), and it was effectively useless. It took me a month before I got round to fixing it, and it was quite liberating to simply be detached from the internet whenever I was out of the flat. I began to notice even more how much other people's faces were buried in their phones all the time.

 

[Mauro]

I don't remember who said it, but someone once came up with a pretty good rule of thumb with "if if violates the laws of thermodynamics, it's probably wrong". Whoever it was, he's been right every time so far.

I remember that quote too (but not who said it ). Iirc it was something like "If your theory violates conservation of energy or of momentum it might still be true, but if it violates the second law it's surely doomed"

 

[Mauro]

Much of what we know about the universe has been discovered in the 20th and 21st centuries

If a force binding constituents of quarks inside protons is discovered tomorrow and it can be harnessed to deploy much large amounts of energy - it would be new physics which we do not know now

Why should we assume that physics and properties of matter/energy will hit a wall and new solutions wont be found

Newton didnt know about protons or neutrons or GR

Einstein didnt know about the black holes existing in space as physical manifestations of solutions to his equations though it had been predicted theoretically

It seems to me you're now beating a dead horse. Let me schematize again in a different form what (I think, I don't want straw-man at all) your reasoning is, and why it fails.

1) Science has made wonderful and unexpected discoveries. This is perfectly true!
2) Those discoveries allowed us to make wonderful things. Which is true too!

3) Then, we can expect science to give us the means to overcome the limits it has discovered (ie.: making interstellar travel a practical thing).

And the conclusion is the part which fails: you can reach it only if you consider just the green curve of post #68. If you do that, your conclusion surely looks sensible. But if you put in all the evidence we have, instead of just cherry picking then green curve, and consider the red one too,

then your argument does not support at all the conclusion that we will be able to overcome the limits science has discovered, on the contrary, it strongly suggest the limits will become even more stringent.

Avoid using this argument again, it's counterproductive for your own cause.

 

[Kacmarek]

It seems to me you're now beating a dead horse. Let me schematize again in a different form what (I think, I don't want straw-man at all) your reasoning is, and why it fails.

1) Science has made wonderful and unexpected discoveries. This is perfectly true!
2) Those discoveries allowed us to make wonderful things. Which is true too!

3) Then, we can expect science to give us the means to overcome the limits it has discovered (ie.: making interstellar travel a practical thing).

And the conclusion is the part which fails: you can reach it only if you consider just the green curve of post #68. If you do that, your conclusion surely looks sensible. But if you put in all the evidence we have, instead of just cherry picking then green curve, and consider the red one too,

View attachment 68667

then your argument does not support at all the conclusion that we will be able to overcome the limits science has discovered, on the contrary, it strongly suggest the limits will become even more stringent.

Avoid using this argument again, it's counterproductive for your own cause.

Yes I think we need to stop beating dead horses.
Final comments on this subject
- When the theory of conservation of energy was postulated (maybe over centuries), it was not known that mass could be converted to energy; is that a fair statement? Discoveries in the 20th century made it (conservation of mass+energy) arising from E = mc^2

Hence, it is not written in stone that the principle of conservation of (mass+energy+(unknown)) cannot arise in the future, to give just one example

I dont think there has been any demonstration that limits of science have been reached ; but at this stage we would just be making declarative statements without sufficient evidence (on both sides of the argument)

 

[Mendel]

I think you meant has, not will, cos the concept of there not being a wall AT ALL is pretty mind blowing.

That's the Flat Earther attitude to Space.

A limit need not be a wall.

 

[Scaramanga]

The problem of interstellar travel taking 'too long' is largely resolved if robots rather than biological creatures are used. So the only real remaining problem is communication. The inability to communicate faster than light makes nonsense of galaxy spanning civilisations, as civilisation without rapid communications cannot really be said to be a coherent unit.

 

[Mauro]

The problem of interstellar travel taking 'too long' is largely resolved if robots rather than biological creatures are used. So the only real remaining problem is communication. The inability to communicate faster than light makes nonsense of galaxy spanning civilisations, as civilisation without rapid communications cannot really be said to be a coherent unit.

I'm not really sure a machine would outlast a biological being, this because biologicals have a built-in and very efficient self-repair system which machines lack (ie.: trees can live thousands of years, and just on CO2 and light). I'd rather see as more probable to be able to bio-engineer humans (or little green men) with a lifespan of, say 500 years (and able to survive hundreds of years of boredom), than be able to build a machine which lasts as long. One can imagine a self-repairing machine of course (I can't really see any fundamental physical principle forbidding it) but, on the other side, reaching the performance of biological system (which work at the atomic scale) seems quite improbable to me (but who knows). Also, one would also need a civilizations of robots, because it's hard to imagine beings with a lifespan similar to us sending a machine on a trip which will, take, say 10 times their lifespan (~30 generations) before arriving to alfa Centauri to send back some pictures (but yet again, who knows).

A generational ship could solve the problem too, but it would be such a gigantic thing that a 'regular' relativistic probe would seem a small potato compared to it.

I think the best possible chance for interstellar travel is to send a very small probe (from grams to maybe a few kilograms) powered by a lightsail. This has some chances to be actually possible in the future, even if with a small probe the problem of transmitting data back becomes daunting (and this for very good and fundamental physical reasons). In any case, a far cry from a 'UFOs'/'UAPs' and from interstellar travel as commonly intended.

Another possibility is just to survive as a race for some tens of million years, because stars move and in millions of years there will be many which will pass near the Solar System, perhaps even at sub-light year distances. Yeah that would be quite dangerous too (it could de-stabilize the orbits of a lot of bodies, Earth included) but, willing to be optimistic at all costs, it would considerably shorten the interstellar trip.

 

[JMartJr]

civilisation without rapid communications cannot really be said to be a coherent unit.

Agreed to a point. But with the note that, say, the Roman Empire found ways to make a civilization hang together across distances where communication from end to end was a matter of weeks or months (but not the years or centuries or millennia an interstellar empire might face, of course!) Could ways be found to hang together across greater distances in time and space? Maybe. The obvious way, used by the Romans, was a decentralized state with multiple centers of government, which both led to parts of the Empire falling and led to parts of it not being dragged down too, to simplify hugely.

 

[MyMatesBrainwashed]

Hence, it is not written in stone that the principle of conservation of (mass+energy+(unknown)) cannot arise in the future, to give just one example

But that wouldn't break (mass + energy) that preceded it. It's just a new "equals".

It's "not equals" that needs to be found.

 

[MyMatesBrainwashed]

I can't help thinking along the lines of if it was possible to break the rules then the universe would've already done so itself. I assume it can't cos the universe would be a very different place to live if it could.

And if it turns out the rules can be broken then that would suggest that someone or something stops the universe from doing so.

Far more interesting than trying to come up with globe proofs.

 

[PublicStranger]

I remember reading somewhere the theory that if space travelling civilizations existed they would be scattered around the universe as opposed to living on a specific planet and they would operate like some quasi traveller book club who would meet at specific locations every so often. Can't recall where I remember seeing it but it was an interesting conversation.

 

[FatPhil]

I remember reading somewhere the theory that if space travelling civilizations existed they would be scattered around the universe as opposed to living on a specific planet and they would operate like some quasi traveller book club who would meet at specific locations every so often. Can't recall where I remember seeing it but it was an interesting conversation.

Every time they met up, they wouldn't recognise each other, as they'd have evolved into new species!

I hypothesise that rules along the line of "the environment must be preserved so that our evolutionary (lack of) pressure does not cause us to evolve away from our present form" (which would almost certainly necessitate "eugenics" to stop the bell-curve spreading out - even in nett positive directions!) would eventually become nothing but lore, or religion.

 

[Mauro]

Every time they met up, they wouldn't recognise each other, as they'd have evolved into new species!

A very nice SF novel exploring similar themes is The Forever War by Joe Haldeman.

Humanity has got into a war with aliens and the military units move from star to star in highly relativistic spaceships (they also use a sort of wormhole, and they need suspended animation too because trips last years nonetheless). Every time the main character (William Mandella) comes back to Earth, due to time dilation tens or hundreds of years have passed and Earth society becomes more and more unrecognizable to him. At the end of his military carrier Earth's clock has advanced more than a thousand years and humankind has changed so much that he can no more live on Earth, among the "new" humans. He retires on a planetary colony where more veterans like him are lodged and to whom he can relate with.

 

[Scaramanga]

I can't help thinking along the lines of if it was possible to break the rules then the universe would've already done so itself. I assume it can't cos the universe would be a very different place to live if it could.

The major problem with faster than light travel is that it creates temporal paradoxes. It totally disrupts the causal timeline, and you could effectively receive a message before it was sent. You then end up with the grandfather paradox and so on.

Not even warp drives can get round this issue. I mean, they might get round the major problem of light speed travel requiring infinite energy but not even a warp drive can get past the timeline issue.

Much the same applies to the claims by some that UFOs are from the future. That would just as much be subject to temporal paradoxes.

Also, claims that UFOs are 'from another dimension'....yet another hypothesis....might not break temporal rules by they DO break the laws of conservation of energy and quantum information.

 

[JMartJr]

Also, claims that UFOs are 'from another dimension'....yet another hypothesis....might not break temporal rules by they DO break the laws of conservation of energy and quantum information.

I've never been clear on what another dimension would even BE, but if they were to exist, whatever they are, I would suggest that the conservation of energy would just need to be tweaked to include "within the multiverse of dimensions" as opposed to just within "this" universe.

Much the same applies to the claims by some that UFOs are from the future. That would just as much be subject to temporal paradoxes

For that matter, time travel would create conservation issues, with energy/mass ceasing to exist NOW when my time travel disappeared to go back in time, and energy/mass appearing from nowhere back in my target time!

 

[FatPhil]

I've never been clear on what another dimension would even BE, but if they were to exist, whatever they are, I would suggest that the conservation of energy would just need to be tweaked to include "within the multiverse of dimensions" as opposed to just within "this" universe.


For that matter, time travel would create conservation issues, with energy/mass ceasing to exist NOW when my time travel disappeared to go back in time, and energy/mass appearing from nowhere back in my target time!

We don't know if gravity is conservative, so we can't be sure there's a conservation of energy law. Newton was fine, even SR is, but some GR-based theories are non-conservative.

You've also assumed that time travel is a discontinuity in an object's path in spacetime, but there's no reason it should be that way. The Feynmannian analogy of positrons being electrons travelling back in time until they meet themselves moving forward in time and annihilating being a good example of a continuous path that includes time travel.

 

[JMartJr]

You've also assumed that time travel is a discontinuity in an object's path in spacetime

Ha, fair enough, but since from where I sit time travel is fiction, I can assume what I want!

(I recall somebody, Larry Niven I think it was, positing a situation where somebody traveled into the past in their time machine, which wound up in a museum that was built from the metal that was going to be used to build the time machine someday, so it was never built since the materials needed were in the case that it sat in, etc.)

(I'll mention one more, then stop derailing into time travel speculation... but since we're here anyway... Proposition: In any universe where time travel is possible and time travel can change the past, time travel will not be invented. Every time you have a time traveler you get a new universe as they change the past, everything is always in flux, until you happen by chance to hit on a universe in which nobody invents time travel, even though it is possible, and then you're locked in that one... forever.)

 

[Ann K]

until you happen by chance to hit on a universe in which nobody invents time travel, even though it is possible, and then you're locked in that one... forever

...and here we are.

 

[John J.]

- Did nuclear fission violate the law of conservation of energy?

No.
And fission not violating conservation of energy would have been known to a few in 1905.

Wasn't nuclear fission and the strong and weak nuclear forces (binding protons and neutrons in the nucleus) discovered in the 1930s ?

Mass: energy equivalence, E=mc

, discovered in 1905.
An understanding of how to liberate energy by nuclear fission, and later use of that knowledge, didn't give us the ability to obtain energy from nothing. The energy already resides in the pre-fission atoms; a small percentage of fissioned nuclei's mass is converted to energy.

_____________________________________________________________________________________________________________________________________

A very nice SF novel exploring similar themes is The Forever War by Joe Haldeman.

Agreed, a good book.

Haldeman graduated with a BSc in physics and astronomy, and was then drafted. He served as a combat engineer in Vietnam.
The Forever War is often seen as a metaphor for his experiences of service, and returning to a civil society that had "moved on", sometimes in ways he didn't understand (and which in turn didn't understand him). His protagonist Mandella (a near-acronym of Haldeman, and also a drafted physics graduate) subjectively serves for four years, but inevitably finds himself increasingly unfamiliar with Earth culture as it changes over a thousand years of local time.

 

[Gary C]

Interstellar travel is not only hard, it's also likely to be unnecessary.
a. A civilization cannot be very "advanced" if it has not discovered birth control.
b. Lifting resources off a planet in another stellar system is the hardest way to get them.
1. 100% recycling is almost certain to be both technically feasible and use far less energy than any conceivable form of space travel.
2. Elements that don't exist in sufficient quantities in a planet's crust can be obtained from nearby asteroids, comets, or minor planets without leaving one's own stellar system. The smaller the body, the easier it is to locate and collect only what you actually need.

 

[Gary C]

I think the best possible chance for interstellar travel is to send a very small probe (from grams to maybe a few kilograms) powered by a lightsail. This has some chances to be actually possible in the future, even if with a small probe the problem of transmitting data back becomes daunting (and this for very good and fundamental physical reasons). In any case, a far cry from a 'UFOs'/'UAPs' and from interstellar travel as commonly intended.

Some people agree with you ...

Breakthrough Starshot aims to demonstrate proof of concept for ultra-fast light-driven nanocrafts, and lay the foundations for a first launch to Alpha Centauri within the next generation. Along the way, the project could generate important supplementary benefits to astronomy, including solar system exploration and detection of Earth-crossing asteroids.

Source - https://breakthroughinitiatives.org/initiative/3

 

[Kacmarek]

Mass: energy equivalence, E=mcView attachment 68885, discovered in 1905.
An understanding of how to liberate energy by nuclear fission, and later use of that knowledge, didn't give us the ability to obtain energy from nothing. The energy already resides in the pre-fission atoms; a small percentage of fissioned nuclei's mass is converted to energy.

_____________________________________________________________________________________________________________________________________


Agreed, a good book.

Haldeman graduated with a BSc in physics and astronomy, and was then drafted. He served as a combat engineer in Vietnam.
The Forever War is often seen as a metaphor for his experiences of service, and returning to a civil society that had "moved on", sometimes in ways he didn't understand (and which in turn didn't understand him). His protagonist Mandella (a near-acronym of Haldeman, and also a drafted physics graduate) subjectively serves for four years, but inevitably finds himself increasingly unfamiliar with Earth culture as it changes over a thousand years of local time.

E=mc^2 being known and strong nuclear force as well as fission being discovered are related, but different things. It took decades for them to be discovered after Einstein's famous formula was posited.

We know now that quarks (which cannot be isolated), make up protons and neutrons. If we find experimental evidence (after 40 years), that quarks are made up of "salamions" or "weinbergions" (fundamental constituents of matter) and they can be utilised for generation of very high energy, that would be a new discovery.

I am not really sure why we are arguing that all of physics (including high energy and fundamental particle physics) has already been discovered and no further energy sources can be found in the future. That may not be the argument, but sure feels that way (I may be wrong)

 

[LilWabbit]

I am not really sure why we are arguing that all of physics (including high energy and fundamental particle physics) has already been discovered and no further energy sources can be found in the future.

Welcome to MB!

That's not what we're arguing. We're essentially arguing the following:

To modify highly successful general theories of physics -- in a manner that impairs their amazing ability to predict observations -- in order to fit a highly specific alien spacecraft hypothesis or equivalent -- is both unscientific and an intellectual copout. Fiddling with energy conditions and negative mass speculations to fit certain subjectively exciting ideas for propulsion technology inspired by science fiction is just a case in point.

It's a form of intellectual laziness disrespecting the empirical merit of successful theories of physics that haven't ceased to be successful -- even Newtonian mechanics remains highly predictive in lower velocities. It's a form of theoretical violence that's not really interested in the hard work of science but in modifying the whole established framework to fit a particular faith-based narrative. That's what 'ufologist' 'scientists' do. They aren't content by merely claiming the truism that science is bound to discover new things. Nobody disagrees with the truism.

If these 'scientists' are really willing and able to put in the hard work of formulating new general theories that are more successful than the current ones in their theory-predictions (i.e. testability), any scientist worth their salt should welcome such theories wholeheartedly for further exploration.

Such, however, hasn't been the nature and pattern of most of these speculations. Having said that, speculative theoretical excursions such as the many-worlds interpretation of QM, multiverse theoretizations, illusory time theoretizations, even n-dimensional strings et cetera are not on a much firmer footing scientifically/empirically. But some of them are considered 'less fringe' due to their agreement with certain mainstream / popularized philosophical ideas about the nature of existence, rather than their actual scientific merit. Despite being just as 'unicorn' as negative mass warp drives. Until of course proven otherwise.

To put it in another way, there's no shortcut to 'novel' and 'revolutionary' theories of physics. The history of successful physical theories demonstrates their astounding ability to predict observations and measurement outcomes in increasingly greater/finer energy and spacetime scales. As such, this empirical success imposes a formidable standard of rigour for any future scientific revolutions attempting to challenge these theories because any new 'revolutionary' theory must be able to be at least as successful in predicting these very same observations, and not only the anomalies they've set out to explain with contrived ad hoc calculational tweaks.

 

[FatPhil]

Some people agree with you ...

Breakthrough Starshot aims to demonstrate proof of concept for ultra-fast light-driven nanocrafts, and lay the foundations for a first launch to Alpha Centauri within the next generation. Along the way, the project could generate important supplementary benefits to astronomy, including solar system exploration and detection of Earth-crossing asteroids.

Source - https://breakthroughinitiatives.org/initiative/3

The word "could" is doing a lot of work in that sentence. I would expand on that, but I need to rush to a local shop where there's a sale - everything's up to 100% off!

 

[Kacmarek]

Welcome to MB!

That's not what we're arguing. We're essentially arguing the following:

To modify highly successful general theories of physics -- in a manner that impairs their amazing ability to predict observations -- in order to fit a highly specific alien spacecraft hypothesis or equivalent -- is both unscientific and an intellectual copout. Fiddling with energy conditions and negative mass speculations to fit certain subjectively exciting ideas for propulsion technology inspired by science fiction is just a case in point.

It's a form of intellectual laziness disrespecting the empirical merit of successful theories of physics that haven't ceased to be successful -- even Newtonian mechanics remains highly predictive in lower velocities. It's a form of theoretical violence that's not really interested in the hard work of science but in modifying the whole established framework to fit a particular faith-based narrative. That's what 'ufologist' 'scientists' do. They aren't content by merely claiming the truism that science is bound to discover new things. Nobody disagrees with the truism.

If these 'scientists' are really willing and able to put in the hard work of formulating new general theories that are more successful than the current ones in their theory-predictions (i.e. testability), any scientist worth their salt should welcome such theories wholeheartedly for further exploration.

Such, however, hasn't been the nature and pattern of most of these speculations. Having said that, speculative theoretical excursions such as the many-worlds interpretation of QM, multiverse theoretizations, illusory time theoretizations, even n-dimensional strings et cetera are not on a much firmer footing scientifically/empirically. But some of them are considered 'less fringe' due to their agreement with certain mainstream / popularized philosophical ideas about the nature of existence, rather than their actual scientific merit. Despite being just as 'unicorn' as negative mass warp drives. Until of course proven otherwise.

To put it in another way, there's no shortcut to 'novel' and 'revolutionary' theories of physics. The history of successful physical theories demonstrates their astounding ability to predict observations and measurement outcomes in increasingly greater/finer energy and spacetime scales. As such, this empirical success imposes a formidable standard of rigour for any future scientific revolutions attempting to challenge these theories because any new 'revolutionary' theory must be able to be at least as successful in predicting these very same observations, and not only the anomalies they've set out to explain with contrived ad hoc calculational tweaks.

Thanks for the welcome
It does seem that one is beating a (dead or hackneyed) horse, but the issue being discussed is perhaps, worth a debate.

The issue is : high interstellar speeds require very high energies and hence need significant amounts of fuel. This is true as of now.

The principle of conservation of energy holds in the case of fission or fusion, but the total energy that is conserved (along with heat and light) also includes the nuclear binding energy which is derived from the strong nuclear force.
This force has been discovered a mere 100-110 years ago.
All of human science and its greatest scientists before the 20th century, (including Newton and and Faraday and Maxwell and Laplace and Lavoisier) did not know that fission or fusion could produce such extreme levels of energy. They knew that burning a substance would produce heat and light, hence a certain limitation in how much energy couod be extracted from a certain volume.

The principle did not change, but physicists discovered new sources of energy.

We may find other ways of moving objects in space time; Some have been proposed, there seem to be enormous practical difficulties as of today in realising any of those speculative theories.
But we cannot predict how the issue of interstellar travel will be resolved in the next 100, 200 or 500 years. Maybe it will not get solved, maybe it will.

At this stage, we do not know. I feel that is the only reasonable answer.

 

[JMartJr]

At this stage, we do not know. I feel that is the only reasonable answer.

I feel that is a reasonable position. (Caveat: I am not a physicist, nor have I played one on TV. )

However, when evaluating the possibility of interstellar travel being widespread "out there," reliance on "we don't know" seems unhelpful. Hard to assign probabilities to an unknown! At the end of the day, we can either work within the confines what we know or just give up and resort to just guessing.

I think 99% of the folks here would be very happy to learn that some new discovery opens the door to practical interstellar travel. But this being a skeptical sort of place, the Missouri of the Internet*, proof of that will have to come first, THEN probabilities can be reassessed and such.


*

 

[John J.]

I am not really sure why we are arguing that all of physics (including high energy and fundamental particle physics) has already been discovered and no further energy sources can be found in the future. That may not be the argument, but sure feels that way (I may be wrong)

Oh no, I'm not saying that- and I'm very much in favour of physics research, including "blue sky" stuff.
But I think there's a big difference in expanding our knowledge, and hopefully later being able to utilise that knowledge, and hoping that more knowledge will overturn some physical constraints.

I like to imagine that we'll find workarounds or loopholes for, say, relativity, so we can have interstellar flight, but (as far as I understand) there's no persuasive reason to believe that such loopholes/ workarounds will be found.
Not so much because we haven't discovered them yet, or don't have sufficient knowledge to use them, but that they don't exist.
Which sucks.

But who knows.
Just thinking about hyperspace; if it's discovered and accessed by British scientists, you can guarantee it will make distances between two points longer, travel more expensive, make you age faster and physically limit all speeds to 27 m.p.h.
That's what the Highways Agency's detours do here anyway.

 

[LilWabbit]

The principle of conservation of energy holds in the case of fission or fusion, but the total energy that is conserved (along with heat and light) also includes the nuclear binding energy which is derived from the strong nuclear force.
This force has been discovered a mere 100-110 years ago.

But the sun and the stars -- powered by fusion the hypothesis of which also predicts their observation -- have been reliably observed far longer by various detectors including the human eyes. Yours and mine can observe them reliably every day.

The equivalent isn't true to warp drives and such which remain purely speculative even as observations let alone the energy sources that are claimed to power them.

The previous two paragraphs demonstrate the difference between real (read: empirical) science and pure speculation.

 

[FatPhil]

But the sun and the stars -- powered by fusion the hypothesis of which also predicts their observation -- have been reliably observed far longer by various detectors including the human eyes. Yours and mine can observe them reliably every day.

The equivalent isn't true to warp drives and such which remain purely speculative even as observations let alone the energy sources that are claimed to power them.

The previous two paragraphs demonstrate the difference between real (read: empirical) science and pure speculation.

The sun is a wonderful source for examples of scientific speculation based on what was observed. It was known nearly 500 years ago that the sun was capable of applying a pressure or a force on another remote object. This was well over a century before Newton's corpuscular theory of light (which correctly gave light particles momentum, as per Einstein much later, but unfortunately got the order of the mass-equivalents the wrong way round - heavier photons deflect more). Peter Apian, né Bienewicz, noticed that comet tails point away from the sun - the sun must be blowing them somehow. Yay - he's unknowingly discovered the solar wind! Of course, at this point I shouldn't mention that this wonderful insight came from someone who believed in the geocentric model. 400 years later, when people who did understand that concept of the subatomic, the nuclear, and even the quantum, there was even further speculation about what the cause of solar wind might be, and large proportions of those were wrong (e.g. they're not the output from the solar fusion reactions, they don't have the spiky energy spectrum that such a source would be obliged to provide). However, even if they were wrong, they were all created to satisfy something that was actually observed.

 

[Kacmarek]

But the sun and the stars -- powered by fusion the hypothesis of which also predicts their observation -- have been reliably observed far longer by various detectors including the human eyes. Yours and mine can observe them reliably every day.

The equivalent isn't true to warp drives and such which remain purely speculative even as observations let alone the energy sources that are claimed to power them.

The previous two paragraphs demonstrate the difference between real (read: empirical) science and pure speculation.

Agree that the Sun and its properties have been observed for long
We also have to agree that the sources of the sun's energy (gravitational collapse, stellar nucleosynthesis) was not known till the 1920s onwards - obviously, as atomic theory of elements had to be invented before that (and electrons, protons and neutrons had to be discovered before that)

Hence, new physics had to be discovered to explain the sun's energy source
New physics such as quantum mechanics, orbital theory, fusion, nuclear forces etc

All backed by hard experimental evidence - no speculation and no science fiction

These marked a significant departure from what was known earlier and paved the way for modern cosmology including the big bang and understanding of the early universe (which again was verified empirically by experimental observation such as cosmic microwave bavkgroujd radiation - homogenous and isotropic

Hence, it is expected that new physics would also be discovered 100, 200 or 500 years from now

 

[Kacmarek]

One example where Einstein himself has been proved wrong (and superseded by new physics) is in the area of black holes.

Karl Schwarzschild in 1916 demonstrated the existence of a spacetime singularity as a consequence of an exact solution of Einstein's GR. Einstein probably never believed that such an object could exist in the physical universe. Those were black holes, detected in the 1960s, and intensively investigated today.

Just one example of how developments in science (and nature itself) can overcome scepticism of even towering intellects such as Einstein.

Agree that the Sun and its properties have been observed for long
We also have to agree that the sources of the sun's energy (gravitational collapse, stellar nucleosynthesis) was not known till the 1920s onwards - obviously, as atomic theory of elements had to be invented before that (and electrons, protons and neutrons had to be discovered before that)

Hence, new physics had to be discovered to explain the sun's energy source
New physics such as quantum mechanics, orbital theory, fusion, nuclear forces etc

All backed by hard experimental evidence - no speculation and no science fiction

These marked a significant departure from what was known earlier and paved the way for modern cosmology including the big bang and understanding of the early universe (which again was verified empirically by experimental observation such as cosmic microwave bavkgroujd radiation - homogenous and isotropic

Hence, it is expected that new physics would also be discovered 100, 200 or 500 years from

 

[JMartJr]

Hence, it is expected that new physics would also be discovered 100, 200 or 500 years from now

I'm not sure that follows. While it is true that we do not know EVERYTHING, we do know SOME things.

If there is a reasonably small number of fundamental principles to be discovered about the Universe and how physics works, we may be close to having them all and there may be no transformatively new physics out there. If there is a very large number, we may be discovering new stuff that changes everything one of these days. But there does not seem (to me at least) to be reason to expect that -- I don't see any justification for assigning even a very tentative probability to that happening. 'Maybe" seems to be about all that can be said.

That is, of course, different from considering whether new ideas will emerge in physics that fine tune increasingly tiny details. That seems inevitable. But that is not the sort of thing that likely opens up the necessaries for easy(er) interstellar travel.

 

[Mauro]

Just one example of how developments in science (and nature itself) can overcome scepticism of even towering intellects such as Einstein.

Please, this is getting boring. Your argument has been rebutted over and over: have mercy and stop presenting it again and again, unless you have a sound argument to counter the rebuttal (which I summarize here in italics and bold for your convenience, hopefully for the last time):

Every scientific discovery has always added limits to what can possibly be done (*), there's no reason to expect anything different for future discoveries. More discoveries = even more limits, most probably.

(*) while at the same time has expanded what can actually be done

 

[LilWabbit]

One example where Einstein himself has been proved wrong (and superseded by new physics) is in the area of black holes.

Karl Schwarzschild in 1916 demonstrated the existence of a spacetime singularity as a consequence of an exact solution of Einstein's GR. Einstein probably never believed that such an object could exist in the physical universe. Those were black holes, detected in the 1960s, and intensively investigated today.

Just one example of how developments in science (and nature itself) can overcome scepticism of even towering intellects such as Einstein.

Indeed, but the skepticism was rationally challenged through an empirical method of science (observable predictions of the theory of GR) to which Einstein as well as Schwarzchild were equally committed as professional scientists.

Schwarzchild didn't engage in science fiction and propose ad hoc modifications to GR that would have undermined its predictive power whereas ufologists do. They contrive ad hoc tweaks of established theories in order to make space for warp drives (unobserved, mind you) and what not. So-called hard science is always open-minded to new discoveries within its basic methodological constraints (empirical evidence). New fundamental theories are welcomed but they must yield new measurement outcomes (black holes predicted by GR are a case in point) whilst also predicting all the old measurements successfully predicted by older established theories with lesser precision. In short, successful theories must be consistent with all reliable observations. Not just some. Unlike the sun (an observation) and nuclear fusion (one of the hypothesized mechanisms for its observable properties), there's no reliable observation of a negative gravity warp drive to even entertain negative mass as a serious hypothesis worth exploring as an explanation. We have fuzzy grainy blobs whizzing about at best.

You're barking at the wrong tree and at skeptical caricatures of your own making if you really think them 'skeptical' folks at MB deny future scientific revolutions.

And yet, the notion that successful revolutionary theories of physics have refuted successful earlier theories is a simplistic false narrative of the history of physics. Let it be clarified that by a 'successful theory' is hereby meant any hypothesis consistently generating accurate predictions that can be verified by reliable observation. 'Old science is always refuted by newer science' is a simplistic but false common trope used by the ufologist to entertain magic without sounding unscientific.

 

[Kacmarek]

I'm not sure that follows. While it is true that we do not know EVERYTHING, we do know SOME things.

If there is a reasonably small number of fundamental principles to be discovered about the Universe and how physics works, we may be close to having them all and there may be no transformatively new physics out there. If there is a very large number, we may be discovering new stuff that changes everything one of these days. But there does not seem (to me at least) to be reason to expect that -- I don't see any justification for assigning even a very tentative probability to that happening. 'Maybe" seems to be about all that can be said.

That is, of course, different from considering whether new ideas will emerge in physics that fine tune increasingly tiny details. That seems inevitable. But that is not the sort of thing that likely opens up the necessaries for easy(er) interstellar travel.

Very fair and appreciate your nuanced comment. Just a few areas where physics "may be" transformative and not incremental - again, it is inherently difficult to prpject 100 or 200 years ahead far less 500 years ahead :


- structure of matter at levels below what we have probed (what are quarks made of etc)
- Implications of string theory being an accurate description of reality
- What happens inside the event horizon of black holes and at the singularity
- Understanding gamma ray bursts (maybe harness them sonetime in the future?
- Quantum theory of gravity or alternative routes to unifying fundamental forces of physics esp gravity with electroweak and strong nuclear force
- Resolving various issues and paradoxes of quantum theory as a valid description of reality
- Understanding abiogenesis (how did life evolve?), so far no clear answers
- Resolving the Fermi paradox

Answers to some of these may have implications for interstellar travel

Again, it is very difficult to look that far ahead - no scientist has so far being able to do that, not even Einstein or Newton

 

[Kacmarek]

Indeed, but the skepticism was rationally challenged through an empirical method of science (observable predictions of the theory of GR) to which Einstein as well as Schwarzchild were equally committed as professional scientists.

Schwarzchild didn't engage in science fiction and propose ad hoc modifications to GR that would have undermined its predictive power whereas ufologists do. They contrive ad hoc tweaks of established theories in order to make space for warp drives (unobserved, mind you) and what not. So-called hard science is always open-minded to new discoveries within its basic methodological constraints (empirical evidence). New fundamental theories are welcomed but they must yield new measurement outcomes (black holes predicted by GR are a case in point) whilst also predicting all the old measurements successfully predicted by older established theories with lesser precision. In short, successful theories must be consistent with all reliable observations. Not just some. Unlike the sun (an observation) and nuclear fusion (one of the hypothesized mechanisms for its observable properties), there's no reliable observation of a negative gravity warp drive to even entertain negative mass as a serious hypothesis worth exploring as an explanation. We have fuzzy grainy blobs whizzing about at best.

You're barking at the wrong tree and at skeptical caricatures of your own making if you really think them 'skeptical' folks at MB deny future scientific revolutions.

And yet, the notion that successful revolutionary theories of physics have refuted successful earlier theories is a simplistic false narrative of the history of physics. Let it be clarified that by a 'successful theory' is hereby meant any hypothesis consistently generating accurate predictions that can be verified by reliable observation. 'Old science is always refuted by newer science' is a simplistic but false common trope used by the ufologist to entertain magic without sounding unscientific.

We are discussing basically one thing:
Interstellar travel is hard. Is it impossible?

I dont think I have invoked ufology or warp drive even once

 

[Kacmarek]

Please, this is getting boring. Your argument has been rebutted over and over: have mercy and stop presenting it again and again, unless you have a sound argument to counter the rebuttal (which I summarize here in italics and bold for your convenience, hopefully for the last time):

Every scientific discovery has always added limits to what can possibly be done (*), there's no reason to expect anything different for future discoveries. More discoveries = even more limits, most probably.

(*) while at the same time has expanded what can actually be done

<< Every scientific discovery has always added limits to what can possibly be done >>

This is a remarkable statement and I dare say, if I may, that no scientist would make such a statement.

2 counter-examples :

1) Before the discovery of Hubble's law and the discovery of galaxies, the bound of known universe was significantly smaller. Science helped expand that horizon to a current observable universe to 93 billion light years (yes it is expanding horizons and not what can be done)

2) Superconductivity - electrical resistance drops to zero below a certain critical value

There are literally hundreds of such examples

 

[LilWabbit]

We are discussing basically one thing:
Interstellar travel is hard. Is it impossible?

I dont think I have invoked ufology or warp drive even once

You've implied a categorical skeptical position of 'yes' to your question 'Is it impossible?' That's a strawman argument and an incorrect reading of 'skeptical' responses.

We've explained on many threads that specific claims like anti-gravity warp drives are impossible within known physical constraints which, in turn, are supported by hard evidence. Whether you propose warp drives or not is up to you.

 

[LilWabbit]

<< Every scientific discovery has always added limits to what can possibly be done >>

This is a remarkable statement and I dare say, if I may, that no scientist would make such a statement.

2 counter-examples :

1) Before the discovery of Hubble's law and the discovery of galaxies, the bound of known universe was significantly smaller. Science helped expand that horizon to a current observable universe to 93 billion light years (yes it is expanding horizons and not what can be done)

Not really a counter-example to 'a discovery adding a limit to possibilities' which, by the way, is a logical truism. Every new piece of knowledge about reality renders its alternative claims untrue and hence rules them out (i.e. adds limits to possibilities) from the realm of knowables. @Mauro said every 'discovery' adds limits to future possibilities whilst you're talking about the bounds of the known universe expanding overtime which is just another way of saying that our knowledge increases over time. That's another truism. Not a counter-example.

2) Superconductivity - electrical resistance drops to zero below a certain critical value

And how is superconductivity undermining any other discoveries? Mind you, by discovery is meant a new knowledge of what's real. Not just opinions, hypotheses or theories.

 

[Kacmarek]

Not really a counter-example to 'a discovery adding a limit to possibilities' which, by the way, is a logical truism. Every new piece of knowledge about reality renders its alternative claims untrue and hence rules them out (i.e. adds limits to possibilities) from the realm of knowables. @Mauro said every 'discovery' adds limits to future possibilities whilst you're talking about the bounds of the known universe expanding overtime which is just another way of saying that our knowledge increases over time. That's another truism. Not a counter-example.


And how is superconductivity undermining any other discoveries? Mind you, by discovery is meant a new knowledge of what's real. Not just opinions, hypotheses or theories.

- Superconductivity : does it limit or expand what is possible?
- theory and application of aerodynamic lift : does it limit or make manned flight possible?
- theory of germs and bacteria and viruses : does it limit us or make diseases more diagnosable and treatable?