Szydagis' point 3: Interstellar travel is too hard

"... would be thrilled if we would find some way of talking about all of standard physics, not just the toy models that we're looking at, but all the standard physics in a way that doesn't put spacetime in and doesn't put quantum mechanics in, and gets the answers out. And ultimately then, if we really understand it, then we'll have the beginning of an understanding, a starting point, from which we can see the emergence of spacetime and quantum mechanics

Fascinating. I wonder though how that undoubtedly interesting theory dealt with the reality experimentally proved by the Nobel Prize winners Alan Aspect, John Clauser y Anton Zeilinger that the classic laws of Standard Physics present clear flaws when it comes to determine the full way Nature behaves, in such a way that one definitely CAN'T get the answers out by NOT putting in quantum mechanics.
 
Fascinating. I wonder though how that undoubtedly interesting theory dealt with the reality experimentally proved by the Nobel Prize winners Alan Aspect, John Clauser y Anton Zeilinger that the classic laws of Standard Physics present clear flaws when it comes to determine the full way Nature behaves, in such a way that one definitely CAN'T get the answers out by NOT putting in quantum mechanics.

One of us has misunderstood @LilWabbit. I see the bit you quoted as saying that if you can derive QM from it, then you don't need to put QM into it.
 
Nothing prevents us from building a particle accelerator in space, and accellerating massive objects (such atomic nuclei), very close to the speed of light.
I'm not sure I understand your question, your stack-overflow link which violates the no-click policy shows a mistaken point of view being corrected, but what you appear to have asked is countered by my response. ANy CRT monitor in any space mission was a primitive particle accelerator that would almost certainly have beamed particles at relativistic speed (it depends on the voltage, obviously, but 0.01c is trivial, and 0.1c is possible).

Whether a body can accelerate *itself* (in contrast to "an object" above) to relativistic speeds is probably the question you were looking for an answer to, and that's been answered here and on SE.
I agree. I did mean with fuel self contained with capsule. But I have done some initial calculations, and it appears possible. So I retract.

[... I am trying to calculating the mass of the fuel to get capsule of mass m to pc, p being percent ...]
 
This point about time and distance that he makes really smells of getting tied up in the details and missing the picture.

I'm fairly certain that his actual rebuttal to vast distances and times is that it doesn't matter. It's essentially that send something travelling in space and given enough time it will travel a distance. As long as there's enough time in the past for something to have travelled a distance then there's the possibility that something has travelled that distance. Yes, the distances are vast but there's enough time for them to be travelled. That's it.

There's no point getting bogged down in % of c because even he says that argument is moot (just use a computer instead).

But I don't think that's the real issue with distance and time. Like sure, I could travel to Andromeda and be alive (given his maths but I do wonder what decelerating does to the dilation), but there's every chance I could be the last human in the universe by the time I get there. I have no way of finding out if I am either. What am I doing there? What was the plan?

And if you want to subscribe to the idea that physics problems MIGHT be solved at some point then time is VERY important. You run into that whole someone else sent 1 million years after me might beat me there issue (can't remember who's to credit for that paradox idea but I do like it).
 
His faith in the "we'll solve it some day" solution smacks of "turning base metal into gold".
Not necessarily a great example - you can bombard lead in a particle acceperator and get gold. Then again, the yield's terrible for the cost, and perhaps that's a feature that future theoretical tech might also suffer from too, so it might be a great example! (Not knowing the future tech, or its cost, makes that undecidable as yet.)
 
Not necessarily a great example
it's a reference to the Philosopher's Stone
Article:
The philosopher's stone or more properly philosophers' stone (Arabic: ḥajar al-falāsifa, Latin: lapis philosophorum), is a mythic alchemical substance capable of turning base metals such as mercury into gold (chrysopoeia, from the Greek χρυσός khrusos, "gold", and ποιεῖν poiēin, "to make") or silver. It is also called the elixir of life, useful for rejuvenation and for achieving immortality;[1] for many centuries, it was the most sought goal in alchemy.

Except for an unproven theory about ancient electroplating (discussed elsewhere on Metabunk), this alchemical marvel was always thought possible, but never was—just like interstellar/intergalactic travel might be.
 
This thread got me to thinking. I've been trying to put my finger on the exact nature of the problem that I've felt seriously plagues the standard ufological argument which reads roughly along these lines:

'The superior intelligence of aliens and interdimensional beings can surely explain the performance of feats that, for us, seem to violate our limited understanding of physical laws.'

This argument is not entirely without logical merit. But it entails a problem that I've 'felt' as intuitively compelling but haven't really had an opportunity to analyze more seriously. So here goes.

(1) Whatever is describable using man-made physical categories and predicates -- such as ‘beings with bodies’, ‘spacecraft’, ‘form’, 'shape', ‘motion’, ‘light’, ‘intelligence’, ‘dimension’, 'spacetime', 'matter', 'gravity', 'mass', 'negative', 'positive', 'quantity', 'energy', 'force', 'power', 'heat', 'consciousness', 'propulsion', and even the notion of 'existence' itself -- is humanly knowable at least to the extent of these categories.

(2) If we are to accept these humanly known physical categories in our description of aliens, it would be intellectually dishonest and logically problematic not to accept, by the same token, the humanly known physical laws applicable to the mentioned categories.

(3) But if we still choose not to, then the self-same intellectual honesty and logic dictates we must also cease to refer to these beings, their crafts and their behaviours by means of any known physical categories.

(4) Otherwise we're merely moving goal-posts to avoid reasoned critique, and using physical categories selectively to the extent they serve us while ceasing to use them when they get us in trouble with real science.

All of science fiction uses known physical categories, which is perfectly acceptable. That's why we call it science fiction. We just don't pretend it's science fact.
 
2) If we are to accept these humanly known physical categories in our description of aliens, it would be intellectually dishonest and logically problematic not to accept, by the same token, the humanly known physical laws applicable to the mentioned categories.

(3) But if we still choose not to, then the self-same intellectual honesty and logic dictates we must also cease to refer to these beings, their crafts and their behaviours by means of any known physical categories.
I agree with most of your post, but I think we lack the vocabulary to discuss the subject at all without falling back upon known terms and categories, don't we? How can any description of phenomena be transmitted to another person without describing them in terms that are familiar to both? Intellectual honesty, I agree with, but a change in vocabulary is window-dressing that would just muddy the waters.
 
(2) If we are to accept these humanly known physical categories in our description of aliens, it would be intellectually dishonest and logically problematic not to accept, by the same token, the humanly known physical laws applicable to the mentioned categories.
You seem to never have read a fantasy novel?
All of science fiction uses known physical categories, which is perfectly acceptable.
Such as Light Sabers. We know what they do, even though it's impossible for them to do it. There is no known physics to describe what they do. There is no "humanly known physical law" that applies to them even though they're perfectly described in common terms: a sword with a blade made of light.

'The superior intelligence of aliens and interdimensional beings can surely explain the performance of feats that, for us, seem to violate our limited understanding of physical laws.'
Could we do this with time travel? Find one thing or three that is possible now, that an educated person at a certain point in the past would have considered absolutely impossible (such as a perpetuum mobile)?

Because I'm not at all convinced that this reasoning has merit.
 
I agree with most of your post, but I think we lack the vocabulary to discuss the subject at all without falling back upon known terms and categories, don't we?

Indeed, but the point is the selective usage of physics vocabulary when it suits the narrative and happily withdrawing into science fiction when actual physics starts creating problems for the narrative.

For example, the ufologist will claim a spacecraft is featured in a UAP video as a radar return, moving 24 kilometers in one second, starting and ending with zero speed. He also accepts that craft has 'mass' and appears as a 'radar return'. Then, by the same token, he should accept that such a craft, in order to perform such a feat, must generate a superhot fireball and a sonic boom audible at a great distance from the craft far exceeding the radar horizon. But since the only physical track the craft leaves is a radar return, the ufologist withdraws into science fiction to explain away the absence of other necessary measurement outcomes of such a fast-moving object with a mass. If he can explain them away by a rigorous scientific argument that's testable, then we'd be on the cusp of learning something new and should happily welcome his analysis.

I like Mendel's lightsaber analogy. A 'Lightsaber Believer' (LB) will just shrug off the physics-defying bit of the saber by appeal to 'superior intelligence/technology' whilst he is more than happy to accept many other physical properties applying to the lightsaber. The debunker would be happy if the LB would either (1) claim the whole lightsaber in its entirety is some astral non-physical 'object' (in which case we bypass science altogether and agree to end the conversation right there) or (2) honestly accept lightsabers are just science fiction which is sometimes fun to indulge in. But the LB does neither and insists the lightsaber is a scientific fact. Hence the problem articulated in my 4 points earlier.

To recap, you can't involve physics in a serious scientific claim while being conveniently selective about how it applies and to what extent.
 
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Let me be clearer and formulate the Ufologistic Fallacy, which is related to the idea of advanced technology being indistinguishable from magic:

The Ufologistic Fallacy

Superintelligence implies supernatural powers.


The Problem: The assumption of an existence of a superintelligent natural being does not logically imply a supernatural being.

Hypothetically, a superintelligent natural being is a creature of our universe, part of the same natural order of things as we are and similarly subject to its fundamental constraints. Hypothetically, a supernatural being is above the natural order of things and able to avoid or manipulate its fundamental constraints.

Resolution of the Fallacy: The ufologist restricts the discussion to a superintelligent natural being which allows us to carry on a rational and scientific dialogue on the basis of scientifically testable physical laws, constants and theories. Or the ufologist accepts these beings as supernatural which allows us to stop all scientific dialogue in its tracks, and thereby saving us from getting caught up in pointless belief-based speculations.
 
To recap, you can't involve physics in a serious scientific claim while being conveniently selective about how it applies and to what extent.

I think I'd frame my view more as:
If you're introducing something that trashes our current understanding of the laws of physics, there's no merit in identifying properties that are in agreement with our current, but now trashed, understanding of the laws of physics.

More briefly: You don't get to trash the laws and still use them.
 
More briefly: You don't get to trash the laws and still use them
Dark matter/dark energy don't follow the known laws of physics, although their effects can be described in terms of known physics—that's how we know they exist.

The "either all of physics, or none of it" approach is not fruitful for discovery.
 
Dark matter/dark energy don't follow the known laws of physics,

Do you realize what you just claimed? Now, please specify which known laws of physics dark matter/dark energy do not follow?

You said "the" which implies all of them. The onus is on you to now demonstrate how dark energy doesn't follow for instance the law of conservation of energy or the various laws axiomatized in general relativity which the hypothesis of dark energy employs?

although their effects can be described in terms of known physics—that's how we know they exist.

We don't. Dark energy is a decent hypothesis but it's still only a hypothesis.

The "either all of physics, or none of it" approach is not fruitful for discovery.

How is "I will accept some physics but will ignore other bits that don't agree with my beliefs"?
 
Dark matter/dark energy don't follow the known laws of physics, although their effects can be described in terms of known physics—that's how we know they exist.
All we know about what we call "dark matter" is what we imply by known physics. You're being premature in your assessment when you claim it follows some other set of laws.
 
Dark matter/dark energy don't follow the known laws of physics, although their effects can be described in terms of known physics—that's how we know they exist.

The "either all of physics, or none of it" approach is not fruitful for discovery.

Dark energy was known to Einstein, he just didn't call it that. To him it was a parameter in an equation. He later regretted it, and took it back out again, because there wasn't enough data to be sure, and so 0 the value he felt happiest with. The value of that parameter still isn't known, it still might be 0, we've not excluded that. That doesn't mean it doesn't "follow the known laws of physics".

Dark matter doesn't break the known laws of physics either at the macroscopic scale - which are the effects we are talking about. Dark matter's interaction with us is *known*, acccording to the current laws of physics, to very high accuracy, to be incredibly low. So it will never be a component of a space-ship, or an energy weapon, or a tractor beam, or a communication device, or anything that will ever interact with us at all. We might not have the first clue what dark matter is, but that doesn't mean we haven't worked out upper bounds on certain properties it must have.

If the Bogonauts from the planet Phut shoot you with their ziggawatt sterile neutrino gun - you won't even notice it.
 
All we know about what we call "dark matter" is what we imply by known physics. You're being premature in your assessment when you claim it follows some other set of laws.
I'm assuming that if it followed all known physics, we'd have found it by now.
 
Do you realize what you just claimed? Now, please specify which known laws of physics dark matter/dark energy do not follow?

Dare anyone ask whether muons follow the known laws of physics?

(Spoiler: they do not, this is experimentally confirmed to "convincing" levels of certainty (over 4 sigma), however, this anomaly seems absolutely unimportant to the evolution of the universe around us.)
 
Dare anyone ask whether muons follow the known laws of physics?

(Spoiler: they do not, this is experimentally confirmed to "convincing" levels of certainty (over 4 sigma), however, this anomaly seems absolutely unimportant to the evolution of the universe around us.)

Muons deviate from the predictions of the Standard Model of Particle Physics which is not a law but a theory.
 
Muons deviate from the predictions of the Standard Model of Particle Physics which is not a law but a theory.
I was being informal with my use of the word "law". I know philosophers have tromped into the fields of science and scattered variously both precise and simultaniously contradictory definitions of that word all over the place, so much so that it's started to become meaningless.

Pretend I said "rules" rather than "laws". I mean the things that are codified to be predictive, not mere conclusions from observations. I've never demanded that the theories of physics (Ugh - does anyone ever utter that phrase? No. They say "the laws of physics". Don't mess with both language as well as science, your inputs are not useful in either field.) be explanatory - have you really never heard the phrase "shut up and calculate" - how explanatory is that trying to be?

It looks like your semantic sophistry has even confused Steven Weinberg!

Dreams Of A Final Theory: The Search for The Fundamental Laws of Nature
Steven Weinberg
Random House, 31. aug 2010 - 272 pages

An understanding of nature's final laws may be within our grasp - a way of explaining forces and symmetries and articles that does not require further explanation. 'This starting point, to which all explanations can be traced, is what I mean by a final theory', says Steven Weinberg in this extraordinary book. In it he discusses beauty, the weakness of philosophy, the best ideas in physics and the honour of accepting a world without god.
Content from External Source
-- https://books.google.ee/books?id=OLrZkgPsZR0C&redir_esc=y

Oh - "the weakness of philosophy" - shots fired!
 
Pretend I said "rules" rather than "laws".

Thank you. I will take that as a grumbling concession. :cool:

Unlike theories which normally seek to provide deeper and broader explanations to observed phenomena, laws of physics (in the strictest sense) are essentially exceptionless regularities. They are universal generalizations (UG, an inference rule in predicate logic) from thousands of observations, amassed throughout the history of physics, that have repeatedly and consistently displayed certain conditionalities ('if x, then y' properties) under widely differing contexts. Over the course of time, owing to their seeming inviolability, they have become validated as 'laws'.

If, however, UG is applied simplistically, these generalizations are vulnerable to what is called 'the Johnson-Carnap continuum': (infinite) universal generalizations have zero probability.

In other words, not only is it the obvious case (taught in almost every introductory course of first-order logic) that a consistent finite number of black raven observations, no matter how numerous, does not logically follow that all future ravens observed will be black. But, in fact, having observed n black ravens, it logically follows from k successive applications of the rule of succession that the probability the next k ravens are also black approaches zero as the succession tends to infinity.

This elegant argument, however, is premised on infinite succession. It stumbles upon non-zero probabilities in actual physics, inherently associated with a finite succession of confirming observations resulting in 1 (100 % probability). Take the following formulation of the Law of Conservation of Energy as an example:

In a closed a system the total energy of the system is conserved.

This law is a logical inference from thousands upon thousands of observations whereby, invariably, 'the more closed the physical system, the more it conserves energy'. If we assume, as seems reasonable, that the universe has a finite number of systems (despite being an enormous number), then every new observation of energy-conservation being conditional upon a system's level of openness further confirms the Law of Conservation of Energy. Every single positive instance increases the probability of the law applying to future instances closer to 1. This conclusion can be made even before applying your favourite Bayesian models that add further credence to the law.

Here is a good analysis on UG and its proper application for those who wish to geek out on philosophical logic further.

Oh, "philosophy strikes right back".
 
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