[HN Gopher] In 1783, an English rector predicted black holes usi...
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In 1783, an English rector predicted black holes using classical
mechanics
Author : smusamashah
Score : 256 points
Date : 2021-10-28 13:46 UTC (9 hours ago)
(HTM) web link (interestingengineering.com)
(TXT) w3m dump (interestingengineering.com)
| bokchoi wrote:
| "An Inquiry into the Probable Parallax, and Magnitude of the
| Fixed Stars, from the Quantity of Light Which They Afford us, and
| the Particular Circumstances of Their Situation."
|
| Paper titles were pretty awesome back in the day.
| HeckFeck wrote:
| Not to menion lacking any pretention. It states the subject
| precisely. An honest straightforwardness with nothing to hide.
| delecti wrote:
| I don't think paper titles are usually pretentious, they're
| just dense with jargon to be terse. They're impenetrable if
| you don't know the jargon, but I don't agree that makes it
| pretentious. I don't think it's possible for a journal paper
| in an established field to be simultaneously precise,
| accessible, and unprecedented enough to be worth publishing.
| [deleted]
| whatshisface wrote:
| "Tribological behavior and wear mechanism of Ti/MoS2 films
| deposited on plasma nitrided CF170 steel sliding against
| different mating materials"
|
| "Which Milky Way masses are consistent with the slightly
| declining 5-25 kpc rotation curve?"
|
| "Characterization of systematic error in Advanced LIGO
| calibration in the second half of O3"
|
| Randomly found on arXiv and ADS. I'm not seeing a lot of
| pretention, dishonesty or imprecision.
| thebooktocome wrote:
| Drift into machine learning and you'll soon find content-
| free meme titles like "Building Rome in a day" or
| "YOLO9000: Better, Faster, Stronger".
| tux3 wrote:
| Snowclones are all you need!
| melony wrote:
| It is easy to when there are fewer academics around. Higher
| education was a privilege, tenureship was not yet much of a
| thing.
| xor99 wrote:
| I think the exact opposite, its unnecessarily embellished and
| ornate. Makes the whole thing sound so whimsical as to not be
| worth reading. I don't need a fairytale title to be
| interested in the content.
| edflsafoiewq wrote:
| "Who Turned Out the Lights?: Probable Parallax and the
| Magnitude of the Fixed Stars"
| coliveira wrote:
| This is the typical title a computer scientist would
| create.
| labster wrote:
| Gravity Considered Harmful
| IncRnd wrote:
| I'm going to title my next hack as Lightsout! See
| lightsout.com.
| fidesomnes wrote:
| found the redditor.
| rightbyte wrote:
| Try read Robinson Crusoe. The chapters titles are like "A
| ship comes to the rescue - X, Y and Z also happens".
|
| E.g.
|
| "Chapter XXVI Robinson Discovers Himself to the English
| Captain--Assists Him in Reducing His Mutinous Crew, Who
| Submit to Him"
| GreenWatermelon wrote:
| LMAO spoilers in the chapter title.
| Phiwise_ wrote:
| A massive proportion of all titles were this way. Take a look
| at fictional novels or political pamphlets some time. They're
| just three sentence long summaries and they're all
| delightful.
| vecter wrote:
| What do you think about "On the Electrodynamics of Moving
| Bodies"?
| easytiger wrote:
| I studied extensively historical scientific original documents
| for several years and I tend to find my self writing very much
| in that style when I do anything that requires significant
| exposition.
|
| Even if it's something boring like remediation of a building
| structural issue.
| sbayona573 wrote:
| Read "English rectum predicted black holes" for a sec
| johnklos wrote:
| Not about the article's content, but about the
| interestingengineering.com web site: it sucks. It consumes 100%
| CPU, tries to play multiple videos, and takes hundreds of
| megabytes of memory.
|
| No, thank you.
| bsenftner wrote:
| I can see an interesting and controversial entertainment series
| based on an alternative history retelling of Einstein, in his
| role as patent clerk, reading John Michell's work and that is the
| seed which inspires Relativistic Theory. Tie the work of Mitchell
| and his world to Einstein's. The juxtapositions of time and
| culture, British 1770's versus Germany's early 20th century would
| be quite entertaining on their own.
| nyc111 wrote:
| This must be the same John Michell who gave Henry Cavendish his
| pendulum to measure the density of the Earth :
|
| ,,Many years ago, the late Rev. John Michell, of this Society,
| contrived a method of determining the density of the earth, by
| rendering sensible the attraction of small quantities of matter;
| but, as he was engaged in other pursuits he did not complete the
| apparatus till a short time before his death, and did not live to
| make any experiments with it. After his death, the apparatus came
| to the Rev. Francis John Hyde Wollaston, Jacksonian Professor at
| Cambridge, who, not having conveniences for making experiments
| with it, in, the manner he could wish, was so good as to give it
| to me.,,[1]
|
| [1]
| https://royalsocietypublishing.org/doi/10.1098/rstl.1798.002...
| akvashi wrote:
| Pretty cool that this black mathematician is getting recognition
| now!
| sillysaurusx wrote:
| Whoa, he is indeed black:
| https://en.wikipedia.org/wiki/John_Michell
|
| > There is no surviving portrait of Michell; he is said to have
| been "a little short Man, of a black Complexion, and fat".
|
| Awesome!
| whimsicalism wrote:
| Don't know that we can really read contemporary understanding
| of the word black into this quote. I think given the context
| of England at the time, as well as the description of his
| family background, it is very unlikely that he was black.
| tarkin2 wrote:
| Between statistics and the description of the man, I find
| it difficult to be as sure as you are.
| whimsicalism wrote:
| It wasn't until 1786 that the British government first
| employed one of the (relatively few) black men in a minor
| role, yet I'm supposed to believe based on a contemporary
| reading of this text (before "black" was nearly widely
| used to mean what it does today) that this (at least 3rd
| generation) British professor at Cambridge was black?
|
| Highly doubtful. I'm not sure what statistics you are
| basing off of.
|
| Here's a more reputable source than me:
|
| > An account apparently purports him to be "a little
| short man, of black complexion, and fat", though we have
| been unable to locate any specific contemporary source.
| However, such words even if used do not necessarily
| indicate he is of black-African descent, as the term can
| refer also to Spaniards, Italians, Greeks, Arabs,
| Ethiopians, or Jews. Jonathan Swift uses the expression
| "a tall, thin, very black man, like a Spaniard or Jew."
| In the given context it is almost certainly intended as a
| slight against Michell by painting him as something he
| was likely not. The Royal Society famously refused
| election to Jamaican scientist Francis Williams
| (1702-1770), on account of his complexion, and it almost
| certainly would not have elected a black man as early as
| 1760. Moses Da Costa became the first Jew elected to the
| Society in 1736, and a second was elected in 1747; the
| first female was not elected until 1945. The earliest
| black individual we could determine that attended Queens
| College, Cambridge was an American, Alexander Crummell,
| who graduated 1853.
| tablespoon wrote:
| > Here's a more reputable source than me:
|
| Care to give a citation?
| whimsicalism wrote:
| Okay, on second glance I appear to give undue weight to
| things with footnotes.
| https://www.nndb.com/people/607/000107286/
|
| The reasoning in general makes sense, and the evidence
| they bring to bear re: Swift is somewhat convincing to
| me.
| tablespoon wrote:
| The main text of that entry appears to be a slightly-
| reworked version of the public-domain 1911 Encyclopaedia
| Britannica, but the Google Books image doesn't have the
| footnote you quoted. I'm guessing it's original to that
| NNDB site, which probably started with the encyclopedia
| like Wikipedia did.
|
| https://www.google.com/books/edition/The_Encyclopaedia_Br
| ita...
| sillysaurusx wrote:
| I was wondering about that. Is there a way to verify? It
| would be really interesting if he were, and it would be
| equally interesting if there was some way to show
| conclusively that he wasn't.
|
| It's a tricky subject, but it must be possible to approach
| it with scientific curiosity and clinical detachment...
|
| What did a black complexion mean back then?
| whimsicalism wrote:
| > What did a black complexion mean back then?
|
| Black people were very rare in Britain at the time, this
| term was used very broadly for people like Italians,
| Iberian descent, jews, etc.
|
| I doubt there is any way to show "conclusively" that he
| wasn't, but I would say the evidence is pretty strongly
| against. Someone I quoted in another reply provide more
| reasoning on what that evidence is.
| tablespoon wrote:
| A good place to start would be:
|
| 1. How would an English clergyman in the first half of
| the 1700s typically describe someone who was of African
| descent? This appears to be the guy who wrote the
| description:
| https://en.wikipedia.org/wiki/William_Cole_(antiquary).
| My intuition is that the _wouldn 't_ just use "black,"
| but would probably use something more specific, like
| "African" or "negro."
|
| 2. At that time, would a "black" person (in the modern
| sense) have been accepted into the kinds of positions
| John Michell had (like being a member of the Royal
| Society), with so little comment on his race?
| [deleted]
| monknomo wrote:
| dark hair, brown eyes and and something around a tan
| would probably constitute "black"
|
| Swedes were described as swarthy by Ben Franklin, so the
| conception of what black and swarthy are don't really
| line up to the modern meanings
| tablespoon wrote:
| > Whoa, he is indeed black:
| https://en.wikipedia.org/wiki/John_Michell
|
| >> There is no surviving portrait of Michell; he is said to
| have been "a little short Man, of a black Complexion, and
| fat".
|
| Only if you assume that describing someone as having a "black
| Complexion" sometime between 1731-1764 has the same meaning
| as if an American used phrase in 2021 (e.g. having Sub-
| Saharan African ancestry). I think there's a fairly high
| likelihood that assumption is wrong.
|
| The wikipedia cite identifies the source as "Cole MSS XXXIII,
| 156, British Library", which appears to be this http://search
| archives.bl.uk/primo_library/libweb/action/disp...
|
| > 43. Account of the Woodwardian professors of fossils, at
| Cambridge, viz. Dr. Conyers Middleton, Dr. Charles Mason, Mr.
| John Michel, and Dr. Ogden, 1731-1764. pp. 156, 157.
| teakettle42 wrote:
| The meaning of "black complexion" at the time was simply
| "dark hair and eyes".
| sillysaurusx wrote:
| Very interesting, thanks.
| bunabhucan wrote:
| This [1] has a good description of a jamacian student in Queens
| College in the 1700s.
|
| [1] https://www.blackpast.org/global-african-history/people-
| glob...
| [deleted]
| marcodiego wrote:
| Speed of light can be calculated using only classical mechanics
| and experiments. Same for gravity and gravitational constant.
| Predicting relativistic effects of high speeds and huge masses
| that is another thing.
| jagrsw wrote:
| Isn't it a bit like getting to correct answer by incorrect
| reasoning? I was thinking that knowledge of how space curves in
| presence of high energies/masses and time/length dilation
| concepts are necessary to come to the conclusion that light will
| be slowed down beyond its speed in certain circumstances?
|
| Maybe a bit similar to e.g. Gordiano Bruno's claim that stars are
| similar to our sun, and there are planets around them, not on the
| basis of observations and data analysis but b/c of some
| relatively unrelated to astronomy philosophical reasoning.
|
| Also, alchemy :) (some concepts were right)
| zinclozenge wrote:
| Not really. You can predict gravitational light bending with
| newtonian physics and a corpuscular approach to light. It gives
| you half the value of the relativistic value because the
| assumption is that light as a wave is unaffected by gravity due
| to no gravity-EM coupling.
| jetrink wrote:
| I don't think the reasoning is incorrect. It went like this:
|
| 1. What if the motion of light is influenced by gravity, as
| suggested by Newton's theory of corpuscles? (It is, just not in
| the way he thought.)
|
| 2. And what if there are supermassive, super-dense objects?
| (Turns out there are.)
|
| 3. Then light would be unable to escape such objects.
|
| That's pretty remarkable in my opinion, and no more "wrong" in
| its way than Newton's theory of gravity which was also correct
| for the wrong reasons.
| [deleted]
| Moodles wrote:
| I suppose it's impossible to ever really know what the true
| nature of reality is. We only have models which have an
| accuracy of x%. It's quite possible, dare I say likely, that
| e.g. quantum mechanics as we understand it today is just an
| approximate model of how things really are. I suspect that the
| fundamental nature of reality is probably at a scale too small
| to be testable anyway.
| AltoidsTin wrote:
| > incorrect reasoning
|
| If you haven't already, check out the Demarcation Problem and
| work by Feyeraband. Physics is such a philosophically tenuous
| science that its theories are perpetually incorrect reasoning.
| IncRnd wrote:
| What was the incorrect reasoning?
| Enginerrrd wrote:
| I can't say for sure on this particular case, but the usual
| reasoning is this:
|
| Using Newtonian Mechanics (I'll skip the derivation.) you can
| calculate escape velocity as follows: v = sqrt(2GM / r)
|
| r is the distance to the center of mass, G is the usual
| gravitational constant and M is the mass of the body.
|
| So, now we can reason about an object whose escape velocity
| is c.
|
| c^2 = 2GM / r and rearranging a bit:
|
| r* = 2GM / c^2.
|
| Thus, IF we packed a mass M into the radius r*, we would have
| a Newtonian blackhole.
|
| It turns out, quite incredibly, that this r* is in perfect
| agreement with the swarzchild radius from a non-rotating
| blackhole calculated using general relativity. Exactly why
| these two are in such agreement has never been explained to
| me other than as a coincidence. But it's quite incredible
| since usually r^3 terms pop up prior to the event horizon (at
| the same radius) which make GR make different predictions
| about orbits. (Such as the precession of mercury)
| vanderZwan wrote:
| > _(some concepts were right)_
|
| I would expect a lot of incorrect past models of science and
| its precursors to still be based on (mostly) correct data, so
| bad guesses were still informed bad guesses at least.
| pdabbadabba wrote:
| We should bear in mind that, if the history of science is any
| guide, in 250 years' time relativity will probably seem pretty
| badly flawed as well leading some future person to criticize
| _our_ science for "getting to a correct answer by incorrect
| reasoning." (If we're lucky. It might just seem wrong.) So we'd
| do well to be charitable in crediting our predecessors'
| achievements.
| soheil wrote:
| Completely agree. It's a textbook example of hindsight bias
| when people cannot "unsee" the currently accepted theory
| deemed to be "true" and fail to imagine that people in the
| past thought just like them before the new theory came along.
| I think it takes a good amount of marketing (eg. Einstein
| with Relativity) to change people's mind if a new improved
| theory is to be accepted and for majority to conform to it.
|
| So let's indeed be very charitable in crediting our
| predecessors' achievements.
| mr_mitm wrote:
| What do you mean by marketing? Einstein didn't need much
| convincing, as he proposed experiments that would falsify
| or confirm general relativity. The theory is also not only
| mathematically sound but very elegant. Acutally, Hilbert
| arrived at the same equations using a competely different,
| more mathematical approach using the least action
| principle, which is another good sign it was correct. But
| the smoking gun was of course Edison's observation of
| gravitational lensing during an eclipse.
|
| But of course the topic in this subthread is special
| relativity. And I think the speed of light being constant
| and a maximum speed is one of the most fundamental and most
| assured fact about the universe that we know, because it's
| more than just some speed of some particle. It's a
| geometric property of spacetime, a Lorentzian manifold. I
| doubt it will ever be looked upon as some sort of horrible
| blunder, just like no one ever thinks less of Newton just
| because he only found an approximately correct theory. I
| think it's foolish to doubt it just to be contrarian.
|
| Could it be wrong? Sure, we look for violations of Lorentz
| invariance all the time. But the boundaries we have on it
| are extremely good. But if someone claims to have observed
| superluminal speeds, I'll doubt the experimenters more than
| I'll doubt special relativity, because of the strong priors
| we have on it. This happened by the way a few years ago,
| where some Italian lab claimed to have seen superluminal
| neutrinos. Most professional physicists didn't believe it.
| It turned out to be a faulty cable.
| raattgift wrote:
| > Edison's observation of gravitational lensing during an
| eclipse
|
| There may have been electric lights and phonographs on
| the ships, but it was the
|
| https://en.wikipedia.org/wiki/Eddington_experiment
|
| and while maybe you could say it was about gravitational
| lensing, the observatories (and Earth) was so far from
| any possible caustic that it's better to leave it at just
| deflection of light.
|
| Here's a pop-sci treatment of the gravitational lensing
| of our sun for astronomy -- tl;dr it involves lonnnnng
| distance travel, more than 500 astronomical units (Pluto
| is at ~ 30-50 au).
| https://blogs.scientificamerican.com/observations/using-
| the-...
| joe__f wrote:
| Your comment seems to imply that, for example, the current
| consensus is that Newtonian gravity is 'pretty badly flawed'
| now that we understand it to be superseded by general
| relativity. This is not true; Newtonian gravity is considered
| to be a very good approximate theory for low velocities and
| field strengths.
| lapetitejort wrote:
| Relativity will probably suffer the same fate as classical
| mechanics: true for small values of _v_. In relativity 's
| case, the small value will probably be about 0.99999999 _c_.
| tsimionescu wrote:
| Given what we know today, it seems that it's much more
| likely that special relativity will remain more or less as
| we know it today (a good approximation for relatively flat
| regions of space-time and non-accelerating bodies), and
| that GR will be a good approximation for something like
| large regions of space-time and huge masses (where "large
| regions" may mean anything larger than a few Planck
| lengths, and "huge masses" may mean anything greater than a
| few micrograms).
| raattgift wrote:
| > non-accelerating bodies
|
| Accelerated bodies in flat spacetime (Minkowski space)
| are well-described by special relativity. One can even
| calculate usefully in accelerated reference frames. https
| ://en.wikipedia.org/wiki/Acceleration_(special_relativi..
| .
|
| The Unruh effect can happen in flat spacetime, for
| example, and is a useful check on Hawking radiation (in a
| black hole curved spacetime).
|
| It's also interesting in understanding the weak
| equivalence principle in detail; very loosely, a small-
| mass object can rest quietly on the surface of a non-
| compact, non-spinning, spherical mass eternally, while it
| is at least very difficult to keep the same small-mass
| object accelerating uniformly in flat spacetime for even
| fairly short (compared to say the age of the universe,
| which is hardly eternal) finite times.
| soheil wrote:
| Quantum Mechanics most likely is not the true explanation of
| what is going on either, but it sure as hell accounts for a lot
| of it and is why we have modern computers.
| roywiggins wrote:
| The corpuscular theory of light was one of those theories that
| was wrong but useful. The successor wave theory was _also_
| wrong. It may turn out that general relativity is founded on
| incorrect reasoning ( "God does not play dice" for one), but
| that matters much less than it being fantastically useful.
|
| The basic idea- if light interacts with gravity, if you pack
| enough mass into a region you will get a dark star- is correct.
| It just turns out that the interaction can't be described by
| treating light as little particles and calculating by Newton's
| equations.
|
| There's been lots of wrong-but-useful theories, like phlogiston
| or arguably luminiferous aether:
|
| https://thonyc.wordpress.com/2015/10/23/the-phlogiston-theor...
| whatshisface wrote:
| It's not founded on incorrect reasoning, which would imply a
| logical inconsistency or error in the deductions, but it
| could be founded on false postulates. (A postulate is like an
| axiom except that it is held to be true in the real world, as
| opposed to being abstractly true.)
| sillysaurusx wrote:
| That's true of all science since the beginning of science.
| dav_Oz wrote:
| The "dark star" hypothesis given a finite speed and momentum of
| light (particle nature) combining with the escape velocity of
| stars isn't impressive by itself.
|
| But his scientific reasoning and methods very much so. He
| carefully conjectured what could be observed e.g. binary stars in
| amassing data points. Naturally, in a logical progression, he
| looked for stars which behaved as if they were in a binary
| systems but the partner i.e. "dark stars" could not been seen
| because its mass would be so big that the finite speed of light
| couldn't "escape". Brilliant.
|
| He, also, inherited Cavendish his "torsion balance" apparatus for
| measuring the mass of the earth for what later became the famous
| "Cavendish experiment" yielding an accurate measurement of the
| gravitational constant. The experimental basis for the
| advancement into the nature of gravity.
|
| Quite impressive.
|
| And he did not yell about it or seemed to care about what
| nowadays would be called the "impact factor".
|
| His impact was quite of another nature.
| hirundo wrote:
| s/inherited/bequethed
| groos wrote:
| s/bequethed/bequeathed
|
| :-)
| tomrod wrote:
| Not related to the discussion, but I love these verbal
| dualities.
|
| give/take
|
| inherit/bequeath
|
| and so forth!
|
| -------
|
| What fantastic reasoning! I am constantly amazed at the
| early and current astronomers, able to work out fairly and
| increasingly accurate cosmological views from pinpoints of
| light.
| argomo wrote:
| Give/take duality is significant in the study of proto-
| indo/european language. IIRC, some root words took
| opposite meanings in their descendent languages. Some
| have gone so far as to speculate that this suggests
| reciprocality was an important culture expectation around
| gift-giving in PIE society.
| robocat wrote:
| In New Zealand 'borrow' can be used to mean lend
| (transitively).
|
| 'I will borrow you that book' means I will lend it to
| you, just to give an example of a word changing to its
| opposite meaning.
| diroussel wrote:
| Borrow is used like this some times in working class
| England too. But this form is frowned upon in more
| 'educated' circles.
| jacquesm wrote:
| Same in Dutch. 'Ik leen geld van de bank. De bank leent
| geld aan mij.'
| verve_rat wrote:
| I'm a Kiwi. I've never heard it used like that?
| foldingmoney wrote:
| likewise.
| Misdicorl wrote:
| Also super common in northern Wisconsin
| patrickk wrote:
| Perhaps because of the German influence?
|
| Anecdotally, today in Germany, it's really tricky for
| Germans with a very strong grasp of English to
| distinguish between 'borrow' and 'lend'.
| [deleted]
| mach1ne wrote:
| The thing is, academia has always been rather dumb at its main
| job; analyzing the validity of research. Meaning that, even if
| the research proves its validity on its own, academia fails to
| pick it up, preferring to wait for secondary proofs.
|
| It takes a certain kind of a person to go against the flow.
| Einstein certainly did and it sure wasn't a smooth ride. Even
| in our days, Geoffrey Hinton wasn't allowed to present on deep
| learning in AI conferences in the early 2000's, even though the
| exact same theoretical bases existed then as they do now.
| legohead wrote:
| How does a black hole trap light if it's not by gravity, is it
| purely by space curvature?
| ketralnis wrote:
| From a newtonian perspective you can imagine that gravity emits
| a force between all pairs of massive objects. That's a good way
| to look at it for small values of mass. It works pretty well on
| the scale of our whole solar system. This is what you're
| imagining when you say "not by gravity but by spacetime
| curvature".
|
| But gravity _is_ spacetime curvature. It is manifested by
| changes to spacetime itself made by that mass. For very large
| values of mass (or density in this case) that newtonian
| approximation doesn 't hold according to experiment. We need a
| different model and the model that we've found that works is
| that mass changes the shape of spacetime. Its presence changes
| the nature of straight lines and the paths that you can follow
| (geodesics).
|
| A black hole causes all possible paths of spacetime, paths that
| light must follow because it travels through spacetime, to
| point into the black hole
| https://en.wikipedia.org/wiki/Black_hole#Event_horizon Light
| must follow straight lines but because the _space_ containing
| those lines is curved, there don 't exist any of those lines
| that point outside of the black hole. Once you've crossed the
| event horizon, space itself doesn't have any straight lines
| that point outward, there are no paths that you can follow.
|
| It's even weirder than this because we're mostly familiar with
| motion through space so that's probably what you (and I) are
| imagining, but this is motion through spacetime. So really the
| correct thing to say is that there exist no 4-d paths that
| point outside of the black hole that are also in the future.
| And _that 's_ even weirder than it sounds because you asked
| about light specifically and light doesn't experience time the
| same way you and I do. So our intuitions and our ability to map
| reality to the nice charts that we're used to looking at are
| pretty limited here.
| legohead wrote:
| Very cool answer, thank you!
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