Black holes theorized in the 18th century

April 11, 2017
Cosmic vortex: The black hole Cygnus X-1 swallows matter of an adjacent blue giant star, emitting X-rays. Credit: Optical: DSS; Illustration: NASA/CXC/M. Weiss

Black holes are not made up of matter, although they have a large mass. This explains why it has not yet been possible to observe them directly, but only via the effect of their gravity on the surroundings. They distort space and time and have a really irresistible attraction. It is hard to believe that the idea behind such exotic objects is already more than 230 years old.

The birthplace of black holes is to be found in the peaceful village of Thornhill in the English county of Yorkshire. In the 18th century, this is where John Michell made his home, next to the medieval church. He was the rector here for 26 years and – as borne out by the inscription on his memorial in the church – highly respected as a scholar as well. In fact, Michell had studied not only theology, Hebrew and Greek at Cambridge, but had also turned his attention to the natural sciences.

His main interest was geology. In one treatise, which was published after the Lisbon earthquake of 1755, he claimed that subterranean waves existed which propagated such an earthquake. This theory caused quite a stir in the academic world, and led to John Michell being accepted as a Fellow of the Royal Society in London, not least because of this theory.

He gave a talk before this renowned society in 1783 on the gravitation of . He used a thought experiment to explain that light would not leave the surface of a very massive star if the gravitation was sufficiently large. And he deduced: "Should such an object really exist in nature, its light could never reach us."

More than a decade after Michell, another scientist took up this same topic: in his book published in 1796 - Exposition du Système du Monde - the French mathematician, physicist and astronomer Pierre-Simon de Laplace described the idea of massive stars from which no light could escape; this light consisted of corpuscles, very small particles, according to the generally accepted theory of Isaac Newton. Laplace called such an object corps obscur, i.e. dark body.

Stellar thoughts: in 1796, the French mathematician, physicist and astronomer Pierre-Simon de Laplace described the idea of ​​heavy stars from which light could not escape. Credit: Public domain

The physical thought games played by John Michell and Pierre-Simon de Laplace did not meet with much response, however, and were quickly forgotten. It was left to Albert Einstein with his General Theory of Relativity to pave the way for these "dark bodies" to enter the realms of science – without this really being his intention. Although the existence of point singularities, in which matter and radiation from our world would simply disappear, can be derived from the equations he published in 1915, 1939 saw Einstein publish an article in the journal Annals of Mathematics in which he intended to prove that such black holes were impossible.

But back in 1916, the astronomer Karl Schwarzschild had taken the Theory of General Relativity as his basis to calculate the size and the behaviour of a non-rotating static black hole carrying no electric charge. His name has been given to the mass-dependent radius of such an object, inside which nothing can escape to the outside. This radius would be around one centimetre for Earth.

Schwarzschild had a meteoric career during his short life. Born in 1873 as the eldest of six children of a German-Jewish family in Frankfurt, his talent emerged at an early age. He was only 16 when he published two papers in a renowned journal on the determination of the orbits of planets and binary stars. His subsequent career in astronomy took him via Munich, Vienna and Göttingen to Potsdam, where he became director of the astrophysical observatory in 1909. A few years later, in the middle of Word War I – Karl Schwarzschild was artillery second lieutenant on the Eastern front in Russia – he derived the exact solutions for Einstein's field equations. He died on 11 May 1916 from an auto-immune disease of the skin.

The topic of black holes did not yet find its way into the scientific domain, however. If anything, the interest in Einstein's theoretical construct diminished more and more after the initial hype. This phase lasted approximately from the mid-1920s to the middle of the 1950s. Then followed what the physicist Clifford Will called the "renaissance" of the General Theory of Relativity.

It now became important to describe objects which initially were only of interest to the theoreticians. White dwarves, for example, or neutron stars where matter exists in very extreme states. Their unexpected properties could be explained with the aid of new concepts derived from this theory. So the black holes moved into the focus of attention as well. And scientists working on them became stars – like the British physicist Stephen Hawking.

Higher mathematics: Karl Schwarzschild calculated the size and behaviour of a non-rotating and non-electrically charged static black hole in 1916, based on the general theory of relativity. Credit: Public domain

At the beginning of the 1970s, Uhuru heralded in a new era for observational astronomy. The satellite surveyed the universe in the range of extremely short wavelength X-ray radiation. Uhuru discovered hundreds of sources, usually neutron stars. But among them was one particular object in the Cygnus (=swan) constellation. It was given the designation Cygnus X-1. Researchers discovered it to be a giant star of around 30 solar masses which shone with a blue glow. An invisible object of around 15 solar masses orbits around it – apparently a black hole.

This also explains the X-rays recorded: the gravity of the black hole attracts the matter of the main star. This collects in a so-called accretion disk around the massive monster, swirls around it at incredibly high speed, is heated up to several million degrees by the friction – and emits X-rays before it disappears in the space-time chasm.

Cygnus X-1 is by no means the only black hole which the astronomers have detected indirectly. So far, they have found a whole series of them with between 4 and 16 solar masses. But there is one which is much more massive. It is located at the heart of our Milky Way, around 26,000 light years away, and was discovered at the end of the 1990s. In 2002, a group including Reinhard Genzel from the Max Planck Institute for Extraterrestrial Physics succeeded in making a sensational discovery: at the Very Large Telescope of the European Southern Observatory (ESO), the scientists observed a star which had approached the galactic centre to within a mere 17 light hours (just over 18 billion kilometres).

During the months and years that followed, they were able to observe the orbital motion of this star, which was given the designation S2. It orbits the centre of the galaxy (Sagittarius A*) once every 15.2 years at a speed of 5000 kilometres per second. From the motion of S2 and other stars, the astronomers concluded that around 4.5 million solar masses are concentrated in a region the size of our planetary system. There is only one plausible explanation for such a density: a gigantic black hole.

Our Milky Way is no exception: the scientists believe that these mass monsters lurk at the centres of most galaxies – some even much larger than Sagittarius A*. A black hole of approx. 6.6 billion solar masses is located inside a giant galaxy known as M87! Like Sagittarius A*, this stellar system 53 million light years away is also part of the observation programme of the Event Horizon Telescope.

With the discovery of gravitational waves in September 2015, the history of black holes reached its present climax. At that time, waves from two merging holes with 36 and 29 were registered. This heralded in a new era of astronomy, whose aim is to bring light into the dark universe. And also to shed light on these mysterious .

Explore further: Astronomers hoping to directly capture image of a black hole

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RNP
4.9 / 5 (11) Apr 11, 2017
For those interested, you can get an estimate the mass of the BH just using the velocity and radius of S2 given in the article. The required formula is:

GM=v²r

(where M is mass of central body, while v and r are velocity and radius of the of orbiting body.)

With R=120 AU and V=~170 times the velocity of the Sun, we get a mass of:

M = 170²* 120 = 3.5 million solar masses.

The mismatch between this number and the one given in the article is that I used just one star and have had to assume a circular orbit that is not inclined wrt the line-of-sight. This makes the number I calculate above a LOWER LIMIT.
HannesAlfven
1 / 5 (6) Apr 11, 2017
Interesting that the author managed to present the history as lacking any controversy. You might be surprised by what was left out ...

The Incoherence of Black Hole Mathematics
https://plus.goog...vSxFaszB
Tuxford
1.4 / 5 (9) Apr 11, 2017
The Black Hole concept is simply Science Porn. Sexy!
xinhangshen
1 / 5 (14) Apr 11, 2017
Though it is still a question whether black holes exist in nature, there is no doubt that Einstein's general relativity is wrong because time is absolute and independent of the 3D space. For more details disproving relativity, please read "Challenge to the special theory of relativity", March 1, 2016 Physics Essays: https://www.resea...lativity
Zzzzzzzz
4.8 / 5 (16) Apr 11, 2017
Though it is still a question whether black holes exist in nature, there is no doubt that Einstein's general relativity is wrong because time is absolute and independent of the 3D space. For more details disproving relativity, please read "Challenge to the special theory of relativity", March 1, 2016 Physics Essays: https://www.resea...lativity

I see why you are convinced - you wrote the article you linked. Your article failed to convince me. I can find nothing in it that serves as "proof" of anything. It is an argument, and not a very convincing one. Perhaps that is why you're on here advertising it....
RNP
5 / 5 (6) Apr 11, 2017
Apologies. My post above should have read:

"V=~170 times the velocity of the Earth around the Sun".
Chris_Reeve
1 / 5 (5) Apr 11, 2017
Re: "Though it is still a question whether black holes exist in nature, there is no doubt that Einstein's general relativity is wrong because time is absolute and independent of the 3D space."

Thanks for posting! You might consider joining the discussion here ...

The Aether Experiments
https://plus.goog...sfc=true
Whydening Gyre
5 / 5 (5) Apr 11, 2017
Though it is still a question whether black holes exist in nature, there is no doubt that Einstein's general relativity is wrong because time is absolute and independent of the 3D space.

I'd say - wrong. Neither is possible without the other. Now, it can be "looked" at that way, but it is still futile to do so. BTW, it is also part and parcel of 1 and 2d space as well.
For more details disproving relativity, please read "Challenge to the special theory of relativity", March 1, 2016 Physics Essays: https://www.resea...lativity

Except - you didn't do the 7th step...
Chris_Reeve
1 / 5 (4) Apr 11, 2017
Arguments for (and of course against) aether should be tracked and documented in a format which supports our ability to quickly understand the claims on both sides. And it should be done with or without the support of academics.
baudrunner
1 / 5 (2) Apr 11, 2017
– and emits X-rays before it disappears in the space-time chasm.
Excuse me? Could the writer please explain clearly what and where this "space-time chasm" is?
ursiny33
1 / 5 (4) Apr 11, 2017
Photons could be anti gravity constructions, and the alledged gravitational lensing could be the balanced charged particle construction of the photons riding the path of least resistance of the magnetic field of the galaxy which is nature in charged particle electric motion
jonesdave
4.9 / 5 (10) Apr 11, 2017
@Reeve,
And it should be done with or without the support of academics.


What, you mean with the input of f***wits like Scott and Thornhill? How will that help? Do please explain how these unqualified woo merchants might help the discussion.
jonesdave
5 / 5 (14) Apr 11, 2017
Photons could be anti gravity constructions, and the alledged gravitational lensing could be the balanced charged particle construction of the photons riding the path of least resistance of the magnetic field of the galaxy which is nature in charged particle electric motion


Jesus wept. No, gravitational lensing (which I did a thesis on) is to do with effing gravity. One can even pick out planets through gravitational microlensing (which is what my thesis was about). There is nothing sodding 'alleged' about it, you eejit. Grow up, get an education. Yes? Dear me, where do these idiots come from?
Captain Stumpy
4.4 / 5 (8) Apr 11, 2017
Arguments for (and of course against) aether should be tracked and documented in a format which supports our ability to quickly understand the claims on both sides. And it should be done with or without the support of academics.
hannes/reeve
so... without the support of academics?
https://www.merri...academic

that means, by definition, without supporting evidence because you don't want formal study or very learned people who can supply evidence supporting their claims

you want people to produce opinion - and therein lies the problem as well as the reason for the "controversy" you're discussing

when people can't actually validate their claims, like the eu cult, then it becomes pseudoscience
science requires evidence, and at any time that can be challenged by new evidence
this is why newtonian gravity was superseded

the controversy arises out of ignorance or stupidity (or belief)
not facts
Whydening Gyre
5 / 5 (5) Apr 11, 2017
Arguments for (and of course against) aether should be tracked and documented in a format which supports our ability to quickly understand the claims on both sides. And it should be done with or without the support of academics.
hannes/reeve
so... without the support of academics?
https://www.merri...cademics

Cap'n.
To be fair, he did say WITH or without...;-)
Pooua
not rated yet Apr 11, 2017
Oh, no! Religious people in science! Eek! Eek! Aaaa-u-r-g-h!
HannesAlfven
1 / 5 (4) Apr 11, 2017
Re: "What, you mean with the input of f***wits like Scott and Thornhill? How will that help? Do please explain how these unqualified woo merchants might help the discussion."

What I'm saying is that if academics refuse to document scientific controversies, it shouldn't concern anybody. Put another way, there should be no perceived need to place control over the documentation of scientific controversies under the very people who stand to lose the most from a wider public understanding of them.
Mimath224
1 / 5 (1) Apr 11, 2017
@Pooua That isn't so strange nor a bad thing either. Don't forget the ancients studied the 'heavens' etc so that they could plan for special days in thanks to their 'gods' and that's where Astronomy has its it roots. Indeed, even today we remember those times because we still use Constellations, Orion the hunter, Cetus, Perseus and so on. Many of these were named long before (what we recognize as) science came along. Issac Newton was a theologian as was Lewis Carroll, who taught maths & Logic & pioneered photography. People like R. Feynman, although may not have believed in 'god' himself, apparently thought it was impossible for science to disprove the existence of 'god'. He also thought 'god' was consistent with science (or words to that effect). I have no doubt that today many scientists believe in 'god' but the important point is how they balance and conduct themselves when pursuing the mysteries of the universe.
Da Schneib
5 / 5 (8) Apr 11, 2017
I alluded to this formulation of the concept of a black hole in the recent Milky Way black hole thread. It's very much worth mentioning that Pierre LaPlace endorsed Michell's "dark star" concept and did some more research on it.

Relativity is not necessary to describe a black hole; Newtonian Universal Gravitation can do it too. Once the escape velocity exceeds the speed of light, the results are obvious: nothing, including photons, can escape.

Michell was actually a pretty amazing guy, a real renaissance man.
wduckss
1 / 5 (4) Apr 12, 2017
Black holes are accrued due consuming large amounts of alcohol or small the use of the brain.
Physics used the evidence, without using the of evidence we have black holes and other fairy tales.
manfredparticleboard
4.2 / 5 (5) Apr 12, 2017
Mention BH theory or observations and you get them running...

Da blahk hole is mayd frahm dah 'lectric fariy dust 'n stuff, an' dis is whah da eye ensteinn is wrorng!

http/ absolutefrogturdbatshitcrazy.com.
Da Schneib
5 / 5 (5) Apr 12, 2017
Face it, guys, you don't need Einstein to prove black holes exist. Newton will do. And a little observation.
wduckss
1 / 5 (1) Apr 12, 2017
Mention BH theory or observations and you get them running...

Da blahk hole is mayd frahm dah 'lectric fariy dust 'n stuff, an' dis is whah da eye ensteinn is wrorng!

http/ absolutefrogturdbatshitcrazy.com.

Einstein and black hole? Where do you live?

xinhangshen
1 / 5 (2) Apr 12, 2017
Though it is still a question whether black holes exist in nature, there is no doubt that Einstein's general relativity is wrong because time is absolute and independent of the 3D space. For more details disproving relativity, please read "Challenge to the special theory of relativity", March 1, 2016 Physics Essays: https://www.resea...lativity

I see why you are convinced - you wrote the article you linked. Your article failed to convince me. I can find nothing in it that serves as "proof" of anything. It is an argument, and not a very convincing one. Perhaps that is why you're on here advertising it....


It is nice to see your comment. I have done numerous debates with people like you. Now it is a great time to start another debate. Please present your refutation of my points in the paper to start the debate.
JBrdgesXXX
3 / 5 (2) Apr 12, 2017
When will the science community stop calling black holes, black holes. They are not black holes. It's like you park on a driveway and you drive on a parkway. What they should be called is black spheres or black spinning mass. The gravitation force of these spinning black spheres are so great that nothing escapes it, not even the concept of what they are. If anything reaches the event horizon, they will be stretched into an orbit around a black hole, never inside a black hole. You see, the hole concept is the issue. It's similar to the gas giant to planet, planet to dwarf planet, dwarf planet to asteroid, asteroid to rock issue.
manfredparticleboard
3 / 5 (2) Apr 12, 2017
The BH idea leaves a perplexing contradiction. If nothing escapes from the 'hole', then what mediates the effect of mass on spacetime on our side of the fence? No one has given me a satisfactory answer to that one.
Da Schneib
5 / 5 (1) Apr 12, 2017
Actually, it's not correct that nothing escapes. We know of three things that do: gravity, electromagnetic fields, and Hawking radiation. Color charge is confined, so I don't expect it can; but I'd listen to a physicist who could justify it. Weak bosons are massive, so I don't expect it can either.

What's correct is that neither matter nor light can escape it.
Da Schneib
5 / 5 (1) Apr 13, 2017
@JBrdges, a rose by any other name would smell as sweet. Doesn't really matter what they call them.

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