Laplace, Black holes etc

[Peter Pedant]

Can anyone give me the reference, chapter and verse,
about where he predicts Black Holes way back in 1799 ?
.
It is somewhere in Exposition of the Solar System
The ref I had was page 305 but it is nowhere near that.

French wiki gives the quote but not the ref.

Oh and in return for free - Laplace also predicts dark matter - vol 2 p 300 or thereabouts,he points out there may be stuff outthere doing its gravitational bit thatwe cannnot see ('invisible/opaque')

But he does get some things wrong wrong wrong
he estimates (as in, 'I have calculated....') the speed at which gravity acts, as several thousand times the speed of light
and then in excess of a million times the speed of light

which is kinda sad.

thanks

PP

[jake-the-peg]

Depends on whether you want the original French

The English translation Hawking and Ellis (1973: 365-368)

Is referenced here
http://eprints.jcu.ed...le_Concept_Final_.pdf

Not quite sure his prediction of dark matter quite stands up in the same way. At that time it was known that you see a body by it's reflected light and it would be fairly obvious that planetary bodies would exist unilluminated by stars.

This isn't quite the same as our concept of dark matter which is almost certainly a different type of matter or an unexected interaction of known matter

[mibn2cweus]

http://books.google.c...20see%20it%22&f=false

[mibn2cweus]

I believe the reference pertains to a mass/radius where escape velocity exceeds c, if that helps with locating the quote.

http://books.google.c...20see%20it%22&f=false

[Peter Pedant]

Thanks Jake - I was using that ref as source
Harte's translation 1830 is on the internet
and I think there is nothing on both pp 305s
There is no part deux - only vol 1 and vol 2 and then the volumesa re subdivided into livres and chapitres.

[Peter Pedant]

thanks MIBN Ihave tried to search under
invisible, density, opaque, light
the difficulty with the older books is that OCR is not proof corrected so if the quote has a word like' l#ght' in it then it is lost to the world

French OCR is even worse, in one version 'invisible' scores no hits neither does densite.

[Peter Pedant]

what laplace said was:
[ Il écrivait dans son livre Exposition du Système du Monde :]

« Un astre lumineux, de la même densité que la Terre, et dont le diamètre serait 250 fois plus grand que le Soleil, ne permettrait, en vertu de son attraction, à aucun de ses rayons de parvenir jusqu'à nous. Il est dès lors possible que les plus grands corps lumineux de l'univers puissent, par cette cause, être invisibles. »
(French Wiki)[ Historique des trous noirs]

but I STILL can't find it - see above

thanksfor all your help lads

[jake-the-peg]

Looks like the quot might be wrong

348

http://fr.wikisource..../Livre_cinqui%C3%A8me

Un astre lumineux de même densité que la terre, et dont le diamètre seroit deux cent cinquante fois plus grand que celui du soleil, ne laisseroit en vertu de son attraction, parvenir aucun de ses rayons jusqu’à nous ; il est donc possible que les plus grands corps lumineux de l'univers, soient par cela même, invisibles. Une étoile qui, sans être de cette grandeur, surpasseroit considérablement le sole

[Peter Pedant]

Jake mwah mwah
and thanks for the ref
for those who dont want a weeks search

Exposition du systeme etc...
livre 5
considérations sur le systême du monde, et sur les progrès futurs de l’astronomie.
nearish the end of the chapter
chapitre 6

[Peter Pedant]

and finally......
it is at page 348 - viewers will see 348 comes into Jakes contribution - of the second edition.
and it is out of the thrid edition 1808 and therafter

(and they say isnt in the first edition but I dont have the strength to search)

and can be seen here
http://commons.wikime...d,_1798.djvu&page=349

but you will have to toggle up to 348, as the numbering seems to have a mind of their own

Many many thank
and esp to Jake

[mibn2cweus]

Of possible interest -

A paper by John Michell which appeared in 'Philosophical Transactions of the Royal Society of London' proposed the idea of 'black holes' several years (1783) before Marquis de Laplace's 'Exposition_du_système_du_monde'.

http://www.amnh.org/e...osmic/cs_michell.html

http://sqentropy.dynd...ry%20of%20time/e.html

[Peter Pedant]

This is discussed at length in the eprints.jcu .... site in Answer no 1.

AS you will all know by now the black hole ref is in editions 1 and 2 of Laplace 1794 and 1799 or thereabouts, and is dropped in the third edn of 1808 - whichI spent a lot of time reading - and Laplace does quote Michell's paper/book of 1783 but not in relation to escape velocities. same place - Livre 5 Chapitre 6 Future of astronomy
As a kinda ghost
and kinda odd as Laplace apparently was not above quoting someone else and passing it off as his own

altho Ch+ist if you look at his list of contributions he had almost no need to.

thanks everyone for their contributions