# TIL (today I learned)... \[astronomy\] **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [September 2, 2020, 2:55am UTC](https://boards.straightdope.com/t/til-today-i-learned-astronomy/919571 "2020-09-02T02:55:27Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Lucas\_Jackson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lucas_jackson/32/303_2.png) [@Lucas\_Jackson](https://boards.straightdope.com/u/Lucas_Jackson)\ **Post date:** [September 2, 2020, 2:55am UTC](https://boards.straightdope.com/t/til-today-i-learned-astronomy/919571/1 "2020-09-02T02:55:27Z")
On November 27th, 1783, John Michell first proposed the idea that there were such things as [black holes] which he called “dark stars” two hundred years before anyone else. He correctly deduced they would be created by extreme gravity. Big Al still gets all the credit. What interesting fact have you learned recently? ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [September 2, 2020, 3:22am UTC](https://boards.straightdope.com/t/til-today-i-learned-astronomy/919571/2 "2020-09-02T03:22:45Z")
[Wow!](https://en.wikipedia.org/wiki/John_Michell) > [@](#): > > Considered “one of the greatest unsung scientists of all time”,[[1]](https://en.wikipedia.org/wiki/John_Michell#cite_note-1) he was the first person known to offer the following concepts: proposed the existence of [black holes](https://en.wikipedia.org/wiki/Black_hole); suggested that earthquakes traveled in [(seismic) waves](https://en.wikipedia.org/wiki/Seismic_waves); explained how to manufacture an artificial magnet; and, recognizing that [double stars](https://en.wikipedia.org/wiki/Double_star) were a product of mutual gravitation, he was the first to apply [statistics](https://en.wikipedia.org/wiki/Statistics) to the study of the [cosmos](https://en.wikipedia.org/wiki/Cosmology). He invented an apparatus to measure the [mass of the Earth](https://en.wikipedia.org/wiki/Earth_mass). He has been called the father both of [seismology](https://en.wikipedia.org/wiki/Seismology) and of [magnetometry](https://en.wikipedia.org/wiki/Magnetometry). ---
**Author:** ![Andy\_L](https://avatars.discourse-cdn.com/v4/letter/a/c67d28/32.png) [@Andy\_L](https://boards.straightdope.com/u/Andy_L)\ **Post date:** [September 2, 2020, 3:13pm UTC](https://boards.straightdope.com/t/til-today-i-learned-astronomy/919571/3 "2020-09-02T15:13:35Z")
> [@Lucas\_Jackson](#): > > On November 27th, 1783, John Michell first proposed the idea that there were such things as [black holes] which he called “dark stars” two hundred years before anyone else. He correctly deduced they would be created by extreme gravity. > > Big Al still gets all the credit. Big Al didn’t do much with black hole theory - Schwarzschild, Eddington and Oppenheimer (and later Kerr, Newman and Hawking of course) were more important in that area (though they all worked with Einstein’s equations of course). Einstein himself didn’t believe the black holes were physically possible. ---
**Author:** ![Lucas\_Jackson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lucas_jackson/32/303_2.png) [@Lucas\_Jackson](https://boards.straightdope.com/u/Lucas_Jackson)\ **Post date:** [September 2, 2020, 6:48pm UTC](https://boards.straightdope.com/t/til-today-i-learned-astronomy/919571/4 "2020-09-02T18:48:19Z")
Interesting. Just now I googled “who first proposed black holes” and the first hit was Albert Einstein. “ **Albert Einstein** first predicted the existence of black holes in 1916, with his general theory of relativity.” I think the perception is that it was Einstein whether he actually did or not. ---
**Author:** ![GreenWyvern](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/greenwyvern/32/2834_2.png) [@GreenWyvern](https://boards.straightdope.com/u/GreenWyvern)\ **Post date:** [September 2, 2020, 7:16pm UTC](https://boards.straightdope.com/t/til-today-i-learned-astronomy/919571/5 "2020-09-02T19:16:15Z")
> [@Lucas\_Jackson](#): > > the first hit was Albert Einstein It’s correct that Einstein should get the credit. Michell based his speculation on the corpuscular theory of light, i.e. that light consists of particles that are attracted by gravity. He thought that when the escape velocity was greater than the speed of light, particles of light would fall back to the star. This is incorrect. In the 1860s Maxwell showed that light is an electromagnetic wave. Later the wave-particle duality was discovered. There’s a superficial similarity between the ideas of Michell and Einstein, but in fact they are very different. General Relativity predicts a bending of spacetime in the vicinity of mass, which is the reason the trajectories of photons are bent, even though photons are massless. ---
**Author:** ![Andy\_L](https://avatars.discourse-cdn.com/v4/letter/a/c67d28/32.png) [@Andy\_L](https://boards.straightdope.com/u/Andy_L)\ **Post date:** [September 3, 2020, 12:19pm UTC](https://boards.straightdope.com/t/til-today-i-learned-astronomy/919571/6 "2020-09-03T12:19:53Z")
> [@Lucas\_Jackson](#): > > Interesting. Just now I googled “who first proposed black holes” and the first hit was Albert Einstein. > > “ **Albert Einstein** first predicted the existence of black holes in 1916, with his general theory of relativity.” > > I think the perception is that it was Einstein whether he actually did or not. Huh. I tried the same Google and got the same result. But if I tried “Who invented black holes?” I get Karl S.