> [She] proposed in her 1925 doctoral thesis that stars were composed primarily of hydrogen and helium. Her groundbreaking conclusion was initially rejected because it contradicted the scientific wisdom of the time, which held that there were no significant elemental differences between the Sun and Earth.
I'm reminded of a college lecture one day in a class I took called Physics of Stars. The professor walked up to the whiteboard and wrote:
Elemental composition of the universe:
Hydrogen and helium 99%
Oxygen ~1%
Everything else <<1%
That was well over a decade ago, and it blows my mind as much today as it did then.
In astronomy we label everything in the "Everything else" bucket as "metals." So oxygen and carbon are considered metals in astronomy. Our periodic table is quite a bit simpler.
I got interested in that after your comment, and apparently there are two main reasons for that.
1. Oxygen is being produced in stars by so-called CNO cycle [0], which is how stars heavier than our sun mostly do their fusion. More intriguing question is why there's more oxygen than carbon or nitrogen (which, as implied by the name of the process, are also created), but that's a different topic.
2. Additionally, oxygen-16 is a particularly stable isotope, as its nucleus has “doubly magic” [1] amount of constituents, so it doesn't get destroyed in other processes.
I would imagine that oxygen is at some sort of happy medium of being easy enough to create through fusion but hard enough to fuse into other things that it is unexpectedly common.
Kind of entertaining, in hindsight, to the read the reasoning of the Compton & Russell paper [0] cited in Payne-Gaposchkin's thesis [1] as the explanation of the "spurious" hydrogen abundance:
- "This would demand an absurdly great abundance of hydrogen relative to magnesium (itself an abundant element)[...] It appears necessary, therefore, that the effective value of q_2 for the two-quantum state of hydrogen is increased in some special way, by a very large factor..."
“Her groundbreaking conclusion was initially rejected because it contradicted the scientific wisdom of the time, which held that there were no significant elemental differences between the Sun and Earth.”
Why did people think the Sun was producing light, there must have been an explanation? Hard to believe that only 100 years ago we knew so little about cosmology.
They had a very plausible explanation: gravitational binding energy. It's the wrong one for the sun, but it's the correct one for non-fusing brown dwarfs.
The time period from around 1600->1900 is so fascinating, in that there are some things we had correctly figured out that are just amazing, and other things where we were so far off it seems embarrassing in retrospect. It must have been a fun time for curious people, quite a lot you could discover without huge teams and huge sums of money and equipment.
Latacora's primary infrastructure auditing tool is called payne, after Cecilia. It takes "snapshots" of infrastructure: e.g. an entire AWS resource graph, and then makes that available via fast queries. It figures out what your cloud is made of by looking at API responses (which kind of are like emission spectra I guess?) :)
I knew her son Peter[1] fairly well through the Berkeley Quaker meeting, though did not learn about her illustrious science contributions until after he died.
TIL in 1925 it was thought that the Sun had no elemental difference from the Earth, and women were barred from becoming professors at Harvard. Basically dark ages.
Not just that - also "She completed her studies, but was not awarded a degree because of her sex; Cambridge did not grant degrees to women until 1948."
I was equally shocked to read that. But in context, the 20th century was still in large parts dark ages for women regarding their rights. For instance, I just read they were only permitted to vote in parts of Switzerland from 1990!
> The first federal vote in which women were able to participate was the 31 October 1971 election of the Federal Assembly. However it was not until a 1990 decision by the Federal Supreme Court of Switzerland that women gained full voting rights in the final Swiss canton of Appenzell Innerrhoden.
It's a kind of depressingly common stage in institutions becoming coeducational: many of them allowed women to take classes for years (townies, daughters of faculty, etc.) but didn't fully integrate them into the academic experience; they generally didn't formally matriculate and were often either granted no degrees or given a "lady's degree" without a graduation ceremony.
Women couldn't even be Harvard students, never mind professors! Her diploma would have said "Radcliffe College" - they didn't start putting the name Harvard alongside Radcliffe for another few decades.
Readit News
I'm reminded of a college lecture one day in a class I took called Physics of Stars. The professor walked up to the whiteboard and wrote:
Elemental composition of the universe:
That was well over a decade ago, and it blows my mind as much today as it did then.1. Oxygen is being produced in stars by so-called CNO cycle [0], which is how stars heavier than our sun mostly do their fusion. More intriguing question is why there's more oxygen than carbon or nitrogen (which, as implied by the name of the process, are also created), but that's a different topic.
2. Additionally, oxygen-16 is a particularly stable isotope, as its nucleus has “doubly magic” [1] amount of constituents, so it doesn't get destroyed in other processes.
[0]: https://en.wikipedia.org/wiki/CNO_cycle
[1]: https://en.wikipedia.org/wiki/Magic_number_(physics)
- "This would demand an absurdly great abundance of hydrogen relative to magnesium (itself an abundant element)[...] It appears necessary, therefore, that the effective value of q_2 for the two-quantum state of hydrogen is increased in some special way, by a very large factor..."
[0] https://sci-hub.se/10.1038/114086a0 ("A Possible Explanation of the Behaviour of the Hydrogen Lines in Giant Stars (1924)")
[1] https://articles.adsabs.harvard.edu//full/1925PhDT.........1...
Why did people think the Sun was producing light, there must have been an explanation? Hard to believe that only 100 years ago we knew so little about cosmology.
https://en.wikipedia.org/wiki/Kelvin%E2%80%93Helmholtz_mecha... ("Kelvin–Helmholtz mechanism")
Experts Doubt the Sun Is Burning Coal (1863) (scientificamerican.com) https://news.ycombinator.com/item?id=23074435
https://en.wikipedia.org/wiki/Sisters_of_the_Sun
[1]: https://www.berkeleyside.org/2014/10/29/in-remembrance-peter...
> The first federal vote in which women were able to participate was the 31 October 1971 election of the Federal Assembly. However it was not until a 1990 decision by the Federal Supreme Court of Switzerland that women gained full voting rights in the final Swiss canton of Appenzell Innerrhoden.
For half the money, too, probably
Is anyone surprised?
(disclaimer: these are just educated guesses, I don't actually know you)
Dead Comment