Cecilia Payne-Gaposchkin discovered that stars are mostly made of hydrogen

https://www.aps.org/people/cecilia-payne-gaposchkin

by _Microft • 2 years ago

128 53 2 years ago

aps.org

_Microft• 2 years ago

There is also a substantial article on Wikipedia about her if you want to know more:

https://en.wikipedia.org/wiki/Cecilia_Payne-Gaposchkin

Jun8• 2 years ago

I loved this bit:

“In her autobiography, Payne tells that while in school she created an experiment on the efficacy of prayer by dividing her exams in two groups, praying for success only on one, the other one being a control group. She achieved the higher marks in the latter group.”

Assuming the result was statistically significant, what would be the theory she used to explain the result? Evidently god does not exist (it says she became an agnostic in later life). But in that case wouldn’t the two groups have similar outcomes? Probably the thought of an outside force helping vs I’m on my own thinking was the cause. Or God had other plans for Cecilia.

elromulous• 2 years ago

I know this is somewhat tongue in cheek, but I'm going to answer as if it's serious:

Did she randomly decide which ones she would pray for? Perhaps she was more likely to pray when she knew she was less prepared.

esafak• 2 years ago

https://en.wikipedia.org/wiki/Efficacy_of_prayer

WorkerBee28474• 2 years ago

One simple theory is that God does not like to be tested. That's also plainly said in the Bible.

Seems odd that she would test the efficacy of someone else intervening without first confirming if they'll participate.

robertlagrant• 2 years ago

what would be the theory she used to explain the result

If god does exist, then this is not a double blind experiment.

SkiFire13• 2 years ago

I guess one group had more time to study

gus_massa4• 2 years ago

Assuming the result was statistically significant, what would be the theory she used to explain the result?

Assuming the result was statistically significant:

It's very difficult to isolate all the variables. Perhaps the last 15 minutes before the exam she prayed instead of studding. Perhaps she studied less because she secretly hoped the experiment to go this way.

Double blind randomized controlled trial or it didn't happen.

Also, there is reporting bias, for example if she got the oposite result, perhaps she would have not mentioned it so often.

And perhaps she has some methodological error we can guess without a detailed report. Perhaps she had some weird exception list in the exams she counted.

Preregistered double blind randomized controlled trial published is a serious peer review journal or it didn't happen.

And we now have to discuss what serious means that is another can of worms. And ignore the webpages that claims that the comment section is peer review.

cryptonector3• 2 years ago

The result of that experiment could mean a variety of things, such as:

  - sample size too small (too few tests,
    too few test subjects)
  
  - poor test setup
  
  - praying for success made her complacent,
    thus not leading to success as often as
    when not praying for success
  
  - praying for oneself is not rewarded but
    punished
  
  - God does not permit scientific experiments
    to prove God's existence, even indirectly
    via measuring the effectiveness of prayer
  
  - other reasons such as your "[o]r God had
    other plans for Cecilia".

A theologist can probably come up with more reasons.

Anyways, that test does not pass the smell test for me.

timthorn• 2 years ago

A new play based on her life has just opened in London: https://www.hampsteadtheatre.com/whats-on/2024/the-lightest-...

aebtebeten• 2 years ago

compare https://xkcd.com/2340/

seanhunter2• 2 years ago

It's really funny because my dad (a chemical engineer) had a hobby interest in cosmology. He used to go nuts about people calling produce "organic" and would love to point out that all produce is organic in the sense that it all is made of carbon-based molecules. Yet on the other had no problem with the fact that cosmologists call just about everything in the whole periodic table a metal.

somat2• 2 years ago

I went down an interesting rabbit hole recently, I was trying to figure how big the iron core of the sun was and the answers were surprisingly all over the place.

There is the no iron core/fractional percentage gang which bases their theory on the observed sun, but this conflicts with the common cloud theory of solar system origin, which is basically there was enough iron in the proto cloud to provide iron cores for most of the inner planets and you are telling that you think that most of this iron did not end up in the middle of the sun.

then at the far end of the spectrum is the crackpot "the solar system is a second generation(minimum) system, some star must have exploded to form the metals we see, the core of the sun is probably the stellar remnant of the first generation system and is mostly iron"

But really I wonder, all our observations of the sun are of the upper atmosphere, and more importantly the light emitted by the upper atmosphere, if earth was observed the same way you would conclude it was mainly made of nitrogen.

chasil5• 2 years ago

Our sun does not have an iron core. If it did, it would immediately collapse into a black hole.

When the sun burns all of the hydrogen in the core, it will then burn helium. The burning will end at carbon.

https://en.m.wikipedia.org/wiki/Carbon-burning_process

Silicon burns to iron, which becomes degenerate matter that cannot resist gravitational collapse.

somat2• 2 years ago

There was a bunch of iron in the proto dust cloud that formed this solar system(i pick on iron because it is a nice infliction point past which you get no energy from fusion, but really include all of the middle stable elements here), as the dust cloud collapsed it formed an iron core in all the planets, and many asteroids. but no core in the sun, explain how that is possible.

really, I expect at minimum an earth sized iron core in the sun, it is probably much more.

pfdietz5• 2 years ago

Our sun does not have an iron core. If it did, it would immediately collapse into a black hole.

Even if the sun were 100% iron, at its current mass it would not collapse into a black hole.

https://en.wikipedia.org/wiki/Chandrasekhar_limit

DiggyJohnson• 2 years ago

Linking to Wikipedia is ridiculous here, considering we are discussing the current scientific debate and consensus. You just worded your contribution more forcibly.

phkahler• 2 years ago

I recently realized it takes light over 4 seconds to cross the diameter of the sun. It seems absurd to conclude what's inside it based on light emitted at the surface. Other methods of deduction maybe, but not that.

cryptonector3• 2 years ago

The Sun is opaque to light in its interior. The light we see -and its absorption lines- is emitted in the photosphere, far from the core.

chasil5• 2 years ago

...unless they are (massive enough to be) at the other end, the "silicon burning phase."

Don't blink.

https://en.m.wikipedia.org/wiki/Silicon-burning_process

compressedgas• 2 years ago

The page says very brief. The source cited states 18 days for a 15 solar-mass star.

chasil5• 2 years ago

Two other women who have made similar profound impacts upon astronomy are Henrietta Swan Leavit (who discovered Cephid Variable stars, which are used as "standard candles" for distance measurement), and Jocelyn Bell (who discovered the pulsar class of neutron stars).

https://en.m.wikipedia.org/wiki/Cepheid_variable

https://en.m.wikipedia.org/wiki/Pulsar

seanhunter2• 2 years ago

She has a patera (volcanic crater) on Venus named after her https://planetarynames.wr.usgs.gov/Feature/4623

renox• 2 years ago

Thanks, I didn't know about her which is a shame because her discovery is Nobel worthy..

perihelions2• 2 years ago

The theory that hydrogen fusion powers stars is actually older than the discovery that the sun is made of (mostly) hydrogen. Eddington proposed it in 1920. It wasn't necessary to assume a "mostly hydrogen" sun—his estimate was that a >5% hydrogen sun would be sufficient.

https://sci-hub.se/10.1126/science.52.1341.233

The immediate historical motivation wasn't the discovery of hydrogen in the solar atmosphere, but the discovery, on Earth, that the hydrogen atom is anomalously heavy (~1% mass excess per nucleon).

perihelions2• 2 years ago

(Eddington's is rather an astonishing paper, science aside, just for the remarkable breadth of perspective written down in one place 100 years ago. Within eight pages, he is contemplating all of:

- The perspective that all of the matter life is made of may have been forged in the "crucibles" of stars;

- The perspective that the timeline of the planet Earth should be expanded from ~20 million years, to multiple billions (and the specific implications for biological evolution);

- The perspective that hydrogen fusion could be the energy source of future civilization—or a source of weapons that end it

All of this, purely speculative theorizing, in 1920!

ZeroGravitas• 2 years ago

I think the point about the age of the earth and evolution might be backwards.

Lord Kelvin had worked out that the earth might be only 20 million years old maybe 60 years earlier based on continually losing heat.

But even at that earlier time biologists and geologists were suggesting that number wasn't high enough to explain what they were seeing in their fields. I think Darwin had suggested a lower bound of at least 300 million based on the erosion he saw locally.

echelon• 2 years ago

All of this, purely speculative theorizing, in 1920!

What speculative theorizing are we doing in the 2020s that we might similarly look back upon?

netcoyote• 2 years ago

Record levels of solar-related deaths this year spawned calls for increased research of the sun to identify potential solutions, with some groups calling for sun-related regulation to reduce the shockingly high death tolls, including those related to heatstroke and famine, as well as longer-term issues including skin-cancer. Hurricanes are also considered a major issue given their proximity to the Capitol.

Also at issue is the large amount of the chemical element hydrogen which makes up the sun, which is a significant fire hazard, though some in the scientific community downplay its risk.

The issue is expected to be especially significant in this election year.

Left-wing politicians in Congress are calling for more sun research funding to provide greater clarity on the issues facing voters, though several of their more extreme members have already introduced competing bills to the House floor with proposals to reduce solar intensity, increase shielding around at-risk neighborhoods, or mandate warning labels in key locations.

Conservatives members of Congress deny that the sun is a significant source of risk, or in the event that it is an issue, that Congress should enact legislation to address the problem. "US citizens are aware of the risks, and should be able to exercise their god-given rights to do as they please in the sun."

On the far right end of the spectrum the senator from South Florida has introduced legislation to reclassify hydrogen as helium, an inert gas that poses no burn risk, and has industrial and commercial uses that would be a boon to US industry.

The senator was quoted as saying, "We've got to prevent foreign helium from undercutting the US market, and so my bill would radically increase the supply of this critical element used in birthday balloons while protecting US jobs from unfair competition." The senator had no comment about reports of contributions to his campaign from the American Society for the Suppression of Helium, Oxygen, and Lithium in Energy imports.

Cecilia Payne-Gaposchkin discovered that stars are mostly made of hydrogen

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