Cecilia Payne-Gaposchkin discovered that stars are mostly made of hydrogen
aps.org
aps.org
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).
- 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!
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.
What speculative theorizing are we doing in the 2020s that we might similarly look back upon?
Maybe Dark Matter and Dark Energy?
Inflationary cosmology.
Extraterrestrial intelligence/life.
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.
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.
really, I expect at minimum an earth sized iron core in the sun, it is probably much more.
https://en.wikipedia.org/wiki/Solar_core
At the edge of the core is about 70% hydrogen 28% helium with the helium fraction increasing up to 66% right at the center.
One thing I think you're missing is how overwhelmingly the cloud that formed the solar system was hydrogen and helium.
https://en.wikipedia.org/wiki/Formation_and_evolution_of_the...
The gas cloud that formed the solar system is expected to have been 98% hydrogen and helium, 2% everything else. We don't see these ratios on rocky planets like earth because the gravity here isn't strong enough to hold the hydrogen and helium, so mostly it escaped and we have a wildly non-representative sample of elements left.
Nevertheless, the standard model of the Sun supposes that, because of the very high temperature, the interior of the Sun remains mixed well enough so that the heavy elements like iron cannot segregate to form a distinct core, but only, as you have mentioned for helium, the concentration of heavy elements is somewhat higher in the center than at the surface.
However the standard model of the Sun is not very certain, because the behavior of matter at extremely high pressures and temperatures is not known well enough.
If there was an iron core, it would vaporize in the center of the sun because it's extremely hot there.
A few years ago, someone measured the energy of the neutrinos produced by the fusion in the center of the Sun [1].
[1] perhaps there are some details in https://en.wikipedia.org/wiki/Solar_neutrino
There is an exothermic fusion chain of elements that are burned in stars, the last stage of which is silicon, that ends with iron.
https://en.m.wikipedia.org/wiki/Silicon-burning_process
At iron, no further exothermic fusion is possible, so the core is no longer able to resist the pressure of collapse.
The iron atomic nuclei themselves break down, the protons combine with electrons to form neutrons where they are able, and if the total mass is below the Tolman–Oppenheimer–Volkoff, then neutron degeneracy pressure is able to stop the collapse, otherwise a black hole forms.
https://en.m.wikipedia.org/wiki/Tolman%E2%80%93Oppenheimer%E...
A star needs to be 8 solar masses for this to happen. Our sun ends at carbon.
Wikipedia says the TOV limit is ~3 solar masses?
They were consumed as fuel to maintain the outward pressure of the core.
The Earth does not have its iron core because individual iron atoms, being heavier, individually diffused downward into the core. Some heavy elements, like uranium, are actually highly concentrated in the continental crust, because chemically they partition into lower density phases.
In the Sun, with everything inside vaporized, there is and was no partitioning into distinct chemical phases of differing density. There is a chemical difference in the Sun's core, though: it is now enriched in helium and somewhat depleted in hydrogen because of nuclear fusion over billions of years. This process is gradually making the core denser and hotter, increasing the overall rate of fusion. The Sun is now 30% brighter than it was when it settled onto the main sequence.
Separation by mass of ions does occur in the surface layers of white dwarf stars; the conditions there are such that separation by diffusion can be significant. Some such stars have been seen with "metals" (elements heavier than helium) in their crusts; this has been interpreted as evidence of recent accretion of material from disrupted asteroids or planets.
Even if the sun were 100% iron, at its current mass it would not collapse into a black hole.
I interpreted the original comment as if the Sun, with its current mass, had an iron core. A star with the mass of the Sun cannot have produced iron, so it would have had to have formed with an iron core. This is certainly ruled out by other data, of course.
“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.
Did she randomly decide which ones she would pray for? Perhaps she was more likely to pray when she knew she was less prepared.
Seems odd that she would test the efficacy of someone else intervening without first confirming if they'll participate.
If you need elaboration: For God to impose a punishment or give a reward the person must have free will. If you took that away, then humans would become like animals (or angels if you prefer) who don't have free will. When Genesis 1:27 says "in his own image", that's what it means: With free will.
This also means there's essentially a religious mandate to study science. Science is God's alternative explanation for how the world works, so studying it is essentially studying God.
This is also why Young Earth Creationists don't understand their own religion. They are attempting to find proof of God, which is something that their own religion claims isn't possible.
Everything you just said is a hypothetical. So is the existence of the Rabbit's hole in Alice in Wonderland.
I guess I say this because I wish someone had told younger me: "You just don't need to believe any of this stuff. You don't need an argument for doing so, really, just like you never needed an argument not to be Jain or Hindu. You can just stop believing it."
In any case, I don't buy this particular argument anyway. In fact, one can just as easily construct the exact opposite: a person's will isn't free unless they have perfect information. God had to reveal himself directly in the inspired works of the bible because if people didn't know that he existed it would be unjust to judge them for deciding or failing to decide to follow him.
Angels, in fact, according to some adherents of your religion, knew everything about the reality of God and some still chose to disobey and were punished. And we don't exactly have to comb the new Testament to find examples of Jesus working miracles/granting prayers right in front of everyone, which also contradicts your idea.
Christian apologetics is a big pile of bad arguments.
Who? What are these rules of which you speak? Which respectable peer-reviewed publication may I find the rules in?
If god does exist, then this is not a double blind experiment.
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.
- 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".
Anyways, that test does not pass the smell test for me.
Don't blink.
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.
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