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Experts Doubt the Sun Is Burning Coal (1863)

scientificamerican.com

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Re: Experts Doubt the Sun Is Burning Coal (1863)

#141

Post by archgoon »

jaggederest wrote: post #118
archgoon wrote: post #18

Earlier quoted context omitted.

Einstein did not determine that the sun was nuclear powered. That was Hans Bethe in 1939 (based on data produced by Bengt Strömgren).

Right, I wasn't saying he did. I was trying to say that, without a theoretical framework to hang that kind of energy generation on, there was no capacity to understand what was going on. E=MC^2 is precisely that kind of theoretical framework. Pretty amazing, to me. Being able to say "It's this far away, this hot, and this large, but why?"

I don't think thats true though. In 1903, Radioactivity had already been proposed as an explanation for the Sun's heat (2 years prior to Annus Mirabilis). The connection between E=mc^2 and nuclear reactions doesn't become clear until you start losing mass (proton + neutron) in the reactions, which doesn't happen for the reactions involved in the Sun (Carbon Nitrogen Oxygen Cycle). The connection was recognized by Lise Meitner and Otto Hahn when they discovered fission, where a mass loss does occur. However, they didn't publish their discovery until January 1939; and Hans Bethe had already been working on the Carbon Nitrogen Oxygen Cycle, and didn't need fission to account for the Sun's processes (neutron + proton mass is conserved in the relevant reactions). He was just working off of observed empirical data to make his conclusions.

Re: Experts Doubt the Sun Is Burning Coal (1863)

#142

Post by philwelch »

whymauri wrote: post #55
zamadatix wrote: post #44

Earlier quoted context omitted.

I think you'd be surprised about how many really do believe the Earth is nearly that young https://news.gallup.com/poll/261680/americans-believe-creati... "People you know" is a very unreliable way to get an idea about various populations. Regardless I think the comment was about applying current "solutions" to prior times and seeing if agrees with what we'd call a good solution in retrospective, not what people beli…

My older brother has founded two separate isotope dating companies, one for C-14 dating and the other for rare isotopes. At this point, he has about 15 years of experience in the field and a decent clientele. He believes the Earth is 6000 years old, though. He rationalizes the science he works on as (the biblical) God testing his faith. My father, who works at his C-14 company, also believes this. I will never unders…

Honestly, if God created the universe 6,000 years ago and made everything seem as if it were older—I mean, that’s just a fundamentally unfalsifiable metaphysical hypothesis. For all we know, God did that last week or maybe 5 seconds ago. There’s nothing stopping that hypothesis from being true, it just makes, by definition, no measurable or practical difference and is hence irrelevant to scientific inquiry.

Re: Experts Doubt the Sun Is Burning Coal (1863)

#143

Post by im3w1l »

jaggederest wrote: post #121
adrianN wrote: post #112

Earlier quoted context omitted.

I don't understand how convection can increase the time to cool down. It seems to me that the higher temperatures closer to the surface facilitated by convection would lead to faster cooling.

Faster cooling, but smoother gradients. It means that if you go down a hundred miles, it will be warmer, but the entire center of the earth will be closer to the same temperature. If you assume a solid, you assume a certain constant thermal conductivity, as Kelvin did, even though with a liquid, that's not true. Basically, he assumed that the heat was diffusing slowly, and that it couldn't go above a certain temperat…

> If you assume a solid, you assume a certain constant thermal conductivity, as Kelvin did, even though with a liquid, that's not true

I think the liquid is a red herring here. The important thing is a that there are two layers with different properties. Would work just as well with an inner highly conductive solid.

Re: Experts Doubt the Sun Is Burning Coal (1863)

#144

Post by haunter »

QuesnayJr wrote: post #130
jolmg wrote: post #5

That passage really brings into perspective how old Scientific American is, or maybe how little ago it must've been that the composition of the sun was discovered. This was during the American Civil War.

It's shocking how in a century (say from 1850 to 1950) we went from basically knowing nothing to basically knowing everything.

>basically knowing everything

How bold! I'm pretty sure someone make a comment like yours too in ~2150 reading articles from today.

Re: Experts Doubt the Sun Is Burning Coal (1863)

#145

Post by dividedbyzero »

kd5bjo wrote: post #140
Ovah wrote: post #136

Earlier quoted context omitted.

In old Swedish (~19th century) nouns were divided into three grammatical genus: femininum, masculinum and neutrum. Dead objects could be referred to as either he or she: - earth, sun and time are feminine words and can to this day still be referred to as 'she' - heaven, road and stone were referred to as 'he', although this has disappeared from modern Swedish.

Icelandic retains the full 3-gender system to this day, and it’s generally incorrect to refer to gendered inanimate objects as “it”, rather than “he” or “she”.

Same with German, which has a neutrum genus but sometimes even uses it for people (the child, das Kind, the girl, das Mädchen, the victim, das Opfer, ...) The number of inanimate objects that are not gendered must be pretty small. The sun is female (die Sonne), a street is female (die Straße), cars and houses are neutrum (das Haus, das Auto)

Re: Experts Doubt the Sun Is Burning Coal (1863)

#146

Post by thombat »

bArray wrote: post #109

I hope they are able to figure this out, I would be interested to know how long the sun could burn on oil or kerosene. /s Legitimately though, assuming the sun is fake, how would one build an artificial sun? What could reasonably power it and give the impression to a planet within that it is real? Perhaps the problem could be even tougher if you're also trying to replicate the mass. The plot could be some advanced ci…

Possible problem with pointing lights at planets is that eventually they'll notice the moving beams from the faint zodiacal light. Of course they won't immediately conclude "the sun is a giant planetarium projector" but it will likely spur greater curiosity in observing the sun from different viewpoints.

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

Re: Experts Doubt the Sun Is Burning Coal (1863)

#147

Post by aetherspawn »

ufo wrote: post #50

This slots into the wider story about how science found out about the age of the earth, which is fascinating! In the 1860s Lord Kelvin presented[1] one of the first physical arguments in favor of the earth being millions of years old. His argument was that we could predict the age of the earth by measuring the temperature gradient at the surface of the planet (which is related to the amount of heat that is being radi…

I really hope this isn’t how they estimated the age of the earth. It’s so.. uncertain.

Like crash testing a car by using a representative model where the only commonality is the external panel dimensions and total net mass.

Re: Experts Doubt the Sun Is Burning Coal (1863)

#148

Post by acqq »

asveikau wrote: post #71
robotbikes wrote: post #35

In fact when Cecilia Payne proposed that the Sun and other stars were composed of Hydrogen and Helium in her Doctoral thesis in 1925 the conclusion was rejected by her advisor because of the conventional wisdom of the time that the earth and the sun were composed of the same elements. https://en.m.wikipedia.org/wiki/Cecilia_Payne-Gaposchkin

I thought helium was named for the sun (Helios), by spectral analysis of sunlight. In hindsight it's weird that they can know that in the 19th century (per Wikipedia of Helium) and the next conclusion has to wait until 1925, with controversy.

> In hindsight it's weird

Not, if you know that there was simply not even a concept of nuclear fusion in 19th century, and that the year of discovery of electron is 1897, and of the existence of atomic nucleus 1909.

Tangentially, but also interesting and illuminating how non-trivial all that was at that times, neutron was discovered as late as 1932 -- the same year that Hitler became chancellor of Germany. It is that recent, and it was that hard.

Re: Experts Doubt the Sun Is Burning Coal (1863)

#149

Post by guerrilla »

riffraff wrote: post #139
ardy42 wrote: post #124

Earlier quoted context omitted.

> The Sun is referred to as 'he' I wonder if they picked pronouns for the planets in accordance with the associated gods of Greco-Roman mythology? IIRC, the Greco-Roman sun gods were all male (e.g. https://en.wikipedia.org/wiki/Helios ). If I'm correct they'd use male pronouns for the sun, Mars, and Jupiter; and female pronouns for Earth, the Moon (Luna), and Venus.

Latin has grammatical genres, "Sol, Solis" is masculine and "Luna, Lunae" is female. It seems more likely to me that people just kept using the latin genres since old scientific literature was in latin.

Germanic languages, of which English was one, have this too and "sun" is Germanic in etymology. Most PIE-derived languages had this at one point but some, including English, lost it.
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