Experts Doubt the Sun Is Burning Coal (1863)

Actually, the headline is not bollocks, but 100% correct. It is NOT a giant lump of burning coal!

It wasn't really a controversy or dogmatic issue to average Christians until the early 20th century. Trying to argue with a Young Earth Creationist on scientific grounds is super pointless - literally everything can be either dismissed because you weren't present, or reinterpreted to fit the viewpoint. I would know because that used to be me.

It's also highly unlikely that you'll successfully argue with them from a theological/hermeneutical perspective either. If you'll forgive me entering into a major time controversy here: a young earth creationist, and many evangelicals, place the original Biblical text as penned by the human author at a nearly deified level. Unless the text is blatantly poetic, even in translation, or explicitly labelled a parable the text is assumed to be literal.

The human author of scripture is basically assumed to be, more-or-less, possessed by the deity lending only their authorial voice to the literally word-for-word transcript given to them by God. (For support they quote scripture, of course, "All Scripture is God-breathed and useful for teaching, rebuking, correcting, and training in righteousness" (II Timothy 3:16). Believing that, the stakes become incredibly high for a biblical literalist, many/most of whom are also YEC. If any scripture is found to be "false" by modern standards, it basically invalidates the whole thing.

I say this having believed this version of Biblical inspiration and knowing I'd have been given permission to teach it in church once upon a time.

The tricky bit is that modern standards aren't an appropriate measure to hold an ancient document with different goals, but that's literally a books worth of argument and background to dive into.

No, it isn't. It's correct in the basic claim of the title. Scientists in 1863 who believed that no known source of energy was capable of powering the Sun were right. The Sun is not powered by any source of energy that was known in 1863.

> I would prefer if there was some more working shown to back up the article

Scientific American wasn't the place to show the details then any more than it is today. But the calculations are simple to do, and plenty of physicists had done them at the time of the article.

A summary of the calculations:

Chemical reactions, which is what burning coal is an example of, produce an energy per unit mass of fuel on the order of 10^8 Joules per kilogram. (That's actually on the high end, but it's fine for a rough calculation.) The Sun's mass is about 2 x 10^30 kilograms today; if we assume that half of that is burned as fuel, we get a total energy of 10^38 Joules. The Sun's power output is about 4 x 10^26 Watts, so 10^38 Joules will supply the Sun's power output for about 2 x 10^11 seconds, which is pretty close to 5,000 years (a year is about 3 x 10^7 seconds).

Meteorite impacts essentially convert gravitational potential energy to heat, so the energy per unit mass available is the change in gravitational potential energy from the average distance of a meteorite from the Sun when it starts falling in, to the radius of the Sun. That difference is GM/R - GM/r, where R is the Sun's radius and r is the distance from which the meteorite starts falling in. If we take the maximum possible change, that will be for r -> infinity, in which case our potential energy gain is just GM/R. G is about 7 x 10^-11, M we have from above, and R is about 7 x 10^8 meters. This works out to 2 x 10^11 Joules per kilogram. At that rate, to supply the Sun's power output for 100 million years (about 3 x 10^15 seconds) would take about 6 x 10^30 kilograms, or 3 times the Sun's mass.

That tells me that the article greatly overestimated the potential mass of meteorites available, since the Sun is something like 99 percent of the mass of the solar system, and even counting in the Oort cloud doesn't change that number appreciably. An optimistic upper limit based on current knowledge would be something like 0.1 percent of the Sun's mass (since most of the 1 percent of mass that is not the Sun is the planets, not meteorites), and even that is probably much too large. But taking that value gives an time of 1e12 seconds, or about 30,000 years.

(Note that later in the 1800s, someone--I think it was Lord Kelvin--calculated how long the Sun could be kept shining by gravitational contraction--i.e, by just contracting its own mass to a smaller radius and converting gravitational potential energy into radiation. He came up with a figure of something like 10 million years, which is about what you get if you take the potential energy change formula I gave above and plug in an r--the distance from which "falling in" starts--of something like twice the Sun's radius, and then multiply by the entire mass of the Sun. That's basically what Kelvin's calculation did.)