flowering_sun_star t1_jao9klh wrote

Heh, for my DPhil I basically relied entirely on Arxiv. There were very few occasions where I'd look at the journal's version of a paper.

It's a little surreal really - all the institutions pay great sums for access to various physics journals, and none of the researches actually have to use it because the web interface for arxiv.org is more convenient!


flowering_sun_star t1_j1e4k4m wrote

There's a rather good six-part series of blog posts that Bret Devereaux did about how iron and steel manufacture worked in the pre-modern world that can be found here: https://acoup.blog/2020/09/18/collections-iron-how-did-they-make-it-part-i-mining/

As part of it he notes that the investment the romans made into their legions was really quite incredible. Towards the end of part two he notes that the armaments of a legion of 5000 might amount to nearly 50 tons of iron, representing eighty thousand days of labour to make the charcoal alone. They completely deforested vast swathes of land to fuel their empire.

If we take a gladius to be 700g of iron, 3.5 of those tons would be in the swords. But a spear head isn't actually that much lighter. I've seen estimates of medieval spearheads at about half that. Let's say it's 300g, and you can save 2 tons of iron by going to spears. That's just 2 tons out of about fifty! Not really a huge saving in the grand scheme of things.


flowering_sun_star t1_iz6dvvz wrote

Yeah, that struck me as a pile of bollocks. In fact if you want something to hang flat in a particular orientation then two holes like that possibly the best way to go. You can have a single thread enter from the back, cross to the other, and leave to the back again. It can't easily rotate without twisting together the two end of the thread, and the separation between them makes that harder.

Maybe the holes were for something else, but this logic sounds like they wanted to find an excuse to reject the simpler explanation.


flowering_sun_star t1_ixnfu0h wrote


Things falling towards a black hole have an extraordinary amount of energy. Something free falling towards one would pick up a vast amount of speed before crossing the event horizon. Which means if it smacks into anything that event is going to be energetic. If something actually is orbiting, it needs to change speed a lot to drop below the ISCO (innermost stable circular orbit). And that is also an energetic process.

So while nothing can escape the black hole itself, the system around it can have a lot of energy to spare that make accreting black holes some of the brightest objects in the universe. As well as photons they can also produce impressive jets of matter. Nobody has ever doubted that there is plenty energy to spare to make the jets, but the mechanism has been a bit of a mystery.


flowering_sun_star t1_iur8t0i wrote

Historian says yes!

I would say maybe, but not much is needed. I'm coming at this from the perspective of someone with a degree in physics and PhD in astrophysics, with an interest in various areas of history that rarely have anything to do with the sciences. (Though I am interested in how the early USSR approached the field of statistics, so if anyone has any recommendations there I'd be grateful)

As part of my education we quite frequently did learn about the history of the concepts we were studying. It is useful to learn about older ideas of how things were, why they might have been reasonable to believe at the time, and how they were proven wrong. And also something of the history of the scientists who made various discoveries. I remember one lecturer making sure to point out that the dubious history of the man the Lindemann lecture theatre we were in was named for.

So yes, a history of where the field has come from is useful, and is already present as part of an education in the sciences. But when it comes to actually doing scientific research, no it really isn't needed. When you're trying to figure out a sensible geometry for your simulation or analyze a time-series, the history of the techniques you're using really isn't relevant. The history of physical simulation is likely a fascinating topic for someone to study, but has no bearing on how you go about actually doing it.

And all this talk about the usefulness of history to the sciences has been about the use of the outputs of the academic field. It is useful to know the facts of where things came from, but history as a field is so much more than that. But the practice of doing history isn't really relevant at all to the sciences (except in so far as it is relevant to everything).

The converse really isn't true. The practice of doing history often requires, in part, doing science. Be it dating, statistical analysis of economic data, climate records, or many other things. After all, without that grounding in reality you're just telling stories.


flowering_sun_star t1_iur34ym wrote

> where one of the proposed solutions for the behavior of quanta is the rejection of free will

The attempts to involve quantum physics with free will are widely regarded as a great steaming pile, and are rarely proposed by anyone with an inkling as to what quantum physics actually is. It is far too often treated as a form of magic get-out-of-causality-free card, and peddled by woo-mongers precisely because so few people have any understanding of the matter.

So yeah, you probably got banned for promoting unscientific nonsense.


flowering_sun_star t1_itu0zmd wrote

Q is a consonant, while O is a vowel that can have many different pronunciations. They perform very different roles.

It's hard for an English speaker to understand where you're coming from because in English a vowel can have many different pronunciations, and we are comfortable with that. We also understand that other languages use diacritics to provide hints on pronunciation.

It seems really weird to us to insist that a character, and that character with diacritics, are fundamentally different things. Especially when the base character in an English text could reasonably be used to represent both those sounds. And remember that this is all in the context of an English language text!

I'm perhaps just surprised at how up-tight all the swedes are over a simple choice in transliteration. Maybe it is you who need the reminder that not all languages share an alphabet?