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A 9-line summary of textbook physics

motionmountain.net

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Re: A 9-line summary of textbook physics

#51

Post by archhn »

Tarq0n wrote: post #34
archhn wrote: post #28

Earlier quoted context omitted.

I like it. The author is being real. This is what he sincerely thinks. You don't have to agree with everything an author says. I for one appreciate the candor. It's also a proven fact that many smartphone applications are effectively dispensers of dopamine at regular intervals. People check their social media like smokers take a smoke break. The author is right...albeit a bit terse and dramatic.

Sharing one's thoughts candidly is worth less than good epistemology.

There's always some truth behind genuine expression, even it happens to be riddled with lies.

Re: A 9-line summary of textbook physics

#52

Post by la64710 »

PrettyPebble wrote: post #47
la64710 wrote: post #35

Why do the first chapters of all physics textbook ONLY talk about Greek philosophers and scientists and NEVER talk about contribution to Science from eastern civilization like India and China ? These civilizations have a very rich heritage and astounding contribution to many underlying scientific philosophies. Yet generation after generation of writers ignore them and it is sad to see that being true even today. It i…

The Indian number system is treated in detail. Indian mathematicians are mentioned and cited.

Good to know that , I did not go past the first few pages. Now some interesting contribution from India that I never heard of before https://www.manchester.ac.uk/discover/news/indians-predated-...

https://www.britannica.com/biography/Aryabhata-I

But I doubt that many conventional physics textbook will not even mention these and others. The writers are not to blame , but no doubt the ignorance is an unfortunate reality.

Re: A 9-line summary of textbook physics

#53

Post by not_kurt_godel »

criticaltinker wrote: post #15
PrettyPebble wrote: post #2

Fun fact: all physics experiments ever made can be described by 9 lines, without any deviation between theory and observations. The 9 lines are sufficient to describe quantum physics and gravity. It seems that the 9 lines even contain all (update: natural) sciences, not only physics. Finding an exception to the 9 lines will make you famous. So will the discovery of a 10th line. Thousands of researchers work towards t…

This is satire right? You might be getting downvotes because it’s not clear if you’re serious, and those claims seem quite ridiculous at face value.

It's essentially paraphrased from the OP. Why OP is getting upvoted, I do not know.

Re: A 9-line summary of textbook physics

#54

Post by gpvos »

> This pdf file is licensed under the Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Germany Licence, whose full text can be found on the website creativecommons.org/licenses/by-nc-nd/3.0/de, with the additional restriction that reproduction, distribution and use, in whole or in part, in any product or service, be it commercial or not, is not allowed without the written consent of the copyright owner. The pdf file was and remains free for everybody to read, store and print for personal use, and to distribute electronically, but only in unmodified form and only at no charge.

Doesn't that "additional restriction" negate the CC-BY-NC-ND license? What does it even mean?

Re: A 9-line summary of textbook physics

#55

Post by gus_massa »

> Lines 1, 2 and 3, together, uniquely determine special and general relativity, cosmology, the Hilbert Lagrangian and Einstein's field equations, as told here.

This is a huge exaggeration.

For example 1 says "W=∫L" but L is never defined. The definition of L hides a lot of details, in particular that each point of the universe is equivalent, so there is translation invariance that using the Noether's theorem implies the conservation of momentum.

There are many definitions of L, for example if you are analyzing bead that locked to a circular wire, it's usual to define L with a coordinate that follows the shape of the wire. There are also definitions of L in spherical coordinates, where each coordinate is different. Anyone with a Major in Physic has nightmares about the posibilites to define L.

For example in 2 "v ≤ c" can be true in a stupid universe where the force is bounded and there is enough friction everywhere. Imagine a universe that is full of "water" or "aether" or other magical thing with magical friction. And for some reason the force is bounded, for example like the post says in 3 "F ≤ c4/4G"

Also, I can't imagine how it is possible to rediscover all thermodynamics from "S ≥ k" in item 5.

Re: A 9-line summary of textbook physics

#57

Post by zaphar »

tvanantwerp wrote: post #36
Reventlov wrote: post #6

I opened a volume of the books linked in the page, and found this: « Learning allows us to discover what kind of person we can be. Learning widens knowledge, improves intelligence and provides a sense of achievement. Therefore, learning from a book, especially one about nature, should be efficient and enjoyable. Avoid bad learning methods like the plague! Do not use a marker, a pen or a pencil to highlight or underli…

I can't say what the author's intent was, but I see two ways to parse this: one I disagree with, one I agree with. The disagreeable interpretation is that the only way to learn is from a pristine book. This is so obviously stupid that I see no reason to discuss it further. The other interpretation, which I think is more useful but unclear from the text, is that _passive activities are subpar learning activities_. Fro…

highlighting and underlining don't per-se cause you to learn. However they do have two useful properties.

1. The act of looking for and underlining or highlighting text helps you to focus on identifying core ideas or concepts in the text.

2. Underlined and highlighted text are useful as hints when reviewing a text and reviewing a text is a critical part of learning.

These properties are so helpful that many texts actively help you to absorb their content by bolding, underlining, or otherwise calling attention to core concepts and ideas for you.

Re: A 9-line summary of textbook physics

#58

Post by PrettyPebble »

gus_massa wrote: post #55

> Lines 1, 2 and 3, together, uniquely determine special and general relativity, cosmology, the Hilbert Lagrangian and Einstein's field equations, as told here. This is a huge exaggeration. For example 1 says "W=∫L" but L is never defined. The definition of L hides a lot of details, in particular that each point of the universe is equivalent, so there is translation invariance that using the Noether's theorem implies…

For deriving special and general relativity, see https://www.motionmountain.net/maximumforce.html The page also cites the papers proving the statement.

Re: A 9-line summary of textbook physics

#59

Post by unicas »

323 wrote: post #41

I've read a few times that you can derive the Maxwell equations from knowing that U(1) exists, as this article implies, that every point in space has (among other things) the symmetry of a circle. But I've never seen this derivation. I assume it's either trivial or too complicated. Anyone has a link or thoughts on this?

There are plenty of so called "derivations of Maxwell equations", however, I would not claim that they were based on U(1) necessarily. IMO ME are just the integrability conditions for any conserved quantity (continuity equation): take a generic three-form in R^4, then dJ=0 => J=dF. F has six components corresponding to two vectofields in R^3 which depend on the fourth coordinate and satisfy the div and curl relations as in ME ;)
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