This page is written to make you, the reader, think, disagree, wonder, check and enjoy.
 

This 9-line summary of textbook physics agrees with 400 years of experiments. Exactly.

The 9 lines, typeset in bold, state that general relativity, the standard model of particle physics and thermodynamics describe all of nature.

The 9 lines show everything we know about natural science and everything we do not know about fundamental physics.

An extended version is here: C. Schiller, Present physics in 9 lines - and implications for its future, preprint.  
 

1. Nature dislikes squander:	dW = 0	Action W=∫L dt is minimized in every motion. Locally, L = Ekin-Epot; the lines below fix the Lagrangian L.	Vol. I: Fall, Flow and Heat.
2. Nature dislikes hurrying:	v ≤ c	Energy speed v is limited by the speed of light c. This implies special relativity and its possible Lagrangians.	Vol. II: Chapters on Special Relativity.
3. Nature dislikes excessive force:	F ≤ c4/4G	Force F is limited by c and the gravitational constant G. This implies general relativity and its Lagrangian.	Vol. II: Chapters on General Relativity and Cosmology.
4. Nature dislikes sloth:	W ≥ ℏ	Action W is never smaller than the quantum of action. This implies quantum theory.	Vol. IV: The Quantum of Change.
5. Nature dislikes perfect order:	S ≥ k ln2	Entropy S is never smaller than O(1) times the Boltzmann constant k. This implies thermodynamics.	Vol. I        (and Vol. VI)
6. Electric charges are conserved and attract or repel:	U(1)	is the gauge symmetry of electromagnetism. It yields its Lagrangian.	Vol. III: Light, Charges and Brains.
7. Nuclei show two other types of charges and forces:	SU(3) & broken SU(2)	are the gauge symmetries of the two nuclear interactions, yielding their Lagrangians.	Vol. V: Pleasure, Technology and Stars.
8. Nature determines the elementary particles:	18 particles	– bosons, quarks and leptons – with their charges and other quantum numbers, make up everything.	Vol. V: Pleasure, Technology and Stars.
9. Nature determines the fundamental constants:	Finally, 27 numbers	– dimensions, cosmological constant, coupling constants, particle mass ratios, mixings – complete the two basic Lagrangians and determine all observations & colours.	Vol. V: Pleasure, Technology and Stars.

 
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The 9 lines contain all present knowledge about nature, including all textbook physics and all observations ever made.

The simplicity of the 9 lines and their vast domain of validity are intensely fascinating.

No known observation and no known measurement contradicts these 9 lines, not even in the last significant digit.

Find a single contradicting observation or experiment and become famous.

The 9 lines determine all equations of physics:

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

Line 5 uniquely implies thermodynamics.

Lines 1, 2, 4 and 6 to 9, together, uniquely determine quantum field theory and the Lagrangian of the standard model of particle physics, with massive neutrinos and PMNS mixing – often written with a Lagrangian taking a full page in a small font.

The 9 lines show how little math is required to describe nature with high precision.

The 9 lines given on this page improve the humorous 9 lines found here.

The 9 lines resulted from the work of millions of engineers and scientists during 400 years.

Galileo started around the year 1600; line 1 resulted after over 150 years. Line 5 arose from 1824 to 1929, line 6 arose
around 1860, lines 2 and 4 around 1900, line 3 from 1915 to 2002, and lines 7, 8 and 9 from 1936 to 1973.

The 9 lines contain all natural sciences.

They contain physics, chemistry, material science, biology, medicine, geology, astronomy and engineering.

Again: any single observation contradicting the 9 lines will create a sensation.

 
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Three questions are open in fundamental physics.

III    Are all observations in nature described by the 9 lines – or are there phenomena beyond present textbook physics?

For example, to which line do dark matter and dark energy belong exactly?c⁴

II    Are there any undiscovered lines with new physics – or will  F ≤ c⁴/4G  remain the last law of physics?

Explored mainly in the years from 1973 to 2002, the force limit is the law of physics discovered last.⁴
The limit value c⁴/4G ≈ 3.0 · 10⁴³ N for the local force has passed all checks.⁴
It allows deducing Einstein's field equations and is the shortest known summary of general relativity.⁴
Because line 3 on maximum force c⁴/4G was added to the list only recently, a separate web page is dedicated to it.c⁴

IIII    What is the common explanation for the 9 lines – or is there none?c⁴

In particular, what determines the principles in lines 1 to 5?c⁴
And what determines the choices in lines 6 to 9, i.e., the force spectrum, the particle spectrum and the fundamental constants?c⁴
The last four lines contain the only known physics effects unexplained by and thus beyond the standard model.c⁴

Many enjoy searching for answers and some even dedicate their life to it.

 
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This image about how to summarize all sciences in 9 lines, free for reuse, might be useful.

 
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A video summary, by David Tong, of the standard model and of gravitation is found at https://www.youtube.com/watch?v=Unl1jXFnzgo&t=1s.
The mathematical expression in the video can be seen as a (symbolic) combination of the 9 lines.

The 9 lines allow measuring progress towards unification, as told here, together with more notes.

 
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