Topics (196k) Articles (198k) Users (296) Discussions (237) Comments (383) Files (715) New article
Each side is a sphere section. They don't have to have the same radius, they are still simple to understand with different radiuses.
The two things you have to have in mind that this does are:
- This is for example why you can use lenses to burn things with Sun rays, which are basically parallel.Conversely, if the input is a point light source at the focal length, it gets converted into parallel light.
- image formation: it converges all rays coming from a given source point to a single point image. This amplifies the signal, and forms an image at a plane.The source image can be far away, and the virtual image can be close to the lens. This is exactly what we need for a camera.
Published as "Fine Structure of the Hydrogen Atom by a Microwave Method" by Willis Lamb and Robert Retherford (1947) on Physical Review. This one actually has open accesses as of 2021, miracle! journals.aps.org/pr/pdf/10.1103/PhysRev.72.241
Microwave technology was developed in World War II for radar, notably at the MIT Radiation Laboratory. Before that, people were using much higher frequencies such as the visible spectrum. But to detect small energy differences, you need to look into longer wavelengths.
This experiment was fundamental to the development of quantum electrodynamics. As mentioned at Genius: Richard Feynman and Modern Physics by James Gleick (1994) chapter "Shrinking the infinities", before the experiment, people already knew that trying to add electromagnetism to the Dirac equation led to infinities using previous methods, and something needed to change urgently. However for the first time now the theorists had one precise number to try and hack their formulas to reach, not just a philosophical debate about infinities, and this led to major breakthroughs. The same book also describes the experiment briefly as:
Willis Lamb had just shined a beam of microwaves onto a hot wisp of hydrogen blowing from an oven.
It is two pages and a half long.
They were at Columbia University in the Columbia Radiation Laboratory. Robert was Willis' graduate student.
Previous less experiments had already hinted at this effect, but they were too imprecise to be sure.
The process that imports proteins encoded in the nuclear DNA and made in the cytosol into the mitochondria.
Power, Sex, Suicide by Nick Lane (2006) suggests that proteins are somehow tagged with extra amino acids for this.
Mitochondria have DNA because they need to be controlled individually by 
Ciro Santilli 40 Updated 2025-07-16
Ciro Santilli 40 Updated 2025-07-16Argued at Power, Sex, Suicide by Nick Lane (2006) page 212.
Basically, energy supply has to be modulated rather quickly, because we spend a lot sometimes, and very little other times.
Even not turning it off quickly enough is a problem, as it starts to generate free radicals which fuck you up.
If control came from the nucleus, it has no way to address different mitochondria. But it might be that only one of the mitochondria needs the change. If the nucleus tells all mitochondria to stop producing when only one is full, the others are going to say: "nope, I'm not full, continue producing!" and the one that need to stop will have its signal overridden by the others.
Wikipedia mentions "Since animal mtDNA evolves faster than nuclear genetic markers" with a few sources.
Some sources:
- Power, Sex, Suicide by Nick Lane (2006) page 361 mentions:so this property is also important for the human mitochondrial molecular clock.
While nuclear DNA can barely distinguish between chimps and humans, the mitochondrial clock ticks fast enough to reveal differences accumulating over tens of thousands of years
- www.ncbi.nlm.nih.gov/pmc/articles/PMC3350313 says it for metazoans
- www.quora.com/Why-does-mitochondrial-DNA-mutate-faster
DNA stuff at: human mtDNA.
Big companies manage to publish white papers in peer reviewed journals by Ciro Santilli 40 Updated 2025-07-16
Ciro Santilli 40 Updated 2025-07-16Big companies like Google are able to publish white papers as peer reviewed papers just due to their reputation, e.g. without giving any source code that is central for the article.
It is insane.
E.g.: AlphaGo is closed source but published as www.nature.com/articles/natnure16961 in 2016 on Nature.
This is some fishy, fishy business.
Has some good mentions, but often leaves you wanting more details of how certain things happened, especially the early days stuff.
Does however paint a good picture of several notable employees, and non-search projects from the early 2000's including:
- the cook dude
- porn cookie guy
- the unusual IPO process
Paints a very positive picture of the founders. It is likely true. They gave shares generously to early employees. Tried to allow the more general public to buy from IPO, by using a bidding scheme, rather than focusing on the big bankers as was usual.
The introduction mentions that Google is very interested in molecular biology and mining genetics data, much like Ciro Santilli! Can't find external references however...
Two of the most compelling areas that Google and its founders are quietly working on are the promising fields of molecular biology and genetics. Millions of genes in combination with massive amounts of biological and scientific data are an excellent match for the Google search engine, the tremendous database the company has in place, and its immense computing power. Already, Google has downloaded a map of the human genome and is working closely with biologist Dr. Craig Venter and other leaders in genetics on scientific projects that may lead to important breakthroughs in science, medicine, and health. In other words, we may be heading toward a time when people can google their own genes.
The book gives good highlight as to why Google became big: search was just an incredibly computationally intensive task. From very early days, Largey were already making up their own somewhat custom compute systems from very early days, which naturally led into Google custom hardware later on. Google just managed to pull ahead on the reinvest revenue into hardware loop, and no one ever caught them back. This feels more the case than e.g. with Amazon, which notoriously had to buy off dozens of competitors to clear the way.
Cover of The Google Story
. Ciro Santilli once talked to a man who had been working on high-frequency trading for the last six years.
He was quite nice.
Ciro asked him in what way did he feel his job contributed to the benefit of society.
He replied that it didn't contribute at all. It was completely useless. More than that, it so completely useless, that it was even pure. A bit like advanced mathematics, but not even providing beauty for anybody outside of the company, since everything is a closely guarded trade secret, unlike mathematics which is normally published for the vanity recognition.
And so, Ciro was enlightened.
Pinned article: Introduction to the OurBigBook Project
Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
Intro to OurBigBook
. Source. We have two killer features:
- topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculusArticles of different users are sorted by upvote within each article page. This feature is a bit like:
- a Wikipedia where each user can have their own version of each article
- a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
Figure 1. Screenshot of the "Derivative" topic page. View it live at: ourbigbook.com/go/topic/derivativeVideo 2. OurBigBook Web topics demo. Source. - local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
- to OurBigBook.com to get awesome multi-user features like topics and likes
- as HTML files to a static website, which you can host yourself for free on many external providers like GitHub Pages, and remain in full control
Figure 2. You can publish local OurBigBook lightweight markup files to either OurBigBook.com or as a static website.
Figure 3. Visual Studio Code extension installation.
Figure 5. . You can also edit articles on the Web editor without installing anything locally. Video 3. Edit locally and publish demo. Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension. 
- Infinitely deep tables of contents:
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact