Black holes nearest to the Sun by Ciro Santilli 34 Updated +Created
Interesting to note that there are quite a few nearer than Sagittarius A, as of 2022 we know of one at 1.5 kly: universemagazine.com/en/discovered-the-closest-black-hole-to-the-sun/
It is interesting that a few months earlier there seemed to be no known specific black holes in the Milky Way: www.nasa.gov/feature/goddard/2022/hubble-determines-mass-of-isolated-black-hole-roaming-our-milky-way-galaxy although their count is estimated to be in the hundreds of millions.
For comparison, remember that the Milky Way is 185 kly in diameter x 2 kly thick.
Blaise Pascal by Ciro Santilli 34 Updated +Created
Good film about him: Blaise Pascal (1972).
Good quote from his Les Provinciales (1656-57) Letter XII, p. 227:
The war in which violence endeavours to crush truth is a strange and a long one.
All the efforts of violence cannot weaken truth, but only serve to exalt it the more.
The light of truth can do nothing to arrest violence; nay, it serves to provoke it still more.
When force opposes force, the more powerful destroys the less; when words are opposed to words, those which are true and convincing destroy and scatter those which are vain and false; but violence and truth can do nothing against each other.
Yet, let no one imagine that things are equal between them; for there is this final difference, that the course of violence is limited by the ordinance of God, who directs its workings to the glory of the truth, which it attacks; whereas truth subsists eternally, and triumphs finally over its enemies, because it is eternal, and powerful, like God Himself.
French version reproduced at: www.dicocitations.com/citation/auteurajout35106.php.
Blaise Pascal (1972) by Ciro Santilli 34 Updated +Created
BLAST (biotechnology) by Ciro Santilli 34 Updated +Created
BLAST is a sequence alignment.
The NCBI free-to-use BLAST server: blast.ncbi.nlm.nih.gov/Blast.cgi. Having a centralized query server is fundamental, because the gain of sequence alignment really comes from having one huge database to link information together, which is best centralized.
Bloch sphere by Ciro Santilli 34 Updated +Created
A more concrete and easier to understand version of it is the more photon-specific Poincaré sphere, have a look at that one first.
Blockchain by Ciro Santilli 34 Updated +Created
Blockchain.info by Ciro Santilli 34 Updated +Created
TODO who owns it? Are they reliable?
This helper dumps a transaction JSON to a binary:
bitcoin-tx-out-scripts() (
    # Dump data contained in out scripts. Remove first 3 last 2 bytes of
    # standard transaction boilerplate.
    h="$1"
    echo curl "https://blockchain.info/tx/${h}?format=json" |
    jq '.out[].script' tmp.json |
    sed 's/"76a914//;s/88ac"//' |
    xxd -r -p > "${h}.bin"
)
Block reward by Ciro Santilli 34 Updated +Created
Blog comment hosting service by Ciro Santilli 34 Updated +Created
Bohr model by Ciro Santilli 34 Updated +Created
Was the first model to explain the Balmer series, notably linking atomic spectra to the Planck constant and therefore to other initial quantum mechanical observations.
This was one of the first major models that just said:
I give up, I can't tie this to classical physics in any way, let's just roll with it, OK?
It still treats electrons as little points spinning around the nucleus, but it makes the non-classical postulate that only certain angular momentums (and therefore energies) are allowed.
Bibliography:
Boitatech by Ciro Santilli 34 Updated +Created
Some people from them contacted Ciro Santilli after Ciro's initial publishing of CIA 2010 covert communication websites.
After a quick Discord chat with them, it was apparent that these people were really cool and knowledgeable.
Also many of them seem to think university is broken and just go hack straigh away.
A perfect example of a dojo learning model.
Also they don't seem to need sleep. Go figure!
With pepole like this, there's hope for Brazil: Section "What poor countries have to do to get richer".
Boltzmann constant by Ciro Santilli 34 Updated +Created
This is not a truly "fundamental" constant of nature like say the speed of light or the Planck constant.
Rather, it is just a definition of our Kelvin temperature scale, linking average microscopic energy to our macroscopic temperature scale.
The way to think about that link is, at 1 Kelvin, each particle has average energy:
per degree of freedom.
This is why the units of the Boltzmann constant are Joules per Kelvin.
For an ideal monatomic gas, say helium, there are 3 degrees of freedom. so each helium atom has average energy:
If we have 2 atoms at 1 K, they will have average energy , and so on.
Another conclusion is that this defines temperature as being proportional to the total energy. E.g. if we had 1 helium atom at 2 K then we would have about energy, 3 K and so on.
This energy is of course just an average: some particles have more, and others less, following the Maxwell-Boltzmann distribution.
Bookdown by Ciro Santilli 34 Updated +Created
Written in R, but also relies on pandoc, so quite bad dependency wise.
Cross files references to IDs: yes. But no check by default for duplicates when doing automatic ID from title. Just automatically disambiguates with -1, -2 suffixes, and links take the last one available.
Source page splitting: splits at h2 by default. If configurable, likely always af fixed level?
Has some nice image generation from inline code from standard R plotting functions.
Hello world on Ubuntu 23.04 after installing R:
sudo R -e 'install.packages("bookdown")'
git clone https://github.com/rstudio/bookdown-demo
cd bookdown-demo
Rscript -e 'bookdown::render_book("index.Rmd")'
xdg-open _book/index.html
The build CLI comes from: stackoverflow.com/questions/50888871/how-to-use-rscript-command-line-tool-to-build-a-book-in-bookdown
The installatoin Rscript -e 'bookdown::render_book("index.Rmd")' takes several minutes, it compiles a bunch of stuff from source apparently. but it did work.
Book of Genesis by Ciro Santilli 34 Updated +Created
BookofProofs by Ciro Santilli 34 Updated +Created
No open signup it seems. TODO CV of owner.
BookStack by Ciro Santilli 34 Updated +Created
Video 1.
10k GitHub Stars by BookStack (2022)
Source. Answering to an AMA unfortunately :-) But some OK small bits of information trickled through.
Boston Dynamics by Ciro Santilli 34 Updated +Created
Pinned article: ourbigbook/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!
Video 1.
Intro to OurBigBook
. Source.
We have two killer features:
  1. 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-calculus
    Articles 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/derivative
    Video 2.
    OurBigBook Web topics demo
    . Source.
  2. 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:
    • 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
    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.
    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.
    Video 4.
    OurBigBook Visual Studio Code extension editing and navigation demo
    . Source.
  3. https://raw.githubusercontent.com/ourbigbook/ourbigbook-media/master/feature/x/hilbert-space-arrow.png
  4. Infinitely deep tables of contents:
    Figure 6.
    Dynamic article tree with infinitely deep table of contents
    .
    Descendant pages can also show up as toplevel e.g.: ourbigbook.com/cirosantilli/chordate-subclade
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