Senior Wrangler Updated +Created
Wooden spoon (award) Updated +Created
Intel manual Updated +Created
Although it is impossible to understand without examples in mind, try to get familiar with the manuals as soon as possible.
Specially interesting is Figure 4-4 "Formats of CR3 and Paging-Structure Entries with 32-Bit Paging", which gives the key data structures.
Length contraction Updated +Created
Suppose that a rod has is length measured on a rest frame (or maybe even better: two identical rulers were manufactured, and one is taken on a spaceship, a bit like the twin paradox).
Question: what is the length than an observer in frame moving relative to as speed observe the rod to be?
The key idea is that there are two events to consider in each frame, which we call 1 and 2:
  • the left end of the rod is an observation event at a given position at a given time: and for or and for
  • the right end of the rod is an observation event at a given position at a given time : and for or and for
Note that what you visually observe on a photograph is a different measurement to the more precise/easy to calculate two event measurement. On a photograph, it seems you might not even see the contraction in some cases as mentioned at en.wikipedia.org/wiki/Terrell_rotation
Measuring a length means to measure the difference for a single point in time in your frame ().
So what we want to obtain is for any given time .
In summary, we have:
By plugging those values into the Lorentz transformation, we can eliminate , and conclude that for any , the length contraction relation holds:
The key question that needs intuitive clarification then is: but how can this be symmetric? How can both observers see each other's rulers shrink?
And the key answer is: because to the second observer, the measurements made by the first observer are not simultaneous. Notably, the two measurement events are obviously spacelike-separated events by looking at the light cone, and therefore can be measured even in different orders by different observers.
OpenCourseWare Updated +Created
Webcam Updated +Created
Encyclopedia Britannica Updated +Created
Ciro Santilli is old enough to remember his parents whispering its name with a respectful tone.
Genius: Richard Feynman and Modern Physics by James Gleick (1994) mentions several times how Richard Feynman was a reader of the encyclopedia. E.g. in youtu.be/ivxkd98mDvc?t=50 Richard's sister also talks about it.
Then the Internet came along and killed it.
The motivation model for collaborators was simple: to get famous. To be able to be selected contribute an article meant that you knew something or two! There was some physicist Ciro read the biography of who was really glad to be able to write an article on the encyclopedia after having worshiped it for so long, TODO find the reference.
While this is somewhat a part of Wikipedia motivation, it is much less so because there is no single article authorship. This is something OurBigBook.com aims to improve.
Unordered tree Updated +Created
XMPP Updated +Created
Khan Academy Updated +Created
Kudos for being a not-for-profit. Also, anyone can create content: e-learning websites must allow students to create learning content. Oh, but TODO is possible for anyone to make content publicly visible? Course join links lik: www.khanacademy.org/join/MJZ6NSV7 require login. webapps.stackexchange.com/questions/165132/how-to-create-a-course-that-is-publicly-visible-without-the-need-to-login-on-kha If that's the case, it is a fatal flaw not shared by OurBigBook.com.
Another cool aspect is that they have the "physical world teacher pull student accounts in" approach built-in quite well at course creation. This is a very good feature.
As of 2021 they were a bit struggling for money it seems: www.youtube.com/watch?v=I8XdUy-wyyM?
Potentiometer Updated +Created
Messier object Updated +Created
What an awesome list the dude compiled. Contains many of the features we care the most about of the sky, since of course, apparent magnitude is a big determinant of that.
Planetary system Updated +Created
Brain-computer interface company Updated +Created
Wireless Updated +Created
Global Positioning System Updated +Created
They actually carry atomic clocks in them.
Devboard battery power Updated +Created
Many devborads require a 5V power supply.
This is common on wall transformers and USB, but not in batteries.
For battery power you need a transformer.
Video 1.
Raspberry Pi Battery Power by ExplainingComputers (2021)
Source.
Johann Joseph Loschmidt Updated +Created
Fictional pornography depicting minors Updated +Created
This is the kind of mind-bending argument twists that Ciro Santilli loves. If we take out the "a real child is hurt" aspect, does it still make sense to make it illegal?
Of course, hentai of young-looking girls has already existed since forever. Bit with newer image generation methods in the 2020s used for computer generated child pornography, especially sometimes photorealistic text-to-image generation, things are taken to another level.

There are unlisted articles, also show them or only show them.