Ciro Santilli @cirosantilli 40

Hyperthreding is the Intel brand-name, TODO generic name.

It is not a practical fighting style. But it is an awesome game/exercise.

TODO why it is optimal: physics.stackexchange.com/questions/149214/why-is-the-carnot-engine-the-most-efficient

The key question is: why is this not symmetrical?

One answer is: because one of the twin accelerates, and therefore changes inertial frames.

But the better answer is: understand what happens when the stationary twin sends light signals at constant time intervals to each other. When does the travelling twin receives them?

By doing that, we see that "all the extra aging happens immediately when the twin turns around":

Another way of understanding it is: you have to make all calculations on a single inertial frame for the entire trip.

Supposing the sibling quickly accelerates out (or magically starts moving at constant speed), travels at constant speed, and quickly accelerates back, and travels at constant speed setup, there are three frames that seem reasonable:

If you do that, all three calculations give the exact same result, which is reassuring.

Another way to understand it is to do explicit integrations of the acceleration: physics.stackexchange.com/questions/242043/what-is-the-proper-way-to-explain-the-twin-paradox/242044#242044 This is the least insightful however :-)

Bibliography:

Let's show them how it's done with primes + awk. Edit. They have a -d option which also shows gaps!!! Too strong:gives us the list of all twin primes up to 100:Tested on Ubuntu 22.10.

Examples at: two-js/.

JavaScript library, works both on browser and headless with Node.js to SVG.

Feels good. Maybe not ultra featured, and could have more simple examples in docs, but still good.

Vs Paper.js github.com/jonobr1/two.js/issues/319

One of the main features of Two.js appears to be the fact that it can natively render to either SVG and canvas, rather than creating SVG through DOM hacks as done by other projects.