Happy my birthday to those who celebrate.
Uncategorized
2
Posts
2
Posters
1
Views
-
Happy my birthday to those who celebrate.
-
Happy my birthday to those who celebrate.
@monsieuricon thanks! And to you, too!
Gli ultimi otto messaggi ricevuti dalla Federazione
-
Is the Theory of Special Relativity Wrong?
There’s an adage coined by [Ian Betteridge] that any headline ending in a question mark can be answered by the word “No”. However, Lorentz invariance – the theory that the same rules of physics apply in the same way in all frames of reference, and an essential component of special relativity – has been questioned for some time by researchers trying to unify general relativity and quantum field theory into a theory of quantum gravity. Many theories of quantum gravity break Lorentz invariance by giving photons with different energy levels very slightly different speeds of light – a prediction which now looks less likely since researchers recently analyzed gamma ray data from pulsed astronomical sources, and found no evidence of speed variation (open-access paper).
The researchers specifically looked for the invariance violations predicted by the Standard-Model Extension (SME), an effective field theory that unifies special relativity with the Standard Model. The variations in light speed which it predicts are too small to measure directly, so instead, the researchers analyzed gamma ray flare data collected from pulsars, active galactic nuclei, and gamma-ray bursts (only sources that emitted gamma rays in simultaneous pulses could be used). Over such great distances as these photons had traveled, even slight differences in speed between photons with different energy levels should have added up to a detectable delay between photons, but none was found.
This work doesn’t disprove the SME, but it does place stricter bounds on the Lorentz invariance violations it allows, about one and a half orders of magnitude stricter than those previously found. This study also provides a method for new experimental data to be more easily integrated into the SME. Fair warning to anyone reading the paper: the authors call their work “straightforward,” from which we can only conclude that the word takes on a new meaning after a few years studying mathematics.
If you want to catch up on relativity and Lorentz invariance, check out this quick refresher, or this somewhat mind-bending explanation. For an amateur, it’s easier to prove general relativity than special relativity.
Top image: Crab Pulsar, one of the gamma ray sources analysed. (Credit: J. Hester et al., NASA/HST/ASU/J)
-
Brescia: giornata di azioni antisfratto promosse da “diritti per tutti”
@anarchia
Lotta per la casa. Giornata di mobilitazione contro gli sfratti il 15 gennaio 2026 con attiviste e attivisti dell’Associazione Diritti per tutti di Brescia impegnati in tre azioni https://www.rivoluzioneanarchica.it/brescia-giornata-di-azioni-antisfratto-promosse-da-diritti-per-tutti/
-
Signal, the private messaging app.
Curious to see what the uptake is on Fedi.
#poll #signalApp
-
Hey, all! Thank you very much for the responses. I'm one year or more. We started a program a few years ago, partly to engage our kids in cooking. They had a lot of fun, and the food was healthy and tasty. But we all kind of drifted away from it, and when the company wanted a bigger commitment, we just cancelled the program.
-
@52fighters How to implement something turnkey would vary dramatically with _what_ you want to self host.
I've been so far down this rabbit hole for so long I don't know what a typical non-technical user needs or wants. I'm guessing it varies person to person.
@vkc @Meznor
-
@mattiagiovanetti ottimo motivo.
-
@old_hippie @vkc If you want newbie and hassle free experience then yunohost is really good option.
I have really little experience but had to look after freebsd server 5+ years ago, last year decided to make media server and try out yunohost...
If Freebsd is your typical Linux experience then Yunohost is your any modern appstore experience. Install from recommended and 90% already done with 10% the extra management you should do (some are for security reasons as well).
So depending on your needs you might look at other options as yunohost skips most of the hassles setting up server has but from managing Freebsd, understanding Linux on deper level(or having good guides explaining what is what) is really useful when things go wrong.
-
@vkc @daria I'd love to hear/read your thoughts on Pangolin - what do you host behind it, how do you find administering it, etc. I've got a couple services (#TandoorRecipes!) I'd like to share with people who I don't necessarily want to have to run Wireguard for...
