Matt Panhans @mpanhans@librem.one

Einstein realized that gravity is due to the curvature of spacetime, but earlier mathematicians had guessed that it's due to the curvature of space.

On the 18th of August 1869, the eminent mathematician Sylvester gave a speech arguing that mathematics is not separate from physics. He later published this speech in the journal Nature, and added a footnote raising the possibility that space is curved:

“the laws of motion accepted as fact, suffice to prove in a general way that the space we live in
is a flat or level space [...], our existence therein being assimilable to the life of the bookworm in a flat page; but what if the page should be undergoing a process of gradual bending into a curved form?”

Then, even more dramatically, he announced that the mathematician Clifford had been studying this!

“Mr. W. K. Clifford has indulged in more remarkable speculations as the possibility of our being able
to infer, from certain unexplained phenomena of light and magnetism, the fact of our level space
of three dimensions being in the act of undergoing in space of four dimensions (space as
inconceivable to us as our space to the supposititious bookworm) a distortion analogous to the
rumpling of the page.”

This started a flame war in Nature which the editor eventually shut off. Clifford later wrote about his theories in a famous paper:

https://en.wikisource.org/wiki/On_the_Space-Theory_of_Matter

But now I hear that maybe Clifford even did experiments to TEST his ideas by measuring the polarization of the skylight during a solar eclipse in Sicily on December 22, 1870:

• S. Galindo and Jorge L. Cervantes-Cota, Clifford's attempt to test his gravitation hypothesis, https://arxiv.org/abs/1807.09230

The amazing prehistory of general relativity!

Welcome to the Public Domain, THE MALTESE FALCON (1930) 🦅💎

🕵️ Sam Spade is on the Case of the Disappearing Copyright as The Maltese Falcon novel joins the public domain.

Learn more ➡️ https://blog.archive.org/public-domain-day-2026/

#PublicDomainDay #CopyrightFree

@kupac

I can speak to if (x) { ... } as I was one of the drivers to make length(x) > 1 an error. It had been a warning since 2002 (saying only x[1] was used), and we made a serious push for escalating that to an error in 2017. It became a strict error in R (>= 4.2.0) [2022-04-22]. You can read about this journey in https://github.com/HenrikBengtsson/Wishlist-for-R/issues/38 and https://blog.r-project.org/2018/10/12/conditions-of-length-greater-than-one/index.html.

1/

RE: https://mastodon.social/@_elena/113667636910565210

Good morning Fedi friends! Today is the 1 year anniversary of the start of my #selfhosting adventures with #YunoHost.

I'm currently self-hosting #GoToSocial, #Pixelfed, #PeerTube and #NextCloud – and I'm always on the lookout for the next great app to install.

Thank you @yunohost for making me a more empowered digital citizen 💖

To give back, I'm writing a simple #selfhosting guide for newbies. ICYMI, here's the latest chapter: https://blog.elenarossini.com/a-newbies-guide-to-self-hosting-with-yunohost-part-2-installation-setup/

Wishing you all a great day!

Journal: Installing web apps

Here’s an HTML web component you can use if you’re participating in the origin trial for the Web Install API.

🔗https://adactio.com/journal/22278

*taps the sign*

@mpanhans @techlore @xmpp the proof that WhatsApp is based on Xmpp and using ejabberd can be found here by the way: https://web.archive.org/web/20230316112202/http://lists.jabber.ru/pipermail/ejabberd/2009-June/005027.html