Nick @internic@social.cleverlibre.org

Without any electronic equipment, piano tuners can tell if two strings are vibrating at almost but not quite the same frequency. They do it by listening for 'beats' - pulsations in loudness.

How does this work? If you add two sine waves of slightly different frequencies, say sin(ωt) and sin(ω't), they will add up and be loud for a while, but then drift out of synch and cancel out for a while. Then they'll drift back into synch and get loud again, etc.

There's even a formula for this:

sin(ωt) + sin(ω't) = 2 sin((ω+ω')t/2) cos((ω-ω')t/2)

We get a sine wave whose frequency is the average (ω+ω')/2, slowly pulsing because it's multiplied by a cosine wave with the low frequency (ω-ω')/2.

I got the animated gif from here:

https://ophysics.com/waves10.html

If you go there and choose ω = 500 hertz and ω = 510 hertz, you can hear nice pulsations at 10 hertz: that is, ten times a second.

Mickey Mouse Horror Movie Trailer Drops: Film Uses ‘Steamboat Willie’ Version Of Character That’s Now In Public Domain https://deadline.com/2024/01/mickey-mouse-horror-movie-trailer-mickeys-mouse-trap-1235693579/

This is a nice look at Lagrange points and all the spacecraft that are hanging out in these stable islands where the gravity from the Earth & Sun balance each other out https://www.scientificamerican.com/article/indias-aditya-l1-space-probe-heads-for-gravitational-island/

Thirty years ago, I used the holidays to rewrite our in-house 3d tool from scratch, based on specs and design I worked on for a year. On January 2nd 1994, the first version was running!
I'm incredible proud, humbled and impressed of where it went. Happy 30th birthday :) #b3d

lol at people trying to retcon history and pretend the Y2K bug wasn't real.

I literally worked for like a year from late 1998 to the end of 1999 to fix databases of utility companies and health systems to not, you know, completely and utterly fail come January 1st, 2000.

@robertatcara As someone who personally discovered and fixed bugs that would have had significant real world impact, it is disturbing to hear someone propagate this myth. And it is a myth.

https://time.com/5752129/y2k-bug-history/

The testing methodology insured that these impacts were not hypothetical. At my company, the testing was performed by "actually rolling the clock forward* on test. systems to see what would happen. For example, I discovered that every ATM in the state of Alaska operated by my company would have locked up until a chip was swapped. Someone had to fly all over the state to proactively swap the chip beforehand, to avoid significant customer impact.

And that was just one story. I personally oversaw investigation and fixes for other hardware and software at that company that would have failed.

And that was just my company. I spoke with others in IT at that time with similar stories. And that was just the people I knew.

So no, it wasn't "a big fuss about nothing" - and saying so is both dangerously revisionist, and disrespectful of the work it took to prevent real impacts.

Can we just stop using Discord and go back to using forum sites?

I realize it's (comparatively) super easy to set up, but y'all realize it's just going to bite us all in the ass as soon as someone at Discord decides they need to turn up the profit ratio?

It's a ticking time bomb. The whole thing is going to follow the enshittification process, and anything of value on there is going to be lost/sold/destroyed. Y'all are just feeding the monster.

Happy birthday to everyone working in security! 🥳

As a believer in the motivational power of streaks (thanks, Duolingo), massive respect to @tomscott who just ended a ten year streak of posting a video to YouTube once a week (and gained over 6 million subscribers in the process)

His sign-off video is an extremely stylish way to go out https://www.youtube.com/watch?v=7DKv5H5Frt0

Obligatory #psychology post about motivation for new years resolutions, some stuff I've learned both as a psych researcher and this year as a person trying to stay committed to very complex rehab!

- when we say set attainable goals WE MEAN IT! Cut the goal in half. Ambition is the mind-killer. Attainable is the recursive motivation feeder.
- mindful tracking means make it easy for yourself to see your effort, not fixate on outcomes
- we overestimate the cost of lapse, remind yourself of this

One of the most important times to wear a mask is after you have attended a large gathering.

Wastewater data suggests there was a 50%+ chance you encountered someone with COVID if you attended an event with 20+ people.

You can transmit COVID before you develop symptoms, so now is a good time to wear a mask.

(Chart: Dr. Mike Hoerger)

That's my 2024 cheesy post, but something that warmed my heart in 2023 was mentoring students & young scholars, helping academics with funding and jobs, and in turn finding people helping, supporting and mentoring me.

Nobody needs a lot of publications but everybody needs kindness.

I timed AFTER THE THIN MAN on Max (formerly HBO Max) so the new year would strike simultaneously on film and in real life.

After it did, I paused. When I restarted, I got this message.

A good reminder for 2024: physical media doesn’t disappear at midnight.

#FilmMastodon #PhysicalMedia

Small thing:

So, during the last few years everything got sacrificed to getting A City on Mars done at the quality level we wanted. Even like, gardening, weekends, vacation. But also doing my comic with the level of patience I want. Currently breaking the habit of trying to finish up my writing as fast as possible, but it's hard.

Anyway, today's comic is the first comic I've made in a good while that makes me giggle every time I read it. Bodes well for 2024!

Edwin Hubble announced #OTD in 1925 that Andromeda and other spiral nebulae were in fact separate galaxies outside the Milky Way, in a paper read to an AAS meeting by H.N. Russell.

The Universe was far larger than what many astronomers had allowed themselves to imagine. It was more than just our little island of stars.

Hubble built on observations by Vesto Slipher, collaborated with Milton Humason, and relied on Henrietta Swan Leavitt’s Cepheid variable work to reach this conclusion.

Especially in tech, I often hear folks fear that providing a more supportive evaluation situation will weaken its accuracy. In other words, nice interviewers may make people feel good, but at the cost of us risking a bad hire.

This is actually counter to much of the science of evaluation! The fact that people perform *better* in the presence of social support is often *because it has become a more true evaluation of skills*!

The balloon launch of mission 736N carrying the #GUSTO (Galactic / Extragalactic ULDB Spectroscopic Terahertz Observatory) occurred at about 6:35 UTC on December 31, 2023.

Now the #balloon is slowly ascending crossing 70.000 ft.
Real-time tracking (updated every 15 minutes) is available at: https://www.csbf.nasa.gov/map/balloon8/flight736N.htm

On-board camera showing the ascent via Line-Of-Sight link while it is near McMurdo station: https://video.ibm.com/channel/nasa-csbf-ldsd

Images of the launch by Hayden Boyd and Corey Weber
#NASA

May 2024 be the year that software management conversations finally discover the notion of heterogeneity of effects

Since everyone else has been having a go, here's my New Year's Eve attempt at a colour image of Jupiter's volcanic moon, Io.

From the data taken by NASA's Juno mission during its 30 December 2023 flyby.

Am quite pleased with how it came out, though I'm a long way from competing with the true planetary imaging masters 🙂👍

Will upload to Flickr later on.

Credit: NASA / JPL-Caltech / SwRI / MSSS / Mark McCaughrean

#Astrodon #Astronomy #SpaceScience #JunoMission #SpaceRocks