zornslemmon

@zornslemmon@mathstodon.xyz

I was a physics and mathematics double major in college and I got my Ph.D. in physics studying galactic cosmic ray electrons. I love brewing beer and watching rugby.

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christianp, to random
@christianp@mathstodon.xyz avatar

Does there exist a satellite with a camera pointed at earth that is detailed enough for it to take a selfie of its reflection in water?

zornslemmon,

@christianp I would bet you could do it from the ISS, since it is so huge. You can take a picture of it from the ground with a DSLR camera so I would bet you could do it from the ISS ( it would appear to be twice as far as it does looking up from the ground, but I bet it is still resolvable). For something not as big as the ISS, say Hubble with a width of about 4 meters, it would appear to be 1000 km away resulting in an angular size of 4/1e6 = 4 microradians. Since Hubble has an angular resolution of 0.27 microradians, it should work as well.

That's all the optics side. If you factor in the reflectance of water and the backscattered light from the atmosphere, I wouldnt surprise me if the reflected image is too dim to see.

zornslemmon, to animals

This is Newton, aka Mr. Newt, aka Newtie-newt. He was 15 years old and a very gentle and loving dog and we had to say goodbye to him today. Our hearts are broken.

He was a very good boy.

johncarlosbaez, (edited ) to random
@johncarlosbaez@mathstodon.xyz avatar

Yesterday I showed you a bunch of cute pictures of tuning systems, like this one.

On the outside you see a 'circle of fifths' with numbers saying how sharp or flat each fifth is. Bigger positive numbers mean more sharp, and I make them brighter green. Bigger negative numbers mean more flat, and I make them brighter red.

Inside there's a 'star of thirds' saying how sharp or flat each major third is. The same rules apply.

Basically, bright colors sound bad. Black is best. You'd like all the numbers to be zero and all the arrows to be black. But that's impossible! It's like lumps in a carpet that's too big for your floor: if you make parts of it nice, other parts get lumpy.

So what's allowed?

(1/n)

zornslemmon,

@johncarlosbaez Hello. I've really been enjoying your pieces on tuning systems. I recently saw this article, which I'm curious whether you saw it, as it brought your posts to my mind: https://www.cam.ac.uk/research/news/pythagoras-was-wrong-there-are-no-universal-musical-harmonies-study-finds

Their paper is at: https://www.nature.com/articles/s41467-024-45812-z

Long_live_rock_n_roll, to music
@Long_live_rock_n_roll@mastodon.world avatar

Any genre, Just join in 😉

#JoinIn #music

zornslemmon,

@Long_live_rock_n_roll I think it was Fragile from Yes, but it might have been Are You Experienced? from The Jimi Hendrix Experience.

johncarlosbaez, (edited ) to random
@johncarlosbaez@mathstodon.xyz avatar

The headline screams

"𝗦𝗶𝗻𝗴𝘂𝗹𝗮𝗿𝗶𝘁𝗶𝗲𝘀 𝗱𝗼𝗻’𝘁 𝗲𝘅𝗶𝘀𝘁,” 𝗰𝗹𝗮𝗶𝗺𝘀 𝗯𝗹𝗮𝗰𝗸 𝗵𝗼𝗹𝗲 𝗽𝗶𝗼𝗻𝗲𝗲𝗿 𝗥𝗼𝘆 𝗞𝗲𝗿𝗿

What's up with that?

As usual, it's less of a big deal than it looks. But Kerr is smart: he's the guy who first found solutions that describe rotating black holes. And the article is nice and clear. So it's more interesting than the usual nothingburger we've come to expect from screaming headlines about fundamental physics.

Kerr is talking about Penrose's famous singularity theorem, the one Penrose won the Nobel prize for. This says roughly that if space is infinite in extent, and light becomes trapped inside some bounded region, and no exotic matter is present to save the day, general relativity predicts that either a singularity or something even more bizarre must occur.

Of course I'm not stating the theorem precisely here. Each of the vague terms I just used must be made precise. But what's Kerr claiming?

Kerr isn't claiming Penrose's result is false. Instead, he's doing two things.

First, he's pointing out that the definition of "singularity" used in the theorem is not the only definition possible. A "curvature singularity" is - very roughly - a place where the curvature of spacetime approaches infinity. But that's not the kind of singularity that Penrose was talking about! Instead, he was talking about a place where the path of a particle can suddenly end. This may or may not be a curvature singularity.

This is not news.

Second, Kerr is arguing that rotating black holes have some singularities in Penrose's sense that aren't curvature singularities. Unfortunately this argument seems to be wrong.

(1/3)

https://bigthink.com/starts-with-a-bang/singularities-dont-exist-roy-kerr/

zornslemmon,

@highergeometer @johncarlosbaez Perhaps some of the saltiness in his deleted response and arXiv paper can be put in context with an interesting backstory provided by Kerr and provided by a response in that SE thread. It seems he feels that he was done wrong by Hawking (and maybe Penrose) 50+ years ago, and also feels they are wrong, and if so, I imagine having Hawking lauded as one of the smartest people of all time and Penrose getting the Nobel might be a long term irritant for him.

https://physics.stackexchange.com/a/791500

gnitro, to beer
@gnitro@urusai.social avatar

Went to #ChesapioocRealAleBrewery today with @Zarf

7 out of 8 beers were hits. That's a good sign! Usually maybe 50% I enjoy. The new west coast IPA is awesome

@beersofmastodon

#Beer #CraftBeer #mdbeer #drinklocal

zornslemmon,

@gnitro @Zarf @beersofmastodon Holy cow, I was there too. Not part of the birthday party going on, just popped in for a few beers. Had the cream ale, which was a lot fruitier (raspberry?) than I expected it to be.

GayOldTime, to retrogaming
@GayOldTime@masto.ai avatar

Steal his look: Purple cape, bright blue culottes, and green go-go boots. Beard optional.
#RetroGaming #eighties #fashion

zornslemmon,

@GayOldTime I should have gone with that for my wedding party instead of the boring tuxedos we had.

zornslemmon, to beer

This is a very dark beer with quite a bitter finish. It is silky-smooth and you feel a slight warming from the 10% ABV. You do get very noticable unsweetened chocolate notes. Very tasty and I'd buy it again.

#beer #BeersOfMastodon #stout #ImperialStout #BrooklynBrewery

KathyReid, to random
@KathyReid@aus.social avatar

So yeah this just happened at @ACM 🎉

https://twitter.com/ACMEAAMO/status/1719460197893120388

zornslemmon,

@KathyReid @ACM Woo hoo! Congratulations!

neatchee, to Anime
@neatchee@urusai.social avatar

Just got back from watching Suzume. What a wonderful, enchanting movie. Big time Howl's Moving Castle vibes. Amazing imagery and symbolism that leaves room for interpretation, but still conveys a clear deeper meaning than the surface story.

9/10, maybe even 10. Will need to ruminate on that.

#anime #Suzume #SuzumeNoTojimari #movies

It's back in theaters so don't miss it like I did the first time around! https://www.suzume-movie.com/

zornslemmon,

@neatchee I watched this on a plane flight and I really enjoyed it. I recommend it as well.

pieceofthepie, to Corgi
@pieceofthepie@n8e.dev avatar

It's the time of year when we break out the tiny hats.

#SheridanTheCorgi #Corgi #WelshPembrokeCorgi #DogsOfMastodon #Dogs #Pixel6Pro

zornslemmon,

@pieceofthepie Is Sheridan really a secret agent working for O.W.C.A.?

#PerryThePlatypus #PhineasAndFerb

johncarlosbaez, to random
@johncarlosbaez@mathstodon.xyz avatar

Here's a video of my talk "Topology and the Periodic Table".

The "periodic table of n-categories" is a chart showing n-categories that are trivial at the bottom k levels. This helps organize our understanding of higher categories and their relation to topology and physics. There are many ways to hop around the periodic table, and I explain 4 of the main ones: looping, delooping, forgetting monoidal structure and stabilization. I also explain how free k-tuply monoidal categories let us enhance familiar structures such as the natural numbers and integers and obtain such things as braid groups and the homotopy groups of spheres. At the end I explain how to use these ideas to understand the isomorphism π₃(S²)≅ℤ.

(1/2)

https://www.youtube.com/watch?v=_02gCh1TBD0&list=PLuAO-1XXEh0a4UCA-iOqPilVmiqyXTkdJ

zornslemmon,

@johncarlosbaez Out of curiosity, is there a connection between this and to Fano varieties and an attempt to categorize geometry into fundamental basic shapes? I recently saw this article and associated paper and it made me think back to your post:

https://www.popularmechanics.com/science/math/a45533729/periodic-table-of-shapes/

https://www.nature.com/articles/s41467-023-41157-1

miona, to photography

deleted_by_author

    •
    zornslemmon,

    @miona I recently returned from a first-time visit to Japan. I already want to go back!

    standupmaths, to random

    Everyone is reporting on "Air traffic chaos caused by 'one in 15 million' event". https://www.bbc.co.uk/news/business-66723586

    But the report says "This scenario had never been encountered before, with the system having previously processed more than 15 million flight plans" https://www.nats.aero/news/nats-report-into-air-traffic-control-incident-details-root-cause-and-solution-implemented/

    zornslemmon,

    @standupmaths I suppose we're going to have to wait another 30 or so million flight plans to see if that statistic holds up with any reasonable level of confidence.

    zornslemmon, to beer

    It turns out to indeed be both crisp and refreshing.

    #beer #BeersOfMastodon #WaikikiBrewing #HawaiianBeer

    gnitro, to random
    @gnitro@urusai.social avatar

    I just watched In Living Color 1x02 "The Wrath of Farrakhan" https://trakt.tv/shows/in-living-color/seasons/1/episodes/2

    zornslemmon,

    @gnitro If you haven't seen it, add to your to-watch list "I'm Gonna Git You Sucka" It is what the Wayan brothers did before In Living Color. It is funny on its own, but if you are familiar with the blaxploitation genre (Shaft, Cleopatra Jones, etc.), it is a hilarious homage to those. I haven't seen it since I saw it when it came out, and I still remember some of the good lines from it.

    https://www.youtube.com/watch?v=pPvLWLbDVCw

    jaztrophysicist, (edited ) to science French

    "A brief history of time" by Stephen Hawking is probably the most influential semi-popular #science book ever written in #physics, #astrophysics, #cosmology , one that brought generations of students into these fields.

    Do you know of any equivalent books in other fields of science, STEM or other ? Reply ⬇️

    Boosting will make everybody on #Mastodon smarter !

    zornslemmon,

    @jaztrophysicist Darwin's On the Origin of Species and Stephen Jay Gould's Ever Since Darwin (and the books that followed) for biology.

    https://www.gutenberg.org/files/2009/2009-h/2009-h.htm

    flargh, to space
    @flargh@mastodon.social avatar

    As the knives sharpen around the #Luna25 crash I am reminded of the time #NASA crashed into Mars because the #metric system was too much for American subcontractors to deal with.

    https://en.wikipedia.org/wiki/Mars_Climate_Orbiter

    zornslemmon,

    @nyrath @flargh That was also a gross systems engineering failure, in my opinion. It doesn't matter what units anything puts out (everything comes out as voltages and digitally converted numbers anyway). How did that pass systems integration testing? There should have been test cases that verified all of the interfaces between them.

    elizabethtasker, to random
    @elizabethtasker@mastodon.online avatar

    A trip to Toriton Sushi in Sapporo! It’s extremely popular and they now have a queuing system via Line where you scan the QR code on your ticket, go outside and Line notifies you when you’re near the queue head and should go inside and wait.

    Toriton used to be conveyer belt sushi, but you now order on iPads. Truthfully, it’s much more convenient but I sort of miss seeing the sushi plates sailing around. Now the belt just has adverts for the sushi specials!

    Sitting at the seats that surround the conveyer belt. In the middle of the restaurant, the chefs are at work. Customers are seated around them. An iPad for ordering is in my area, along with two plates of sushi.
    Two more plates! One is fried squid tentacles!

    zornslemmon,

    @elizabethtasker I remember an article about that a while ago. It was certainly related to the teens making videos of themselves messing with the food. If that wasn't the sole reason, I believe it was the straw that broke the camel's back.

    gutenberg_org, (edited ) to books
    @gutenberg_org@mastodon.social avatar

    "Jusqu'au jour où Dieu daignera dévoiler l'avenir à l'homme, toute la sagesse humaine sera dans ces deux mots :
    « Attendre et espérer ! »"
    Le Comte de Monte-Cristo, 1844

    Alexandre Dumas was born in 1802. Many of his historical novels of adventure were originally published as serials, including The Count of Monte Cristo, The Three Musketeers, Twenty Years After and The Vicomte of Bragelonne. via @wikipedia

    Books by Alexandre Dumas at PG:
    https://www.gutenberg.org/ebooks/author/492

    zornslemmon,

    @gutenberg_org Holy cow, with that hair Dumas looks an awful lot like Marty Allen!

    ramsey, to beer
    @ramsey@phpc.social avatar

    Wait. #FatTire is now a golden #ale? When did that happen? What happened to the old recipe? Do they still brew it? #beer

    zornslemmon,

    @ramsey The employees sold out to Kirin in 2019. They changed their packaging and "lightened" their beer to "position themselves as an outdoor brand" and to "attract younger drinkers."

    TheVinylApe, to vinyl
    @TheVinylApe@masto.ai avatar

    BLACK SABBATH
    Sabotage
    1975 Canada pressing

    A little Sunday Sabbath never hurt anyone.
    I friggin’ love Sabotage. The back-to-back punch of Symptom Of The Universe and Megalomania do it for me every time. Not to mention the epic, gnarly closer The Writ.
    It’s almost time to find a new play copy of this, as I’ve had it a long time and have drilled it into the ground.
    I will continue to.
    One of my favorite hard rock records ever.
    #vinyl #vinylrecords #blacksabbath #metal #hardrock #70s #70smusic

    image/png
    image/png

    zornslemmon,

    @cazabon @TheWarlock666 @TheVinylApe
    I've got the LP! Among other things, it has their 12 Beers of Christmas. 😆

    christianp, to random
    @christianp@mathstodon.xyz avatar

    Meta, the company that owns Facebook and Instagram, is reportedly going to launch a new ActivityPub-compatible social network on the domain threads.net.

    I and @ColinTheMathmo, the admins of mathstodon.xyz, are wary of the effect this will have on the fediverse, so we're pre-emptively blocking that domain until we see whether Meta plan on trying to federate, and if so, under what terms they do so.
    Once it becomes clear how threads.net works, we'll decide whether to permanently block it.

    zornslemmon,

    @christianp @ColinTheMathmo A wise course of action, I think. I expect they'll be very good citizens for a while, perhaps even contributing positively by fixing/improving issues like ease of onboarding and UI changes, until they're in the good graces of the largest instances, maybe even hosting them for free. But we all know they only have one business model.

    My long-term prediction is it will follow the XMPP path. There will eventually be some "optional" data fields added to Activity Streams that in addition to adding new features, somehow seem to support things like dropping web beacons too. The larger instances will run the new protocol, particularly the ones directly supported by Meta, but it will coincidentally be not fully compatible with the older versions; not broken, but not easy to exchange info with the new version. Eventually the Fediverse will be faced with either supporting the new version to connect with the larger Fediverse instances, or be cut off.

    zornslemmon, to random

    For the #ShakeTheDanceFloor theme of #TuneTuesday I don't know how you can shake it any harder than the Harlem Congaroo Dancers in the 1941 movie Hellzapoppin'

    https://www.youtube.com/watch?v=dSAOV6XEjXA

    mdmrn, to Nintendo
    @mdmrn@urusai.social avatar

    Okay, so last night I tried to do a inspired photoshoot on . I think the looks, lighting, and even the props work, but the background needs work.

    I may need to make a The Matrix style custom design or find one.

    Either way, Raynond is Neo!

    Thoughts on how to improve this scene appreciated!

    🏷 Tags: #あつもり #あつ森

    zornslemmon,

    @mdmrn That looks really nice.

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