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Joined 1 year ago
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Cake day: August 19th, 2023

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  • Oh! I had no idea Fedora was officially supporting Flatpaks these days. I used Fedora from when it was Fedora Core 3 in 2004 until about 2015. Since it was the distro I cut my teeth on, I assumed I was familiar, but it’s wild to think it’s been nearly a decade since I’ve used it…

    I completely agree that they should come up with a unified way for managing packages that they officially support. But also, a few years ago, if things weren’t in the default package manager then we had to build them ourselves because they can’t be expected to do everything for us.

    So I don’t think we killed the killer feature. I simply think people have more options these days (although I see how some might see this as more rope with which to hang themselves)

    I’ll update my original post to clarify that I was wrong



  • No. (Or maybe yes. See Edit)

    Ultimately, you are the one that decided to install things outside of your distro’s package manager. If you don’t like what happens as a result… then don’t do that.

    You are completely able to use the built-in package manager to achieve what we had “a few years ago”. If you want something that isn’t available in the package manager you can do what we did “a few years ago” and install it separately yourself (from source, flatpaks, snaps, appimage). Or you could become a package maintainer for that package and get it added as a package for your distro. It’s completely up to you and in no way different frmo what it was a few years ago.

    Edit: after finding out from @mfat@lemdro.id that Fedora does in fact officially support Flatpak, I do indeed think that they could do better in how they support that.



  • It’s unintuitive, but super cool! There’s a great video by Physics Girl and Veritasium that explain it better than I ever could here.

    First, the wavelength of the laser (think of it as the “color” of the laser) is chosen such that the energy of the photons is just under the energy state of the atoms that you are trying to cool.

    Now, when the atom is moving toward the source of the laser, this causes the atom to “see” a higher energy. This is called Doppler shift and is a very well-known effect in anything that emits waves and is moving. In fact, you’ve experienced it before when you hear a car horn – as it moves towards you it has a higher pitch and as it moves away from you it has a lower pitch.

    So, for atoms moving toward the source the see the energy rise just enough to absorb the photon and move to a higher energy state. Inevitably, the atom will want to move to a lower energy state (as all matter does) and will end up ejecting a new photon in a random direction. In order to maintain the conservation of momentum, this means that the photon will likely be ejected in a way that counteracts the direction it was previously moving, effectively slowing it down. Since heat is a measure of how fast atoms are moving, this means that atom has cooled down.

    For atoms moving away from the laser source, they are unable to absorb the photons because the Doppler shift acts in the opposite direction, and they are completely unable to absorb the photons.

    So as a result of all this, it is possible to slow down atoms moving in a very specific direction, without affecting the other atoms. This means you can systematically slow atoms down which means you can systematically cool things down.

    Edit: Here’s a piped link to the youtube video above in case you’re privacy-conscious, however, Dianna (aka Physics Girl) has been bed-ridden with Long COVID for a while now so it would be great if you could contribute to her Patreon in lieu of the ad revenue


    1. It was theorized that light could be a wave way before the double slit experiment. Like, a century before. So no, it wasn’t “assumed light is 100%” quantized before that experiment.

    2. Anything that is a wave can be cancelled, so this idea was baked right into the wave theory of light, they just didn’t have the ability to control light precisely enough to prove it until the double slit experiment. You don’t need quantum mechanics to explain wave theory, it just happened that the double slit experiment, while proving that light behaved like a wave, also showed other characteristics that it was also behaving in a quantized fashion. The fact that light is quantized into photons has nothing to do with the fact that they cancel so you really don’t need quantum mechanics to explain it. The reason light can be cancelled is exactly the same as every other thing in physics that behaves like a wave.

    3. The word quantum comes from the word quantization not “quantify”. Those two words mean different things

    4. Light is a wave. It also happens to be a particle. So the “existence of waves” is not a different subject. It’s exactly this subject

    Edit: Love the snarky edit to a post full of being confidently wrong. I’m going to go engage with others. Good day, sir/ma’am!