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Cake day: June 26th, 2023

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  • vithigar@lemmy.catoScience Memes@mander.xyzOxygen
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    14 days ago

    The short version is that life needs something that’s at least a little unstable in order to extract chemical energy from things.

    The post is correct when viewed in a particular light, on a technicality, if you squint. By that same technicality iron rusting is also burning very slowly. They’re ignoring the rapidity which is implied by “burning”. But yes, oxygen is unstable, oxygen helps burn things, and oxygen is toxic if you get too much at once. Though you’d need to be breathing pure oxygen pressurized to about 1.4 atmospheres, or regular air pressurized to about 7 atmospheres, for that last one to happen. It’s a legitimate concern for deep SCUBA divers.

    But why does life need instability? Chemical instability is, in basic terms, just stored chemical energy, and that energy wants to be released. The more reactive something is the easier it is to get energy from reactions involving it. There’s a balancing act here where more reactive means easier energy, but also more dangerous. Oxygen is in a kind of sweet spot where it’s stable enough that it’s not generally going to explode or catch fire on its own, but can be coaxed into doing those things in controlled ways with other chemicals to extract energy when needed.




  • Yes, if you consider just a human-mass equivalent portion of the Sun then it’s not doing much, but that’s not really a useful comparison. We’re talking about total net entropy here, not entropy per unit mass.

    But yes, if it makes you feel any better, I’ll concede that if you had octillions of people our total metabolic energy output would, in fact, be significantly higher than that of the Sun.






  • vithigar@lemmy.catoScience Memes@mander.xyz8 Minutes
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    2 months ago

    Would it? What does “stationary” mean when discussing relative velocities? The mirror being stationary and the person firing the photon moving at a constant velocity is literally an indistinguishable scenario from a stationary person firing the photon at a moving mirror.

    If I am moving relative to a mirror when I fire the photon, then the mirror is moving relative to me, and will be in a different relative position by the time the “event” of my firing that photon reaches it.

    Also, the photon isn’t moving infinitely fast in my (the firer’s) reference frame. It’s moving infinitely fast in it’s own reference frame.


  • vithigar@lemmy.catoScience Memes@mander.xyz8 Minutes
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    2 months ago

    The observable effect is the same either way. If light is infinitely fast and causality propagates at c then it’s still going to take (distance to the mirror / c) for the fact that you turned on the light to reach the mirror, and that same amount of time for the fact that the light reflected to propagate back to you.


  • vithigar@lemmy.catoScience Memes@mander.xyz8 Minutes
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    2 months ago

    Kind of. The concept of simultaneity breaks down at distances where the speed of light matters. If we base it on what we currently observe and call “now” on the Sun the eight minute old state we currently observe then what does “now” on earth look like from the point of view of the Sun at that same moment? You can’t reconcile a single “now” for observers in both locations.

    An alternative take which is also consistent with observable physics is that the speed of light is infinite but it’s causality itself that propagates at c.

    Thinking in those terms also makes a number of relativistic effects more intuitive. You need infinite energy to reach the speed of light simply because it’s infinitely fast. Time dilates when moving because you’re encountering approaching causality earlier than you otherwise would have. Time “stops” for anything traveling at the speed of light because at infinite speed it just experiences literally everything in its line of travel at once and the concept of “after” becomes meaningless, encountering all future oncoming causality in a single instant.

    This was a bit of a tangent but it’s something that has fascinated me for a long time.



  • I’m all for more people switching to linux, but a lot of your windows issues sound less like windows issues and more like your specific installation is messed up somehow issues.

    One thing I will mention though is that Windows does have native per-application volume control, you don’t need to install EarTrumpet. You can right-click the system tray volume icon and open the mixer, or just search for “volume mixer” in the start menu.




  • A docstring is a comment that is used to annotate types/methods/classes/whatever and can be parsed by the IDE and used to provide various hints/assistance when writing code. Tooltips, parameter type suggestions, intellisense, etc. for things that aren’t native parts of the language all usually come from or can be supplemented by docstrings.

    The specific format of a docstring varies by language, but many of them prefix meaningful tokens with an @, like @type or @param.

    However, if your project is using GitHub it’s also quite common to mention users in comments by prefixing their username with an @, so several vscode GitHub extensions will make any “@{real username}” in a comment into a link to that user, which will show a small user tooltip when hovered.

    Edit: I appear to have conflated docstrings and docblocks, but then so has the initial post. I guess at some point “docstring” has just taken over to colloquially refer to all of it.