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Cake day: September 27th, 2023

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  • ilinamorato@lemmy.worldtoScience Memes@mander.xyzLaunches
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    5 days ago

    Yeah, orbital mechanics gets a little bit mind-bendy sometimes. If you’re in a stable circular orbit, accelerating in the direction you’re traveling will actually result in you traveling more slowly because you have moved to a higher orbit, and firing engines to slow down will actually speed you up because you move in closer to the host body and take up a faster orbit.

    This is actually a problem spacecraft deal with regularly. If a Dragon capsule is behind the ISS and wants to dock, using its thrusters to accelerate toward the ISS will actually result in it falling further behind. Decelerating will get it closer, though it will then be in a lower orbit. Orbital rendezvous is tough.



  • ilinamorato@lemmy.worldtoScience Memes@mander.xyzLaunches
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    6 days ago

    Good question, but if you cancel out only a little bit of orbital velocity, you just orbit in a little bit closer. Without any appreciable drag acting on you, there’s nothing that will keep your orbit decaying. You’ll just be in a smaller, perhaps slightly more eccentric orbit.



  • ilinamorato@lemmy.worldtoScience Memes@mander.xyzLaunches
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    6 days ago

    Because the Earth is really cookin’, and anything anyone you hurl toward the sun will inherit that orbital velocity as well, meaning that they’ll actually end up going around the sun, instead of into it. And due to the speed it would pick up on its way in, it would basically take up a highly-eccentric yet stable elliptical orbit.

    “Well, what if we throw them in the other direction, to make up for it?” That’s called retrograde, and that’s basically exactly what you’d have to do: cancel out the Earth’s entire orbital velocity. Which would take a lot of energy, plus a couple of really exacting gravity assists from planets on the way in.

    (Edit to add: I may have explained this poorly. Basically, if you don’t change your orbital speed at all, any movement you make toward or away from the host body means you just end up in an orbit of the same average distance, but in a more eccentric [elliptical] shape.)

    By contrast, even though the escape velocity from the solar system is no slouch (42 km/s), you get to start with the Earth’s orbital velocity (30 km/s)–meaning you’re already a little under 3/4 of the way there. Plus, if you can make it to Jupiter and Saturn, you can get a significant gravity assist, and they’re much bigger targets for such a maneuver than Mercury or Venus are.

    So, yeah, bottom line: you only need a delta-V of about 12 km/s to get out of the solar system, but a delta-V of 30 km/s to get to the sun without going into orbit.





  • “Storage management is expensive”

    It’s really not, though.

    //////

    ETA: I stick by my premise and my conclusion (storage management isn’t expensive, and it’s probably a Nitro thing), but my math may be wrong and my usage is apparently not normative. The costs are probably not so negligible, but I would still assume they aren’t as low as they want us to think.

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    Discord has 200,000,000 MAU. If every single one of them uploaded a file every month (of pretty much any size) and Discord tossed it into an AWS S3 IA bucket, it would cost them $500 to store that data. Their total S3 bill for storage would be five hundred US dollars. Storage is dirt cheap. AWS doesn’t even charge per gigabyte on that storage type, it’s so cheap; they charge for downloads.

    So, ok. Let’s talk downloads. If each of those files were 25GB and downloaded twice (probably an underestimate, but not everyone is uploading files, so I’m going to make the completely unfounded assumption that it’ll all shake out), it would cost them a couple hundred thousand dollars. Which, ok, that’s much more significant than $500. But Discord made $575 million last year—so the S3 download costs would be 0.03% of their total revenue. They probably spend 2-3 times more on coffee.

    Storage management is emphatically not expensive.

    My guess? They just saw that the higher upload limit was eating into their Nitro subscriptions.









  • I just installed Linux Mint on a 15-year-old desktop that has never been upgraded and was middle-of-the-road when I got it. It shipped with Windows 7, and I tried a couple of times to upgrade to 10 (it failed every time, either losing core hardware functionality, running so slowly as to be unusable, or just refusing to boot altogether). But it runs Linux like a dream. Seriously—it’s easily running the latest version of Mint better than it ran an 11-year-old service pack of Windows 7.

    What’s even crazier is that I installed VirtualBox on it, and put Windows 10 on that, to use some work programs. And that runs Windows 10 a bit slowly, but otherwise more or less flawlessly!

    That’s right: I’m having a better Windows experience in Linux than I’ve ever had on baremetal Windows on this box.

    I can’t believe I didn’t do this…well, 15 years ago.