• i_stole_ur_taco
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    1 month ago

    The problem with geosynchronous orbit is that you need to be at a high altitude to maintain it. That increases the packet round trip time to a receiver on the ground. Starlink satellites orbit low enough to give a theoretical 20ms ping. A geostationary satellite would be at best 500ms. It’s fine for some tasks but lousy for applications that need low latency, like video calling.

      • DesertCreosote@lemm.ee
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        1 month ago

        Unfortunately it’s a hard limit due to the speed of light. Theoretically you could use quantum entanglement to get around it, but then of course you wouldn’t need the satellites anymore.

          • DesertCreosote@lemm.ee
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            1 month ago

            Sorry, I meant theoretically as in “at some distant point in the future where we’ve figured out how to make it work.” I probably read too much science fiction.

            • calcopiritus@lemmy.world
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              1 month ago

              Science fiction quantum entanglement is not the same as real life quantum entanglement. Science fiction has spooky action at a distance, real life doesn’t.

              The speed of light is the speed of causality, the speed of information. It is physically impossible to send information at speeds greater than the speed of light.

            • AnyOldName3@lemmy.world
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              1 month ago

              In real life, all quantum entanglement means is that you can entangle two particles, move them away from each other, and still know that when you measure one, the other will have the opposite value. It’s akin to putting a red ball in one box and a blue ball in another, then muddling them up and posting them to two addresses. When opening one box, you instantly know that because you saw a red ball, the other recipient has a blue one or vice versa, but that’s it. The extra quantum bit is just that the particles still do quantum things as if they’re a maybe-red-maybe-blue superposition until they’re measured. That’s like having a sniffer dog at the post office that flags half of all things with red paint and a quarter of all things with blue paint as needing to be diverted to the police magically redirect three eighths of each colour instead of different amounts of the two colours. The balls didn’t decide which was red and which was blue until the boxes were opened, but the choice always matches.

      • booly@sh.itjust.works
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        1 month ago

        The geosynchronous satellites are about 650 65 times higher than Starlink satellites, so the speed of light is a significant limiting factor.

        Geosynchronous orbit is 35,700 km (3.57 x 10^7 m) above sea level. At that distance, signals moving at the speed of light (3.0 x 10^8 m/s) take about .12 seconds to go that far. So a round trip is about .240 seconds or 240 milliseconds added to the ping.

        Starlink orbits at an altitude of 550 km (5.5 x 10^5 m), where the signal can travel between ground and satellite in about 0.0018 seconds, for 3.6 millisecond round trip. Actual routing and processing of signals, especially relaying between satellites, adds time to the processing.

        But no matter how much better the signal processing can get, the speed of light accounts for about a 200-230 millisecond difference at the difference in altitudes.

        • TrueStoryBob@lemmy.world
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          1 month ago

          Thanks! That’s the shit for which I come to Lemmy. Genuinely, thank you.

          I work in broadcast communications and we use geosync link ups all the time for various shit. I’m pretty sure I know more about satellite communications than a normie, but I’m blind to the intricacies of use case when it comes to stuff like this.

    • freddydunningkruger@lemmy.world
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      1 month ago

      In the past 6 months, Starlink satellites made 50,000 collision avoidance maneuvers. They now maneuver 275 times a day to avoid crashing into other space objects.

      They use an on board AI to calculate the positions, but each time they course-correct, it throws off forecasting accuracy for several days. So a collision isn’t an if, it’s a when, and suddenly we’re in Kessler Syndrome territory. Or maybe enough people will eventually wake up and realize Musk was an actual idiot all along.

      But until then, great, low pings for video calls. Hurray.

      • ayyy@sh.itjust.works
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        1 month ago

        This is completely factually inaccurate. 2 minutes on Google will help you learn but seeing as how you’ve been spewing crap all over this thread I don’t think it’s worth my time to even bother helping you understand.

          • ebc
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            1 month ago

            Shortest answer is that even if all Starlink satellites suddently exploded at the same time for no reason, they’d fall back to Earth in a matter of weeks. They’re waaaay lower than the other satellites you’re thinking of (see discussion on geo-stationary satellites for why), so they need to be actively pushed every few days just to stay up. They’re so low they’re still subject to atmospheric drag.

              • ebc
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                1 month ago

                They’d burn up / vapourize. This is partly why it took them so long to get their space lasers to work (for satellite to satellite communications); these things usually are usually based on a crystal that wouldn’t burn and could hurt someone when the satellite falls.

                  • ebc
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                    1 month ago

                    Man, you really are looking for any excuse to hate on SpaceX, right?

                    If you’re that worried about pollution, just look up the mass of a starlink satellite vs the mass a coal plant burns every hour… Even if the satellite ends up vapourizing as 100% pollution, I’m pretty sure it’s orders of magnitude below other industries like coal power or aviation.

          • ayyy@sh.itjust.works
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            1 month ago

            Search the web for “star link Kessler syndrome”. It’s well documented. It’s also discussed elsewhere in this thread.

          • ayyy@sh.itjust.works
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            1 month ago

            Search the web for “starlink Kessler syndrome”. It’s very well documented. It’s also discussed elsewhere in this thread.