• zaphod@sopuli.xyz
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    3 months ago

    Radio waves always propagate at the speed of light, it’s just that the effective speed of light in copper and glass fibre is lower than that in air/vacuum.

    This means that if you have long cables at some distance you’ll get a lower delay by using low earth orbit satellites like Starlink. Assuming a total distance via satellite of 1000km and the effective speed of light in glass fibre to be 2/3 c, cables over 667km will have a higher delay than the satellite.

    • mindbleach
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      3 months ago

      Some fiber-optic cables are faster than others, because they’re full of air. Hollow-core fibers have a large central cutout and/or a close hexagonal packing of smaller glass tubes. The latter are technically a “photonic crystal.”

    • psud@aussie.zone
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      3 months ago

      Speed of light in fiberoptic cable is slower than c for a different reason. The light is in something close to vacuum, signals travel slower than c because the light doesn’t follow a straight path, it zig zags bouncing off the walls.

      A radio wave or laser in reasonable vacuum (in orbit for example) will be lower latency than a signal on a fiber link the same length

      I’m expecting lower ping via starlink than fiber once starlink has laser links between satellites