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NASA Ping (mander.xyz)

submitted 3 months ago by [email protected] to c/[email protected]

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[–] [email protected] 6 points 3 months ago* (last edited 3 months ago) (2 children)

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.

[–] [email protected] 1 points 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

[–] [email protected] 1 points 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."