5 ms·

The ending of this makes it sound super clean. 3 ms * speed of light => ~560 miles. "It all makes sense!" But ... isn't the speed of light through fiber actual

by abeppu 6y ago

The ending of this makes it sound super clean. 3 ms * speed of light => ~560 miles. "It all makes sense!" But ... isn't the speed of light through fiber actually like 2/3 of the speed of light in a vacuum? And that fiber isn't going to be laid out in a straight line exactly to the destination. So I think really there must have been a fair bit of uncertainty around that ~3ms to abort a connection.

baby 6y ago
And the time it takes to get to that fiber. It’s a fictive piece probably?
ummonk 6y ago
Was gonna say. Speed of light through cables or fiber optics is roughly 2/3 the speed of light through vacuum. Also I don't see how it would know it has established a connection until the round-trip has happened. All in all, it probably waited more like 10 ms, if this story were true, which it probably isn't.
comex 6y ago
The FAQ addresses this: https://www.ibiblio.org/harris/500milemail-faq.html https://www.ibiblio.org/harris/500milemail-faq.html
- umvi 6y ago
  The FAQ was more entertaining than the actual story!
- frandroid 6y ago
  Since the story has been posted umpteenth times, this is what should be posted these days. Very entertaining, thanks!
  - deleted 6y ago
    [deleted]
  - divbzero 6y ago
    Yes! Thank you GP this too was my first time reading that follow-up FAQ.
- forgingahead 6y ago
  My goodness, the questions people sent in. "I've never met a rich nitpicker" comes to mind.
curiousgal 6y ago
I am surprised that signals travel faster in copper (3c/4) than in fiber (2c/3), anyone has an explanation?
- chongli 6y ago
  The number for copper is not a fixed quantity, it varies with the type of cable. Electric fields are outside of the copper wire, not inside. The copper conductor acts as a wave guide for the electromagnetic wave. So it turns out that things around the cable have an effect on the speed of propagation [1], particularly the insulator. Bare copper wire in a vacuum would be very close to c. In the case of fibre, the issue is index of refraction. [1] https://en.wikipedia.org/wiki/Velocity_factor https://en.wikipedia.org/wiki/Velocity_factor

by abeppu 6y ago

baby 6y ago

And the time it takes to get to that fiber. It’s a fictive piece probably?

ummonk 6y ago

Was gonna say. Speed of light through cables or fiber optics is roughly 2/3 the speed of light through vacuum. Also I don't see how it would know it has established a connection until the round-trip has happened. All in all, it probably waited more like 10 ms, if this story were true, which it probably isn't.

comex 6y ago

The FAQ addresses this: https://www.ibiblio.org/harris/500milemail-faq.html https://www.ibiblio.org/harris/500milemail-faq.html

umvi 6y ago
The FAQ was more entertaining than the actual story!
frandroid 6y ago
Since the story has been posted umpteenth times, this is what should be posted these days. Very entertaining, thanks!
- deleted 6y ago
  [deleted]
- divbzero 6y ago
  Yes! Thank you GP this too was my first time reading that follow-up FAQ.
forgingahead 6y ago
My goodness, the questions people sent in. "I've never met a rich nitpicker" comes to mind.

curiousgal 6y ago

I am surprised that signals travel faster in copper (3c/4) than in fiber (2c/3), anyone has an explanation?

chongli 6y ago
The number for copper is not a fixed quantity, it varies with the type of cable. Electric fields are outside of the copper wire, not inside. The copper conductor acts as a wave guide for the electromagnetic wave. So it turns out that things around the cable have an effect on the speed of propagation [1], particularly the insulator. Bare copper wire in a vacuum would be very close to c. In the case of fibre, the issue is index of refraction. [1] https://en.wikipedia.org/wiki/Velocity_factor https://en.wikipedia.org/wiki/Velocity_factor