How fast can a signal go from Bogotá to Jakarta?
No faster than 66.04 ms one way and 132.09 ms there and back. That is light in a vacuum along the 19,799 km great circle between the two cities. Optical fibre slows light by its group index, 1.4682, so through glass the same round trip takes at least 193.93 ms.
| Medium | One way | Round trip |
|---|---|---|
| Light in a vacuum | 66.04 ms | 132.09 ms |
| Light in glass, group index 1.4682 | 96.97 ms | 193.93 ms |
| Great-circle distance, WGS84 | 19,799 km | |
What does a real line add?
Cables leave the great circle, and every router and queue on the way adds time, so a measured round trip from Bogotá to Jakarta lands above 193.93 ms whenever the whole path is glass. A line that only just reaches 193.93 ms runs at 68.1 % of light, the most fibre allows.
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How are these floors computed?
The distance is Lambert's formula on the WGS84 ellipsoid between the population-weighted centres UN DESA gives for the two cities in World Urbanization Prospects 2025, checked against GeographicLib to within 100 m on ten pairs. Light covers 299,792.458 km each second. The glass figure uses Corning's group index for SMF-28e+ fibre at 1550 nm, 1.4682.