Radio waves reach the roof

This is as far as it flies

The request leaves the room as radio waves and reaches the antenna on a nearby rooftop, the cell tower. This is the only part of the trip through the air, just a few hundred meters. The remaining tens of thousands of kilometers run through cables under the ground and under the sea.

Why?Radio waves get weaker the farther they go, and everyone nearby has to share them. So they only travel to the nearest tower. From there, the trip continues by cable.

Learn moreRadio waves cross a few hundred meters in less than a millionth of a second. Even so, this part takes about 4 ms, because the phone waits for its turn and trades signals with the tower. It is like raising your hand in class and waiting for the teacher to call on you. Saying the internet lives "in the cloud" is only a figure of speech.

Time

0.4 ms → 4 ms

Simplified route · light in glass at about 200,000 km per second