Light travels 300,000 km/s.Many communications satellites are in geosynchronous orbit at about 36,000 km above the earth's surface.If you talk to your friend on the other side of the world via a geosynchronous satellite using Skype or your phone,what is the minimum time delay there will be between you and your friend in your conversation?

Question

Quizplus · Accepted Answer

The time delay would be equal to the time it takes for the signal to travel from your device to the satellite (36,000 km away) and then back to your friend's device on the other side of the world (36,000 km away). So the total distance the signal would have to travel is 72,000 km (36,000 km each way). Using the speed of light, the time delay would be:

Distance / Speed = Time Delay
72,000 km / 300,000 km/s = 0.24 seconds

However, the signal would also have to go through some processing and routing on the satellite and ground stations, which would add some additional delay. Taking that into account, a minimum time delay of 24 seconds seems reasonable.

Light Travels 300,000 Km/s