Can an Electric Current Travel Instantly Across a 3000000km Long Cable?

Click For Summary
SUMMARY

The discussion centers on the concept of electric current transmission over a hypothetical 3,000,000 km long cable. Participants clarify that while electric signals travel at a significant fraction of the speed of light, they do not travel instantaneously. The current detector would not register an immediate response upon closing the switch at side B; instead, there would be a delay due to the finite speed of signal propagation. This topic is commonly explored in physics forums, highlighting misconceptions about instantaneous communication over vast distances.

PREREQUISITES
  • Understanding of electromagnetic wave propagation
  • Familiarity with the speed of light in a vacuum (approximately 299,792 km/s)
  • Basic knowledge of electrical circuits and current flow
  • Concept of signal delay in transmission lines
NEXT STEPS
  • Research the speed of electrical signals in different mediums
  • Learn about the principles of electromagnetic theory
  • Explore the concept of latency in communication systems
  • Investigate the implications of relativity on signal transmission over astronomical distances
USEFUL FOR

Students of physics, electrical engineers, and anyone interested in the principles of electricity and communication technologies.

salor
Messages
1
Reaction score
0
Hi, all.
There's a thought flashing through my mind yesterday.
Sorry for my lack of knowledge. The thought must be something wrong.
Can anyone correct it? Thanks
If there is a 3000000km long power cable, and the cable is pulled to 3000000km away from the earth.
A power source connected on one side A of the cable on the Earth keeps outputting the electric current, and the switch of side B on the cable (away from Earth 3000000km) is close. And there's a "current detector" on the cable away from side A by 1km. Does the detector detect the current?
At a specific time, if the switch of side B starts to open, does the current start to go from A simultaneously?
If so, people can open and close switch of side B to let people on side A know Morse code .
If the cable is 1LY long, will transmitting message to 1LY away instantly comes true?
 
Physics news on Phys.org

Similar threads

Undergrad Current's Effect on Electrical Arcs
  • · Replies 9 ·
Replies
9
Views
4K
Undergrad Does a Railgun's Current Violate Conservation of Momentum?
  • · Replies 61 ·
3
Replies
61
Views
6K
Undergrad Does current flow back to the power plant through the ground?
  • · Replies 20 ·
Replies
20
Views
16K
Graduate Voltage and current waves in a transmission line
  • · Replies 4 ·
Replies
4
Views
3K
Undergrad How a Battery creates a Potential difference in an electrical current
  • · Replies 14 ·
Replies
14
Views
6K
Graduate Applied physics of current probe / generator clamps
  • · Replies 3 ·
Replies
3
Views
2K
High School Antenna induction, oscillating circuit generating EM Waves
  • · Replies 6 ·
Replies
6
Views
2K
Undergrad Is this example incorrect in Agawal's book on electric circuits?
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad Neutral wire in electric power distribution between substations
  • · Replies 13 ·
Replies
13
Views
4K
Undergrad "Barlow's wheel" used as an electrical generator
  • · Replies 7 ·
Replies
7
Views
2K