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The speed of light can be used in time of flight measurements to measure large distances to extremely high precision. Ole Rømer first demonstrated in 1676 that light does not travel instantaneously by studying the apparent motion of Jupiter's moon Io. Progressively more accurate measurements of its speed came over the following centuries.
The speed at which energy or signals travel down a cable is actually the speed of the electromagnetic wave traveling along (guided by) the cable. I.e., a cable is a form of a waveguide. The propagation of the wave is affected by the interaction with the material(s) in and surrounding the cable, caused by the presence of electric charge carriers ...
Positive lightning is less common than negative lightning and on average makes up less than 5% of all lightning strikes. [ 10 ] A bolt from the blue lightning strike which appears to initiate from the clear, but [ clarification needed ] the turbulent sky above the anvil cloud and drive a bolt of plasma through the cloud directly to the ground.
The Earth is struck by lightning nearly 20 million times each year, and bolts of lightning can travel as much as 10 to 12 miles from a thunderstorm, instantly heating the air to 50,000 degrees ...
But light travels 300,000 km/sec, almost a million times the speed of sound. ... during a thunderstorm does not matter, because lightning can travel along the ...
The jet was initially observed to be traveling up at around 50 km/s (110,000 mph; 180,000 km/h) at a speed similar to typical lightning, increased to 160 and 270 km/s (360,000–600,000 mph; 580,000–970,000 km/h), but then split in two and sped upward with speeds of at least 2,000 km/s (4,500,000 mph; 7,200,000 km/h) to the ionosphere where ...
Faster-than-light (superluminal or supercausal) travel and communication are the conjectural propagation of matter or information faster than the speed of light in vacuum (c). The special theory of relativity implies that only particles with zero rest mass (i.e., photons ) may travel at the speed of light, and that nothing may travel faster.
The most noticeable aspect of lightning and thunder is that the lightning is seen before the thunder is heard. This is a consequence of the speed of light being much greater than the speed of sound. The speed of sound in dry air is approximately 343 m/s (1,130 ft/s) or 1,236 km/h (768 mph) at 20 °C (68 °F; 293 K). [19]