In certain science fiction or speculative works, there are instances where the concept of light traveling slower than its usual speed in a vacuum (299,792,458 meters per second) is explored. However, it's important to note that this is purely a fictional concept and not based on our current understanding of physics. Here are a few examples of media where the idea of slower-than-light speed for light has been portrayed:
"Anathem" by Neal Stephenson: In this science fiction novel, the author introduces the concept of "Slines" (slow lines) where the speed of light is significantly slower compared to the normal speed. It is a key element of the book's fictional universe.
"The Algebraist" by Iain M. Banks: This science fiction novel takes place in a universe where the speed of light is not constant and can vary in different regions. It explores a range of slower-than-light speeds for light.
"Einstein's Bridge" by John Cramer: In this novel, a hypothetical device called an "Einstein-Rosen Bridge" is used to slow down light so that communication can occur between parallel universes.
"Star Trek" series: While not explicitly about light, the concept of "subspace" is often depicted in the "Star Trek" franchise, where signals and communications can travel faster than the speed of light, allowing for interstellar communication.
It's important to reiterate that these depictions are purely fictional and not supported by our current understanding of physics. In reality, the speed of light in a vacuum is considered a fundamental constant of nature.