By Jonny Lupsha, Current Events Writer
The speed of light is matter’s fastest speed, but maybe humankind can cheat it. A new scientific theory notes that spacetime itself moves faster than light, so bending a bubble of space around a ship could work. The Cherenkov Effect is a fascinating exception.
Einstein’s studies suggested that it would be impossible to travel faster than the speed of light, which is approximately 186,000 miles per second. This sort of “universal speed limit” makes it difficult for humankind to reach other star systems. With current technology, rockets would take more than 50,000 years to reach Proxima Centauri.
What if the ship weren’t the only thing moving? Spacetime itself can move more quickly than light; in fact it’s believed that the universe is expanding at a far faster pace than light can travel. Scientists have suggested recently that it may be possible to create a density of energy lower than the emptiness of space, therefore bending a bubble of space around an object for travel.
In his video series Understanding the Misconceptions of Science, Dr. Don Lincoln, Senior Scientist at Fermi National Accelerator Laboratory, discussed an observable aspect of faster-than-light travel called The Cherenkov Effect.
A Promising Student
“While it’s impossible to go faster than light in a vacuum, it’s actually pretty easy for objects to go faster than light through something like glass,” Dr. Lincoln said. “And you want to know how we know about this? When this happens, it makes glass glow a lovely blue color.”
According to Dr. Lincoln, this blue light was discovered in the 1930s by Russian physics student Pavel Cherenkov. Cherenkov noticed that when uranium salts dissolved in sulfuric acid, the solution glowed. At the time, it was believed that the glow was caused by radiation, but Cherenkov isolated the sulfuric acid in a test tube and held it near a radioactive material, which reproduced the effect.
“Cherenkov eventually was able to show that even water would glow in the presence of a lot of radiation,” Dr. Lincoln said. “He shared his work with Sergey Vavilov, who was his thesis advisor; Vavilov mentioned the effect to Igor Tamm and Ilya Frank, who figured out what was going on.
Cones of Sound, Circles of Light
Dr. Lincoln said that in order to understand how objects travel faster than light through glass, we should consider the sonic boom. As planes fly, they compress the air in front of them, the energy of which moves away at the speed of sound. As a plane approaches the speed of sound, it travels as fast as the compressed air in front of it. At the speed of sound, compressed air stacks up in front of the plane.
“If the plane moves faster than sound, the sound waves don’t stack up like they did when the plane was moving at the speed of sound, but instead what happens is that each location, the plane makes sound from pushing the air out of the way, and that sound leaves the location at which it was made, traveling in all directions at the speed of sound,” he said.
“It makes a series of circles appearing at each point the plane passes. The circles add up and make a cone of sound that surrounds the path of the plane.”
Cherenkov light is the same idea, but it occurs when a charged particle passes through a transparent material at speeds faster than light passes through the material. According to Dr. Lincoln, the electric charge of those particles jiggle the molecules of the material, which give off light as they move. The light travels outward in a circular pattern at the speed of light.
Cherenkov light shows how materials pass through objects like glass faster than light. While sending matter through space in a vacuum faster than the speed of light has yet to happen, scientists hope that bending spacetime around a ship could hint at a solution.