Can We Outspeed the Impossible?
As people drive to work every day, they must obey the rules of the road. A speed limit dictates how fast a car can go on a particular road. Albert Einstein believed that everything in the universe had a speed limit as well: the speed of light. However, many science fiction movies and television shows break this intergalactic law. For example, the Millennium Falcon from Star Wars was said to have reached a speed of one and a half times the speed of light through the fictional dimension of hyperspace (5). Is achieving faster-than-light speed (FTL) possible in reality, and if not, why?
Trying to outrun the speed of light differs from outrunning anything else because of Albert Einstein’s famous Theory of Relativity: energy = mass * speed of light2. This equation states that mass is directly related to energy and that the faster an object moves, the more kinetic energy it has. Therefore, the faster an object moves, the more massive it becomes (2). This is true for any object, but the difference in mass between a moving tennis ball and a stationary one is negligible since the effect is so small. As an object’s speed approaches the speed of light, however, its mass skyrockets to infinity. Since more massive objects require more energy to move, it would theoretically take an infinite amount of energy to surpass the speed of light. Based on our current understanding of physics, humans cannot reach the speed of light because there is no way to accelerate a person to such speeds (3). Is there another way, though?
The field of quantum mechanics provides some interesting theories regarding FTL. One of these concepts is the “Alcubierre Drive,” which involves bending space-time, the fabric that merges the dimensions of time and space, into a sort of bubble around a spacecraft. The idea is that the space-time in front of the object contracts while the space-time behind it expands (6), creating a separate region of space-time that the spacecraft rides along in, bypassing the regular limits as the ship itself is not moving within this region. This is very similar to fictional hyperspace (6). Astrophysicists also talk about theoretical “wormholes” that can open shortcuts through space-time to send an object to its destination faster than light can travel to it (3). Unfortunately, neither of these theories completely agrees with our current understanding of physics. They push past the limits in some way, with either negative mass/energy or manipulation of space-time, leading to paradoxes in time travel. The unfortunate truth is that there isn’t a way to achieve FTL speed, even after delving into the incredibly confusing realm of quantum mechanics.
In reality, however, you can actually bypass this system in your own home. Consider this: if you use a light source and your finger to project a shadow and then move your finger, the shadow actually moves faster than your finger, especially if you do it at an angle (4). The distance between the light and the object dictates the speed of the shadow, regardless of how long it takes light to cover that distance. While a shadow isn’t a physical object – it’s actually an optical illusion – it’s fun to think that in order to bypass the universal speed limit, you don’t need futuristic starship engines, hyperspace tunnels, or telepathic communication abilities. All you need is a flashlight and your own finger. As author Terry Pratchett once said: “Light thinks it travels faster than anything but it is wrong. No matter how fast light travels, it finds the darkness has always got there first, and is waiting for it” (7).
Bibliography:
- Cosmic Speed Limit. American Museum of Natural History. Retrieved from https://www.amnh.org/exhibitions/einstein/light/cosmic-speed-limit#:~:text=Nothing%20can%20travel%20faster%20than,of%20energy%20to%20do%20so.
- Sutter, P. (2023, 2 23). Will Humans Ever Go Faster Than Light? Discover Magazine. Retrieved from https://www.discovermagazine.com/the-sciences/will-humans-ever-go-faster-than-light
- Phelan, J. (2022, 4 25). Can anything travel faster than the speed of light? Live Science. Retrieved from https://www.livescience.com/can-anything-travel-faster-speed-of-light
- Gibbs, P. (1998). Faster Than Light. University of California. Retrieved from https://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/FTL.html
- Lough, C. (2014, 12 8). How Fast is the Millenium Falcon? A Thought Experiment. Reactor. Retrieved from https://reactormag.com/star-wars-how-fast-is-the-millennium-falcon/
- Williams, M. (2017, 1 20). What is the Alcubierre “warp” drive? Phys.org. Retrieved from https://phys.org/news/2017-01-alcubierre-warp.html
- (n.d). goodreads. Retrieved from https://www.goodreads.com/quotes/tag/speed-of-light
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