By The Motley Advocate
If you haven’t already guessed, I am a huge fan of The CW’s show The Flash. At the end of season 2 Barry Allen traveled back in time to save his mother from being murdered by the time traveler known as the Reverse Flash. This action changed his history, creating a new reality. In the world of comics, this event, referred to as Flashpoint, had far reaching actions for the entire planet.
In the season 3 premiere, and in the comics, to fix the world of Flashpoint, Barry traveled back in time again, and allowed the Reverse Flash to kill his mother. Hypothetically, this should have restored the original timeline as Barry undid the one change he made to the time stream. However, when Barry returned to the future he found that there are a few new changes to the original timeline. Based on the previews, dealing with the changes he has caused through time travel will be a big part of season 3.
So let’s talk about the science in the season premiere. The idea of changing one event in the past with drastic consequences in the future is often called the butterfly effect. You may be familiar with it from the film starring Ashton Kutcher or the short story A Sound of Thunder by Ray Bradbury. However, while it is a popular idea in science fiction, it is in fact a real concept in the subject of chaos theory. Science fiction fans may remember chaos theory from the movie Jurassic Park.
Without going into too much detail, chaos theory, also known as deterministic chaos, argues that unpredictable, seemingly random, events are still caused by underlying predictable laws. For instance, when a player hits a baseball with a bat, we cannot predict exactly where it will land. However, we know that this is controlled by physical laws such as gravity, collision against the bat, and wind resistance as the ball travels in the air. The term butterfly effect was coined by Edward Lorenz, thought to be one of the first experimenters of chaos theory, while he was running computer simulations to predict weather patterns. During this experiment, Dr. Lorenz wanted to repeat a previous simulation not from the beginning but from a mid-point, and entered the numbers in manually. By doing so he rounded one number to .506 from .506127. You would think that a change this small would produce similar results, yet the two simulations had very different results because of this small change. This happy accident led to the idea known as sensitive dependence on initial conditions. Basically, even the smallest change in the initial conditions can make unpredictable changes in the results. It’s called the butterfly effect because one famous metaphor states that a butterfly flapping its wings in just the right place, at just the right time, can influence a hurricane on the other side of the world. Fun fact: Lorenz originally used the flapping of a seagull as an example before changing to the butterfly.
It is important to remember that the butterfly effect is not focused on what we can predict, but what we cannot predict. As this Boston Globe article discusses, if something as small as the wings of a butterfly can influence when a tornado will happen, humans will never be able to predict exactly where a tornado will occur. We can guess when a tornado might occur, based on the conditions we know, but without the remaining data, we will never be 100% right.
Alternatively, we need to accept that there are some conditions we can not control. When something random happens in life, we often try to identify the single butterfly that caused it to happen. However, there is actually a swarm of butterflies, making it impossible to find the single, correct one. At the end of the day, chaos theory suggests that what seems random could actually be perfectly predictable. It is just impossible for humans to account for every possible factor that will have an effect, and thus the results are unpredictable.
Chaos theory played a significant role in the premiere episode of season 3 of The Flash. One change to the time stream had numerous unpredictable changes to Barry Allen’s world, including the introduction of Kid Flash. The big difference is that unlike real chaos theory, Barry knew exactly what that variable was, considering he caused it. However, when Barry went back in time to restore the original timeline he fell victim to sensitive dependence on initial conditions. Even though his mom was still murdered it did not happen 100% exactly as before, and as a result his world is still different. How will Barry handle the changes? I guess we’ll just have to watch and find out. In the meantime, check out this awesome PSA where the cast of The Flash supports STEM education.