A man by the name Albert Einstein loads a tram-car on the way home from work. The scientist sits in his seat as it rolls away from the station, watching a tower clock turn. He moves farther and farther away, his eyes still fixed on the clock. He theorizes that if he were to recede from the clock tower at the speed of light, then the hands would appear to freeze. However, he knew that back at the cite of the tower the hands would proceed to turn. This theory was time-dilation, the idea that the faster you travel through space, the slower you pass through time. This theory stems from Einstein’s published theory of relativity in 1905, and of general relativity in 1915.
Stemming from this idea, I have always been fascinated by the rules of time and space, how different elements can create different effects and how it affects me. Every other week when pounded by existential crisis, I fall into a deep hole in youtube where I nearly break my brain trying to understand genius’ theories. My “recommended” bar is full of astrophysicist Neil Degrasse Tyson, media based educator VSauce, and a questionable source called RealLifeLore that explores different theories such as “What If We Drained the Sea?”
While these videos are fun to watch, I can’t help but circle back to the terms theory of special and general relativity, spacetime, and time-dilation. These terms are all very relative to each other, and intersect with their effects on the universe.
To begin understanding Einstein’s theory of time-dilation, we have to know certain vocabulary that affect it. He discovered that unlike Isaac Newton’s ideas that space, time, and gravity were separate equations and affects, they would rather become relative to each other and form dimensions. Time, a one dimensional field, and space, a three dimensional field fuse together to create the 4D continuum of spacetime. Involving spacetime, the equation E=mc^2 created by Einstein suggests that energy and mass are relative and interchangeable which create a basic understanding of his theory of special relativity.
The term time-dilation fits into special relativity. The formula (E=mc^2) along with formulas discovered by both scientists James P. Maxwell and Isaac Newton helped form Einstein’s theory. According to this theory, he predicted that the spacetime around a specific mass can be warped and twisted under this massive energy. Most importantly, it states that the speed of light (while constant) can appear different to individuals traveling at different speeds. This is where the term “relativity” comes to play.
Time-dilation: Gravity affects time.
Imagine two clocks, one on earth and one on the International Space Station. If you were to shine a flashlight from Earth, the clock on the Space Station would measure the speed of light of this flashlight faster than the one on earth.
How is this possible? Well, light always travels at the speed of light (299 792 458 m / s), so the only possible way for light to lose energy as it travels farther from the origin is for the wavelength to stretch out. For the sake of this analogy, we will simplify the speed of light down to 1 foot per nanosecond. As the light waves travel farther away from the origin, it loses energy. If the clock on Earth near the flashlight measures on foot per nanosecond, then by the time it reaches the Space Station, the wavelength has been stretched out three times the original length. If the clock must tick on Earth the same frequency as the clock in space, then the clock in space has to tick 3 feet per nanosecond. This results in the Earth clock still ticking one foot per nanosecond, and the space clock three feet per nanosecond. Therefore, the gravity of a mass is actively affecting the frequencies of light wavelengths all around itself, essentially bending spacetime.
Have you ever stood outside and looked at the sky, thinking about how you are just standing on a rock? Craned your neck to look up straight above you into stars? Next time you are outside at night, think about the energy that passes from one mass to another and the energy that passes through you. Know that you are a part of this universe, and the laws such as special relativity need you to function as well. While this subject is hard to wrap your head around, I urge readers to do your own research on the topic and find something that interests you. Space exploration is a field that needs contribution from younger generations, and just educating yourself is taking a step in the right direction.