Ali Mohammed Redha and Asif Bin Ayub, University of Bahrain, Bahrain
1 Introduction: The Question
One day, as I was driving my car back to my house after a long day at the university. A question popped up in my mind that caught my attention for the whole drive: “Can we feel speed?” Being a physicist, I am used to thinking of questions like this for hours straight. But this, this was different. I began thinking of the topic from multiple perspectives. How would a physicist answer this question? How would a non-physicist answer this question?
Figure 1: Shows a search result of the word “speed” on Pixabay. Can you feel speed from that? Source: Pixabay
The question was so intriguing to me that I decided to resort to the most scientific method of questionnaires, Instagram polls. I asked in the poll, “Can we feel speed?” and 59% of the respondents said YES, the other 41% of course answered NO. What was most interesting about the poll is that physicists following me took both sides. Some said YES while the remaining said NO. I thought the answer would be obvious to physicists, NO is definitely the answer, right? That made me think deeper about the question, particularly about the word feel.
Figure 2: The scientific poll conducted. The question is: “Do we feel speed?” 27 participated with 16 answering YES and the remaining 11 answered NO. The participators are all from Bahrain with various backgrounds and specialties. Source: Self-made.
2 What Do We Mean by “Feel”?
To feel is to experience something emotionally or physically [1]. We can feel emotions: happiness and joy, love and passion, sadness and sorrow – which are abstract constructs of our mind. But the type of “feel”-ing we are interested in is rooted in physical experience: such as touch, heat, and texture. In this physical notion of “feel”, which we might call “sensing”, can we truly sense speed?
We sense our physical surroundings using our five senses: vision, hearing, taste, touch, and smell. Think about them as detectors. Thus, to see if humans can sense speed, we need to see if these senses can detect motion. Imagine yourself driving a car and applying each of your senses separately. Which ones can detect speed?
Figure 3: Shows the senses of a normal human. Us physicists, we do have 6th, 7th, 8th, and 9th senses but we don’t talk about those… Source: Self-made
Identifying speed with vision is no problem. And although speed does not have any sound in and of itself, minuscule collisions, friction, engine sound and other interactions generate sound and can be heard. Combine both visions and hearing together and you get a good motion detection apparatus.
However, take vision and hearing away, and we lose almost all notion of speed. As far as we know, speed cannot be identified by smell or taste – though, it would be interesting to see how an avant-garde chef might imagine the flavor of speed. As for touch, it counterintuitively, cannot sense speed. This is one way that nature tricks us into thinking we are sensing something when we are sensing something else entirely. Our inability to sense speed does not stem from a flaw in the human sensory apparatus, rather, it is a consequence of a fundamental principle of nature.
3 Finally, Some Physics
There is no physical way to distinguish between a moving object at a constant speed and a stationary object. This is known as the (special) principle of relativity and was first theorized by Galileo Galilei in his theory of relativity [2]. Formally, an object/observer that is moving at a constant speed or is stationary is known as an inertial frame of reference. Therefore, according to the (special) principle of relativity, there is no fundamentally preferred inertial frame of reference [2].
To put this simply, this means that everyone has the right to claim themselves to be stationary. Me, I see myself as always stationary so I can claim to be always stationary, “I am the center of the universe”. You, dear reader, always see yourself as stationary and so you have the right to claim that you are always stationary and that you are the center of the universe. No one is wrong here; we are both correct. Someone else might also jump in and claim they are stationary, and we are not, and they will still be right. All of these are physically identical, just seen from different perspectives.
This explains why we cannot sense speed physically by touch. After all, I am always stationary according to myself. There is nothing changing about me, whether I was sitting down, having a walk or driving a car. Everything else around me is moving, but me? No, I am always stationary (keyword: according to me).
What humans physically sense are forces, we feel forces (more accurately, energy transmission). If you hit a wall, then you get hurt by it, because of the force the wall enacts on you. When driving a car, the car vibrates due to friction and minuscule collisions which act as forces on our bodies. Add to that the force exerted by the seat belt and through this nature tricks us into thinking we sense speed when we in fact sense forces. A more in-depth dive regarding our sense of touch is found in [3].
It is important to note that Galileo’s relativity does not give the full picture, and one should resort to Einstein’s relativity for a more accurate representation of reality. Einstein’s relativity agrees with Galileo’s principle of relativity in the case of inertial frames. However, when forces are involved the frames of reference become non-inertial. In that case, there would be preferred frames of reference and that has many implications [4]. Still, how does that answer our question?
4 Conclusion: The Answer
This question goes beyond just science, just answering the question with physics does not feel right. The answer to it is heavily dependent on how we, humans, function. It is always awe-inspiring how complex the human system is. Not just biologically, but socially and psychologically as well. I mentioned how scientifically, we always think of ourselves as being stationary and everything around us to be moving. In the theory of relativity, you are the center of the universe. Go ahead and apply this way of thinking to the social norm and things would be confusing and overly complicated. We sacrifice accuracy for easiness. We pick perceptions and logical systems that would lead us to the simplest, most straightforward path. Everyone is ready to throw away their title of “center of the universe” to live harmonically and in symphony. Ultimately, it does not matter if we believe that we can feel speed or not. What matters is that we can communicate our situation in a way that others would feel. So, is the answer YES, or NO? Well… whatever makes you feel better.
5 Acknowledgement
Many thanks to my friend and colleague Asif Bin Ayub for his help in writing this article. He had a large input and helped me in it throughout.
6 References
[1] Cambridge University Press. Meaning of feel in English [Internet]. Cambridge Dictionary; cited 2023 Apr 27. Available from: https://dictionary.cambridge.org/dictionary/english/feel.
[2] Wikipedia contributors. Principle of relativity [Internet]. Wikipedia, The Free Encyclopedia; 2023 Mar 27, 20:46 UTC [cited 2023 Apr 27]. Available from: https://en.wikipedia.org/wiki/Principle_of_relativity.
[3] Fulkerson M. Touch, Edward. The Stanford Encyclopedia of Philosophy; 2020 June 21 [cited 2023 May 21]. Available from: https://plato.stanford.edu/archives/sum2020/entries/touch/.[4] Wikipedia contributors. Preferred frames [Internet]. Wikipedia, The Free Encyclopedia; 2022 Feb 16, 21:04 UTC [cited 2023 May 21]. Available from: https://en.wikipedia.org/wiki/Preferred_frame.