Have you ever wondered why your physics teacher seems to float through the classroom, defying gravity with every step? Well, prepare to have your mind blown because according to quantum physics, they actually are!
In fact, we’re all floating, all the time. Don’t believe me? Buckle up, because we’re about to dive into the weird and wonderful world of atomic interactions that will make you question everything you thought you knew about touch.
When we touch an object, our senses perceive its solidity, texture, temperature and various other characteristics. This sensation isn’t simply contact between our skin and the object itself. It’s actually an interaction between atomic forces at an incredibly small scale.
Every tangible thing in our universe is made up of atoms, which consist of a nucleus surrounded by electrons. Interestingly, there is mostly empty space between these particles.
“If you think about the act of sitting on a chair, what’s happening is that you have your pants and the chair filled with atoms that are mostly empty,” explained Jack Straton, PSU Assistant Professor of Physics. “… [take] a hydrogen atom, for instance, if the nucleus is the size of a big chair, then the electron is living in a realm that’s sort of the distance of Gresham or Hillsboro.”
As you reach out to touch something—like your phone screen or a doorknob—the atoms of your fingers and those of the object engage in a fascinating interplay. As they draw near, a repulsive force comes into play, an electromagnetic force.
When two electrically charged particles approach each other closely—they will exhibit either attraction or repulsion, depending on the charges involved. In the case of touch, it’s all about repulsion.
“What is keeping us from falling through all that emptiness as we try to sit on a chair?” Professor Straton said. “…The electric field turns out to be much stronger than the gravitational field. It’s actually the electrical repulsion of the atoms in the chair and the atoms in your pants shoving against each other that keeps you from falling through… we’re literally floating on electrical fields.”
Another reason atoms cannot physically touch is Pauli’s Exclusion Principle. This principle states that two or more quantum particles cannot occupy the same space.
So, if we’re not actually touching anything, why does it feel like we are? The answer lies in our remarkable brain.
Drake Mitchell, Professor and Chair of Physics at Portland State University, offered a straightforward explanation.
“We’re experiencing it because we got a nerve impulse,” Mitchell said. “A brain doesn’t know anything except what gets sent to it. The trick has to happen on the outside. Once it’s a nerve impulse, your brain’s set up to deal with it. You know, we’re going to say, ‘Ooh, that’s hot. I better let go of it.’”
Essentially, what we perceive as touch is not truly the connection of matter, but rather how our brain comprehends the interaction of electromagnetic fields.
The interaction between atoms encompasses more than just electron repulsion. There are other factors that contribute to our sense of touch, such as chemical bonding.
Chemical bonds allow electrons to attach to imperfections on the surface of objects, creating friction. This friction is an aspect of our perception of touch. It makes groups of particles tangible and enables us to interact with our surroundings.
Professor Mitchell provided an insightful analogy to explain friction and slippery surfaces.
“Even though atoms aren’t directly touching each other, what we perceive as touch is actually the interaction of electrons at the outermost surface of atoms,” Mitchell said.
“…Consider the atoms in a metal: the nuclei are relatively stationary, not jumping around,” Mitchell explained. “There’s some minor vibration due to thermal energy, but overall, the nuclei maintain fixed positions… As a result, there’s a periodicity to the electron clouds surrounding these nuclei, creating a consistent surface at the atomic level.”
To add another layer of complexity to our understanding of touch, let’s consider the quantum nature of electrons. These tiny particles exhibit a characteristic called particle-wave duality, meaning they can behave both as particles and waves. They can be present in multiple places simultaneously and even interfere with themselves.
“We can’t say that the electron is a particle going through Gresham and Battleground and Hillsboro… and back to Gresham,” Professor Straton said. “…It doesn’t work like a planet… if I’m sitting in [a chair]… the electron can sometimes be dancing on my nose right here, and it can also be dancing on the tip of Mount Hood… it travels not as a particle around the atom, but… as a wave… of probability.”
Because of electron wave packets overlapping each other, it can appear as if objects are being touched when their atoms never truly come into contact.
“Since these electrons are in a vague cloud, sometimes dancing on my nose, sometimes on the tip of Mount Hood,” Professor Straton said. “…there’s a finite probability that the electron that I think is mine, is actually jumping over and landing on a person next to me. And their electrons are jumping over and landing in an atom in me. That’s a very small probability, but it’s not zero. … we don’t touch people, and our electrons can be shared with other people.”
Philosophers and scientists have long debated the question of existence and our interaction with the world around us. Various theories—such as the concept of the Middle Way or the Boltzmann Brain theory—attempt to explain our existence by suggesting that it may not be as straightforward as it seems.
In the grand scheme of things, understanding touch reminds us humbly of our limited perspective and the vast universe that extends far beyond it. It encourages us to question, explore and genuinely appreciate the fabric of existence in which we participate.
Professor Straton leaves us with a final thought.
“One other paradox is that even though we don’t touch the world around us, it is in no sense entirely separate from us,” Professor Straton said. “That is, as we attempt to walk across a carpet by pushing our foot backwards, it is the responsive force provided by the carpet that moves our foot forwards (of course transferred to us through changing electrical fields).”
“…So, while we don’t touch the world, we are simultaneously dependent on the service the world offers us to move through it. So instead of a nihilistic response to the information that we don’t touch the world around us, we should always bless the world for its many kindnesses to us.”
The next time you’re sitting in class, remember that you’re not actually sitting on the chair—you’re hovering ever so slightly above it.
This mind-bending reality doesn’t make our experiences any less real or meaningful. If anything, it adds a layer of wonder to our everyday interactions. We’re not just living in the world—we’re constantly engaged in a complex dance of particles and forces that allow us to perceive and interact with our environment.
So the next time someone tells you to “get in touch with reality,” you can smile, knowing that you’re always just a little bit out of touch—and that’s exactly how the universe wants it to be.
