Middle RealmIt ain’t what you don’t know that gets you into trouble. It’s what you know for sure that just ain’t so. —credited to Mark Twain (but we ain’t sure if that’s so)
Humans used to believe Earth—and we humans—were at the center of everything. Then we learned that Earth orbits the Sun, which orbits the center of the Milky Way, which just kind of floats weightlessly among a swarm of hundreds of billions of other galaxies connected by a colossal invisible superstructure.
The universe definitely does not revolve around us. We were mistaken.
But here’s the thing about the universe: Size matters. And while we may not reside at the universe’s center, we are in the middle of it—at least in terms of scale.
Our starting realm is the one in which we live—the only realm where life is possible—a place I call the Middle Realm. In terms of scale, the Middle Realm includes everything larger than an atom to the full length and breadth of a galaxy’s arm. I call it the Middle Realm not to be cheeky or to suggest that it is “just right” for life (by volume, practically all of the Middle Realm is uninhabitable), but because humans are in the middle of the largest and smallest known physical distances in the entire observable universe.
The greatest perceptible distance is the size of the observable universe itself, which is 1026 meters across (a 1 followed by 26 zeros). The least perceptible distance is the size of the smallest known physical entity, a subatomic particle called the neutrino, which measures 10–26 meters (a 1 preceded by 25 zeros and a decimal point). By chance, humans are at the scale of 100 meters, slapdab in the middle!
The most critical structures of the Middle Realm are stars and their gigantic nurseries. The most essential building block of the Middle Realm is the humble hydrogen molecule, H2. Neither you nor I would exist without these components.
How are they related, and how do they come together to create things like solar systems and asteroid belts and moons? And how the heck do they produce a planet like Earth, the only planet we know of that is capable of hosting complex, intelligent life? We will answer these questions as we journey from the largest to the most minuscule structures of the Middle Realm, and eventually to us.
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Before we get started, we have to overcome a problem.
Most of us hold incorrect assumptions about how the universe works that can hinder our understanding of the Nine Realms. So, let’s start by deprogramming our minds to overcome what I call normal deceptions. These deceptions aren’t lies told with bad intent; rather, they are misunderstandings we pick up simply by being human. They arise from intuition, language, cultural assumptions, our everyday observations, schoolyard myths, even well-meaning teachers. The kicker? They feel true. That’s what makes them so effective.
These deceptions influence our understanding of how the universe functions. They are not merely trivial errors; they cause us to overlook complexity, misinterpret cause and effect, and mistakenly believe that things are separate when they are, in fact, deeply interconnected. By actively addressing these deceptions, we can enhance our comprehension of the universe and appreciate the intricate relationships that define it.
Before we map the physics of everyday life, let’s pull back the curtain on a few everyday normal deceptions. Not because you need to memorize them, but to show you how deep the rabbit hole goes. Part of this book’s mission is to dismantle these illusions, because only by seeing clearly can we start asking the right questions—like why do we exist?
Let’s begin by looking at a science story everyone knows: Isaac Newton watching an apple fall from a tree. It is a common enough experience—things fall all the time. But Isaac—one of the greatest scientific minds the world has ever seen—had questions: Why does the apple fall? Why does it fall straight down? Why doesn’t it float away? Why doesn’t it go sideways?
Isaac eventually concluded that some invisible, all-encompassing force must be acting on the apple, pulling it straight to the ground and, once settled, keeping it there. He called this force gravity. He further concluded that gravity acted on all objects on the planet—including the apple tree, Isaac himself, his chair, and his quill. He also intuited that gravity is the same force that keeps the Moon orbiting Earth and both of these orbiting the Sun.
This tale has stood the test of time because it is relatable. You don’t need to be a scientist to understand what Isaac was getting at. Our experience of reality—our normal deception—neatly conforms with the fact that things fall (and often break). Releasing an object from some height and observing it travel toward the ground is as commonplace and reliable an earthly phenomenon as the Sun rising. Falling objects and our rising Sun are not strange at all. They are normal. Yet they are both deceptions.
It would be strange if I released an object and it just hovered above the ground. If that happened, how would you react? Shock? Wonder? A pinch of dread? Maybe you’d go into full-on freak-out mode? I probably would. It would mean something is not right.
But here’s the thing: Falling isn’t normal. Not on a cosmic scale. Watching an apple plummet to the ground might feel mundane, but it’s actually weird. The real question is this: Why does it fall at all?
Let’s reframe Newton’s apple moment. Imagine an apple tree floating in deep space. If an apple detaches, it doesn’t fall; it just hangs there, motionless. In most places in the universe, there’s nothing nearby to pull it in. And without a nearby object, the default state is coasting, drifting, doing nothing. If stillness and constancy are the norm, then accelerated motion—the kind that happens to the apple—should be what surprises us.
This brings us to something that trips up many people: orbiting. A satellite circling Earth isn’t flying like a plane; it’s falling. Constantly. But it’s also moving sideways so fast that, as it falls, the ground curves away beneath it at the same rate. That’s what orbiting really is: falling with just enough horizontal motion to keep missing Earth.
Here’s the part people may miss: An orbiting satellite is weightless, just like the people inside. So is everything else that’s falling. That includes Earth, the Moon, the Sun—heck, the entire Milky Way. If you’ve ever wondered, “What does Earth weigh?”—well, it’s in free fall around the Sun, so the answer is nothing. Weight is what you feel when something resists your fall. But when everything is falling together, there’s nothing to push back.
So Chicken Little was right. The sky is falling!
Let’s take another look at Isaac’s falling apple. Our everyday intuition tells us that once the apple is free from its branch, the distance between it and the ground will decrease at an ever-increasing rate. The apple is decreasing its potential energy (a measure of its energy relative to its position to the ground). At the same time, it increases its kinetic energy (a measure of its energy associated with movement as it hurtles toward the ground). We call this falling rate the gravitational acceleration of Earth. Some of you may remember this constant from high school physics—9.8 meters per second squared. But how do you distinguish between the apple falling to the ground and the ground pushing up toward the apple?
This may sound like a ridiculous question. Clearly, our planet isn’t expanding outward to meet all falling objects, from a feather to the Moon. More apparent still, the apple doesn’t sit in place while the ground nudges toward it. Yet, our modern understanding of gravity maintains that the ground does, in fact, accelerate up toward the apple.
Here’s why. About two hundred years after Newton, another genius came along and refined our knowledge of gravity: Albert Einstein. In Einstein’s general theory of relativity—general relativity, or GR for short—gravity is seen not as a force pulling objects down but as the curvature of space-time caused by mass and energy. This leads to a different interpretation of what it means to “fall.”
If that sounds perplexing, don’t worry, I’ll explain space-time in detail in the Cosmological Realm. All you need to know for now is that whenever an object is released anywhere in the universe, it follows a straight path through space-time. We call this path a geodesic. If space-time is curved, as it is near massive objects like Earth, the geodesic appears to us as “falling.” The object isn’t experiencing a force; it’s simply following the most natural, “straight” path through curved space-time.
A somewhat familiar analogue for this geodesic can be found in children’s museums, amusement parks, and science centers worldwide. (Places that always need funding, by the way!) You’ve probably seen one of those coin funnels where you drop a quarter in and it rolls around in an ever-tightening spiral before vanishing into a hole at the bottom. The quarter isn’t actively “seeking” the hole; it’s simply moving along a curved surface shaped by the funnel. Its motion appears circular because of the shape of the surface it’s rolling along.
Copyright © 2026 by Hakeem Oluseyi. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
