Humanity has searched for heaven in the skies for millennia. Interestingly, as science advances, the concept of "sky" changes, but the idea of "the other side" never disappears.
Once we considered the sky a physical ceiling. Then we learned Earth is not the center of the universe. Next, we discovered the solar system is an ordinary dust speck in the galaxy. Now we talk about billions of galaxies. The scale grows, but the ancient question remains: What lies beyond the observable universe?
This question has been revived by American physicist Michael Gillen. He claims heaven is not an abstract fantasy but a physical place located beyond the cosmic horizon of the observable universe.
At first glance, this is a purely metaphysical claim. But it's not just a distance myth.
The observable universe is about 93 billion light-years in diameter. We live within the boundaries of light that can reach us—the rest is no longer "visible reality." This framework is explained by Hubble's law and the concept of the cosmic horizon. The cosmic horizon is the absolute limit beyond which light can never reach us.
Here, at the wall of science, the first serious crack appears. Science, perhaps for the first time, accepts a fundamental truth: Some things exist but can never be observed in principle.
The universe is not just expanding; space itself is stretching. Some regions are moving away from us faster than light, so they have permanently left our information loop. This is no longer mysticism—it's the endpoint of physics.
How does the human mind deal with this concept of "unreachability"? Scenarios about the end of the world have changed throughout history: religious apocalypse, nuclear war, climate collapse, technological失控. All share the same problem: thinking of "the end" as a sudden event.
In 1960, Heinz von Foerster's "exponential growth model" proposed something different. According to his calculations, if human growth continued at the same rate, the system would reach a critical point and collapse in November 2026. The logic was mathematically flawless: finite system + accelerating growth = structural breakdown.
But the model misread reality. Because human behavior and sociology do not behave like stable laboratory elements. Education, global urbanization, and sharp declines in birth rates shifted the system onto a completely different trajectory. The "doomsday point" did not occur, but that doesn't mean the problem disappeared—it just changed form.
Two different fields, same blindness
In space, there are invisible regions—absolute darkness where light never reaches us. On Earth, there are invisible limits—social, demographic, and ecological variables that are noticed too late as the system grows.
In one, physics stops; in the other, human intuition lags. But the result is the same: systems are not infinite—we just read them as if they are.
Gillen's claim of "heaven beyond the cosmic horizon" is not pure science. It's an interpretation—a dangerous thought experiment between physics and metaphysics.
Perhaps that is the key point. Modern cosmology shows that reality does not have to conform to human intuition. Time is not constant, space is warped, and most mass and energy (dark matter and dark energy) are invisible. The majority of the universe is, in principle, inaccessible to us.
Once, rational thought said, "If it's invisible, it doesn't exist." Now, science constructs equations directly based on invisible realities.
The conclusion is harsh for humanity's ego: The more humans know, the less they feel "whole." We go to the moon, map galaxies, split atoms. But the overall picture becomes more fragmented as we approach it. Technology doesn't simplify the universe; it deepens and darkens it.
Our critical mistake is always trying to calculate "the end." But the problem isn't the end itself; it's our method of reading the world. Because reality never behaves according to our linear models.
