We’re Actually Quite Big

Why do we think we’re so small when we’re actually big?

When contemplating the vastness of the cosmos, humans commonly feel physically miniscule — tiny creatures adrift in the vastness of space. But is this sense of physical inconsequentiality justified on a comparative basis?

Our universe is populated by objects of various sizes. The largest object we’re aware of is the observable universe. Ignoring its continual expansion and the fact it might be part of a much larger universe, astronomers estimate that its current diameter is roughly 10²⁷ meters (92 billion light-years). The smallest object is thought to be the incomprehensibly tiny “string” of energy, estimated as 10^–35 meter in length. Assuming a continuity of object sizes between these extremes, the universe’s size continuum spans 63 orders of magnitude.

On an absolute basis, humans certainly are tiny. But comparatively, the situation differs. Humans are roughly 3 to 7 feet in length, or roughly 10⁰ meter. Humans are 35 orders of magnitude larger than the extreme small end of the size scale, but “only” 27 orders of magnitude smaller than the extreme large end. Surprisingly, the positioning of humans on this continuum is more than halfway to the large end. Employing the powers-of-ten system that scientists use, we are comparatively very large entities! Why are we blissfully unaware of this reality?

We gather information about our comparative size by our sense of sight. We look at ourselves, compare our size to that of objects of various sizes around us, and gain some sense of our relative ranking. But our sense of sight is a limited and biased representation of the underlying physical universe.

Our sense of vision extends from the width of a hair (10^–4 meter) to the distance of the Andromeda Galaxy (10²² meters, or 2.5 million light-years). In other words, the universe “visible” to humans spans 27 orders of magnitude of size. We can thus visualize an impressive 43% (27 of 63) of the orders of magnitude of size in the physical universe.

But such visual efficacy is skewed toward the large end. From the smallest thing we can see (10^–4) to the unseen string at the small end of the size continuum, there are 31 orders of magnitude of sizes. On the large end, there are only five orders of magnitude unseen from the distance of Andromeda to the edge of the observable universe.

In our biased subset of the physical universe, humans are only 4 orders of magnitude larger than the small end, but a robust 22 orders smaller than the large end. In that sense, we are indeed minuscule. We see vastly more of the physical universe larger than our body size, compared with what we see that’s smaller than ourselves.

Humans therefore reasonably, but erroneously, infer from our biased visual limitations that we’re tiny entities adrift in a huge, unending cosmos. This is true on an absolute basis, but not on a comparative basis. Assuming that there is no comparable extension of size at the small end of the continuum, ongoing cosmic expansion insures that at some time in the future, we will indeed be comparatively minuscule creatures. But for now, we are creatures of comparatively consequential size.