How many things are There!?

Hey, Vsauce. Michael here. Imagine if we gathered every single human alive today and threw them into the Grand Canyon. The result would be a fascinating yet sobering sight. The Grand Canyon, a colossal natural wonder, wouldn’t even be remotely filled by all 7.159 billion of us. We would form only a modest pile, a mere fraction of the Canyon’s vast expanse. This visualization not only offers a stark perspective on humanity's physical scale relative to the natural world but also prompts a deeper reflection on the nature of "things" and our place within the universe.

Now, let's delve into another intriguing perspective: the sheer quantity of saliva you produce throughout your lifetime. On a daily basis, you generate about one to two liters of spit. Accumulated over a lifetime, this amount is insufficient to fill an Olympic-sized swimming pool. It’s a peculiar but vivid way to grasp the limits of our biological outputs compared to the grand scale of physical objects and spaces.

Speaking of scale, consider Lego bricks. To date, a staggering 560 billion Lego parts have been manufactured. Compare that to the estimated number of grains of sand on Earth, which is about 7.5 x 10^18. These numbers, though mind-boggling, barely scratch the surface of the broader question: How many things are there in total?

Let's tackle this by defining what constitutes a "thing." For simplicity, let’s say something is a "thing" if you can think about it or talk about it. This includes everything from tangible objects to abstract ideas. In this context, "things" encompass everything from the physical and the imaginary to the impossible and the conceptual. Even the act of making a video about how many things exist is, in itself, a thing.

When we attempt to quantify the number of physical things in the universe, we encounter some fundamental challenges. The observable universe, which is the portion we can currently see and measure, has a future visibility limit estimated at about 62 billion light-years in any direction. Within this observable universe, there are roughly 10^80 elementary particles. These particles are the smallest units of matter we currently know of, with no further internal structure. Thus, the physical universe could be summarized in terms of these particles. Each physical object, be it a water molecule, a dog, or a planet, is simply a particular arrangement of these fundamental particles.

But what if future discoveries reveal that what we currently call elementary particles are actually made up of even smaller entities? To account for this possibility, we might consider the maximum number of the smallest measurable units, like a Planck volume. A Planck volume is incredibly tiny, and theoretically, 10^183 such volumes could fit within our observable universe. This number, 10^183, provides a high estimate for the smallest physical things.

However, imagination stretches beyond physical measurements. While the smallest physical things we can measure have limits, the realm of imagination appears boundless. The number of possible thoughts, ideas, and concepts seems infinite. For instance, there is no limit to how large a number we can conceive. Unlike physical things, which exist regardless of human perception, abstract thoughts exist only when they are conceived or expressed.

To gauge the limit of thoughts within our universe, let’s consider the following hypothetical scenario: We convert the total mass of the observable universe into a super-powerful computational machine. This machine, operating at the theoretical maximum speed allowed by the laws of physics, could process information at a rate of 1.36 x 10^50 bits per second per kilogram. With an estimated total mass of 3.4 x 10^50 kilograms for the observable universe, this machine could process 4.624 x 10^110 bits per second.

Given the universe’s lifespan until the heat death, approximately 10^16 seconds, and assuming an average thought requires about 800 bits to describe, we can estimate the total number of thoughts possible: 1.458 x 10^227. This number dwarfs the count of physical things. It illustrates that the number of possible thoughts and imaginings vastly exceeds the count of physical objects.

In essence, when combining the vast numbers of physical things with the boundless potential for thought and imagination, the latter overwhelmingly dominates. This highlights a profound truth: In the grand scheme of the universe, it truly is the thought that counts. Thanks for joining me on this cosmic exploration of scale, thought, and existence. As always, thanks for watching.