Which Is Larger, The Human Brain or the Universe?

Which is Larger—The Universe or Your Brain?
I imagine the look on your face when you read the title question was the same as the look of the typical person in medieval  times to the assertion that the earth was round. It's obvious, is it not, that the human brain is smaller than the universe. Well, maybe not. Perhaps it depends on how you measure the human brain and the universe.
The measurement issue may be illustrated with a balloon. Suppose we have an non-inflated balloon. How big is the non-inflated balloon? Squeezed into a ball, it has perhaps a diameter of 3" and a spherical  volume of about .061 gallons. Now let's inflate the balloon to a spherical diameter of 5 feet. The balloon now has a spherical  volume of about 489.60 gallons. What is the correct size for the balloon, .061 gallons or 489.60 gallons? If I say 489.601 gallons, you would properly protest that my preferred measure is comprised of very little balloon and a great deal of (mostly) empty space. But that "inflated balloon" answer is the one most humans use when we compare the human brain and the universe.
You may question whether the universe is as empty as my simplistic balloon example suggests. We are told of all the galaxies and other heavenly bodies that the universe contains and imagine a very crowded universe. We are not told of the vast empty spaces out there. Adam Hadhazy, is an exception. In his article in Discover Magazine, December 2016, "Nothing Really Matters", pp. 46-53, Hadhazy contends," 'space' is certainly an apt nickname for our cosmos, since there's a heckuva lot of it out there." He illustrates the emptiness of our cosmos with the following examples: 
Between here and the moon, about a quarter-million miles away, there's virtually nothing—just stray hydrogen, helium and the odd dust particle. On far grander scales, this barrenness becomes unimaginably vast. A desolate, virtually starless, 2.5 million light-year gulf—- that's nearly 15 quintillion miles— separates our home galaxy, the Milky Way, from its nearest sizable neighbor, the Andromeda Galaxy.
How do we deal with the measurement problem that arises when we try to measure something like our universe that consists mostly of empty space. Perhaps we have to consider measurement units other than the ones we now use for length, mass, time and temperature. Interestingly, the answer may lie with a proposal by Max Planck in 1899.
 Max Planck, among other scientists of his day, recognized that measures of time and space chosen by human beings were unlikely to retain their significance for all times and for all environments, terrestrial and human or otherwise. Planck proposed that natural units of mass, length, and time be constructed from fundamental constants of nature: the gravitation constant G, the speed of light c, and the constant of action, h, which now bears Planck's name. (Planck's constant determines the smallest amount by which energy can be changed—the 'quantum'). [1]
Using these universally suitable measures of time and space, which is larger, the universe or our brain? It is not even close: the human brain is vastly larger than the universe.
The human brain gains it size from its complexity which, in turn, arises because the human brain is alive—living things are incredibly complex. For example, the number of different possible thoughts or ideas—the  number  of  different electrical patterns—that a human brain can have is I0 to the power of 70000000000. This dwarfs the number of atoms in the observable universe—a mere 10 to the power of 80.[2}
Our brains have little difficulty containing our universes. And they do precisely this. My book contends that each of us creates within our brains, within predetermined constraints, the universe in which we exist. [3}
Does it matter? Is it helpful to know that each of us creates  our own universe? The answer is a resounding yes. We are able, for example, to see clearly for the first time the relationships among  time, gravity, and inertia and thus to understand fully why people who live at high elevations and those riding in supersonic aircraft will age (slightly) less rapidly than other persons. This is just one among many examples of ways we will see our world differently when we realize that we each create our universe within our brains.

Notes
1. See the excellent book by John D. Barrow, The Constants of Nature: From Alpha to Omega—the Numbers That Encode the Deepest Secrets of the Universe (New York, NY: Pantheon Books, 2002), 24-25. See also pages 54-55 and 117-118.
2. Barrow, pp. 117-118.
3. Donald W. Jarrell, At the Edge of Time: Reality, Time, and Meaning in a Virtual Everyday World (North Charleston, SC: CreateSpace Independent Publishing Platform, 2012, 2014.)