Visualizing the Number of Humans on the Planet

When I try to comprehend the facts of our world, I frequently feel baffled. The profoundness of living on this Earth with all of its diversity of life, land, inhabitants, people's lifestyles, values, habits, things that happen, things that don't happen, etc... It's incredible and so far beyond my ability to comprehend.

I was recently wondering :

What does the number of humans on the planet look like?

I realized I didn't have the capacity to conceptualize that answer. And so I sent my question to one of my new conceptualization gurus, Chris Jordan. I'd love to share with all of you his generous response in full.

Your question is interesting, because I just recently got to see a profound and moving demonstration of what 6 billion humans look like. It is called the Salt Monument, and it resides in the home of an extraordinary woman named Margot who lives alone in Boulder Colorado. She had an idea something like fifteen years ago to create a living monument containing the number of grains of salt equal to all of the members of the human race. After a long design process that included some engineering, she constructed a huge plexiglass cube in her living room, about seven feet in diameter, and mounted it diagonally onto a burly metal support structure. At the top is an opening into which salt can be poured, and at the bottom is a valve from which salt can be drained. Initially she filled the cube with a number of salt grains (carefully estimated with the use of accurate scales) equal to the then-population of the earth: 4.2 billion people (that was ten years ago). Then, every day, she adds salt at the top equal to the number of people born that day, and she removes salt from the bottom, equal to the number of people who died that day. The whole structure weighs more than a ton.

Along the side of the cube is a scale that shows the progress of time. At the very bottom there is a line that shows the world’s population back around the time of Jesus; it is something like one quart of salt, a few hundred thousand people or so on the whole earth (or maybe it was a few million, but a tiny fraction of today’s population in any event). Then the scale goes up toward the surface of the salt, showing the world’s population increase over time. A whole millennium goes by in between 500 million and 1 billion. Then two billion takes a few centuries. Three billion comes in one century. Four billion comes in a few decades. Five and six billion have come in the last ten years. The exponential growth of our population is astonishingly visible and incredibly frightening.

Every day Margot conducts an elaborate ceremony to mark the passing of 170,000 people, and the birth of 300,000 people. Even if someone dies completely alone and unknown, their passage will be honored by this ceremony— as has everyone who has died in the world in the last ten years. The 170,000 grains of salt taken from the bottom of the monument are dissolved into a large glass jar of water (it is about a teaspoon of salt). The jar stays there for several months, so all of the salt from that time period is dissolved in the jar. The jar then goes in a display cabinet along with the jars from other years. Inside the jar over years, the dissolved salt re-forms into arrays of big clear square crystals that look like miniature versions of the monument.

The salt that Margot adds every day to represent the 300,000 people born gets poured into the top; it is about two teaspoons if I remember correctly. It lands on the surface of the salt below, making a symmetrical cone over time. Each year she flattens the cone out and starts over, so you can see what the year-to-date births look like (a growing cone on the otherwise flat surface, about the size of a large plate of spaghetti when I saw it in October). The one-day old babies are represented at the very top, and the two week-olds are a bigger part of the pile below that, and the 3-month-olds are all in a layer below that, and so on, down to the bottom of the monument, where are the old people are. Each grain of salt will take one human lifetime to pass from the top to the bottom and out.

Around the room she has placed exhibits of different amounts of salt, for scale. There is a black dish with one grain of salt in it; it is the very small kind of salt, where one grain is almost as small as a piece of dust. There is another plate with ten grains, another with 100, another with 3000 (the number of Americans who died on 9/11— much less than the number of people who starved to death elsewhere in the world that same day); the number of people who die from AIDS every year, the number of people worldwide who commit suicide, die in auto accidents, and a few others. These exhibits were mostly about a teaspoon in size, but of course some of the piles where huge compared to one grain.

In juxtaposition, the cube in the middle of the room is astonishing, breathtaking, and incomprehensible. It contains 1900 pounds of salt, equal to the size of several refrigerators. I stood looking closely at it for the longest time, trying to imagine all of the grains of salt that were hidden from view inside the volume of the cube. If I looked very closely, I could make out individual grains of salt right up against the glass, but otherwise it was a sea of whiteness— even a few inches from my face I could not make out individual grains. The amount of grains of salt was far beyond my ability to grasp. I felt like I never even came close to getting my arms around it despite trying pretty hard in a meditative state for more than an hour. I wondered what the Monument would look like if the things inside were marbles instead of salt, and quickly realized that the cube would be something like a hundred yards in size.

Margot has not missed a day in ten years of doing the ceremony. Having lived in a monastic relationship with the Salt Monument for a decade, and holding the meaning of it in her consciousness every day with a spiritual commitment and intention, I believe that she is the person who understands the most of anyone on earth about the enormity of the human race. I wish I could arrange for the Dalai Lama to visit her and see the Monument— I think he would be deeply moved.

Shortly before we left, she brought up another perspective that blew my mind quite the rest of the way. She pointed to the tray that had one grain of salt in it, and said “Imagine that is the sun. In that scale, how far away is the nearest star?” We guessed the other side of the room, or maybe out in the garden. The answer was nine miles. And she said that otherwise, there is absolutely nothing, in all directions. And that is the nearest star; most of the other stars in our galaxy are much further away than that, by up to several magnitudes. We are truly a speck of dust in space.

Then she pointed to the cube, and said that our galaxy has more stars than there are grains of salt in the cube, by a factor of something like fifteen. That fucked me up further—and then she said that there are more galaxies in the universe than there are grains of salt in the cube, by the same factor again. It affirmed for me the incomprehensible scale of our universe, with magnitudes of incomprehensibility; and thus vividly illustrates the enormity of the Mystery. This lovely elegant woman in Boulder just totally kicked my ass.

I turned to her and said “you are trying to deflate my ego, aren’t you?” We had a good laugh. She is adorable, a beautiful and fascinating person. She opens her home to anyone who wants to attend the ceremony and talk with her. I highly recommend it.

And a bit later a second email arrived

Aw jeez, there's a website... Saltmonument.org

I enjoyed reading his description first, feeling as my mind tried to wrap itself around those words and images before entering into the, again, incredibly inspiring website.