Planets and Population

The planet Mars is a very advanced planet: it’s entirely populated by robots. People haven’t set foot on Mars but that may change in the next 15 years or so.

The only extraterrestrial body that people have visited is the moon. And on their way to the moon, they got to see the entire earth. Those people are special in this sense: of the estimated 100,000,000,000 (a hundred billion) people who ever lived (around 7.5 billion of whom are alive now), only 24 people have seen the entire earth in one glance. Just ponder that thought for a moment. Only 24 out of billions and billions.

It is strange to think that in the not too distant future, hundreds of millions of people would have seen the entire earth from space on their journeys to moon and Mars. You may think it not possible. But imagine yourself in the town of Kitty Hawk, North Carolina in December 1903. News in town is that the Wright brothers have made four powered flights — the longest of which was 260 meters, lasting 59 seconds.

So you’re at the town pub having a beer, and you tell your friends, “Imagine in a few decades, people would be walking on the moon. And what’s more, imagine that 2 billion people would fly every year at 40,000 feet, going around 500 miles an hour.” And your friends would have thought you’ve gone stark raving mad.

Two billion or so passengers take to the air every year. That number is more than the population of the earth in the year 1927. (Click on image below for more on population estimates.)

We all know that China has the largest population (1.4b), followed by India (1.3b). But which country (present day boundary) had the most people in 10,000 years ago? Guess before you look up the answer by highlighting the text between the brackets: [Mexico.]

Anyway, here’s a nice video which shows the populations of various countries over time. It’s interesting to note that China and India have been at the top spot around 6,400 years ago (4400 BCE), when India took the lead.

Fascinating to watch that video. Keep pausing the video to check out the details. For example, India’s population was 200 thousand people and China’s population was 400 thousand people around the year 8800 BCE (or 10,800 years ago), and Mexico’s population was over a million people. India caught up with Mexico about 7000 years ago, with a population of 2.4 million. Then India took the lead from China with a population of 4 million about 6400 years ago. Around 3700 years ago, India’s population was double China’s — 25 million to 12 million.

One amazing thing you notice between the 0.46 time stamp to around 1.00 minute stamp is how China’s population shrinks and grows rapidly. Wonder what that was. Anyhow, only 250 years ago, China overtook India with a population of around 190 million. China has held the lead but now India will be the most populous country in the world for the foreseeable future.

The world seems be a large place. It has to be for it to accommodate so many people. But it is really tiny compared to the size of the solar system. Nobody has seen the solar system in one glance, of course. You’d have to step far out into space to do that. But you can do a scale model of the solar system. At the scale at which the earth is a marble, the sun is the size of a balloon about 1.5 meters diameter, and the whole system is around 10 kms wide.

A bunch of guys built such a scale model of the solar system in a desert in the US. Here’s the video.

So that’s super cool. And to round this up, let’s pay attention to Carl Sagan’s little speech about the Pale Blue Dot.

Here’s the text of the video from Sagan’s book “The Pale Blue Dot: A vision of the human future in space.” It is profound and beautiful.

Look again at that dot. That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every “superstar,” every “supreme leader,” every saint and sinner in the history of our species lived there-on a mote of dust suspended in a sunbeam.

The Earth is a very small stage in a vast cosmic arena. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot.

Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.

The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand.

It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we’ve ever known.”

Oh BTW, Sagan never said “billions and billions.” And Jeffrey Epstein didn’t kill himself.

Be well, do good work and keep in touch.