Squooshing people together and making a long line

We've been living on Earth and growing our population since, well, when there was a population. But the Earth's surface area stays the same. This thought makes me uncomfortable, I see an issue here, in this statement - people live on a planet that doesn't get any bigger, and the number of people does get larger. Inevitably, time will come when there will be no more space left on Earth for more humans, if everything else remains the same.

I've been thinking of a scenario where our existence didn't require too much space individually, just us standing there, next to each other, and everything was happening virtually. We might have some sort of charging equipment to replace food intake to somehow continue living but that's all we need. Everyone could occupy just a small square and live happily, though that's not relevant. It doesn't sound very thrilling, but still, I wanted to find out how mach space we would need in that case, how many people could be living on our planet at any given time.

How much territory would it require if all the people in the world were to stand next to each other?

We have our planet and we have people living on it. Let's squash them together and see how much space is needed. Let's assume each person needs just 0.5 square meters (about 5.4 square feet) space, and we know that the world's population is 8 billion. If 1 person needs a 0.5 sq meters space, 8 billion people would need 8 billion times more than that.

8x10^9 * 0.5 m^2 = 4x10^9 m^2 = 4x10^3 km^2

Huh, all we need is a 4,000 square kilometers, or about 1,550 square miles. That's about the size of the Metropolitan area of Marseille, a lovely city in France. If we, and I mean all of us, were to have a meeting with Batman (yup, he moved to France, and started organizing global events), we'd just need to get to Marseille and we would all fit.

Obviously, we would need to get rid of all the buildings and other stuff that's not just the ground, but the idea is that we'd fit there.

So we got that, if we all gathered side by side we'd need just 4,000 square kilometers, if we wanted to give each person 1 square meter, that would require just twice as much space, 8,000 square kilometers or about 3,100 square miles. This time we'd be destroying the London Metropolitan area which is 8,382 square kilometers, fortunately for London some 300 square kilometers area can be left untouched, what should be keep?

To be honest, I was expecting more, just the number 8 billion sounds a lot. And it is a lot, it's that humans are tiny (or the space we allocate for each one of them is), also the Earth is quite a large place.

What if instead of the current population, we took the number of people who have ever lived on Earth? That is 117 billion, only 117 billion people have ever lived on Earth. That doesn't seem a very big number for all the people ever lived, does it? In any case, let's see where this many people would fit on Earth if they were standing next to each other:

117x10^9 * 0.5 m^2 = 58.5x10^9 m^2 = 58.5x10^3 km^2

That's just 58,500 square kilometers or about 22,600 square miles, it would cover the entire territories of Croatia (56,000 sq km) and Luxembourg (2,500 sq km). Now Croatia and Luxembourg are lovely countries, but they are just 2 quite small countries, one way smaller than another, but still small compared to the Earth.

The Earth indeed is a large place, but how large is it? How many humans it would take to fill the whole planet.

How many people standing next to each other would it require to fill all of the Earth's surface?

Earth's surface area: 510.07 million square kilometers (196,940,000 square miles)
Water: 361.13 million square kilometers (139.43 million square miles)
Land: 148.94 million square kilometers (57.51 million square miles)

We don't want to stand on water, because some of us actually can't, so we'll gather only on land.

We want to figure out how many humans can fit on the planet standing next to each other each one of them occupying 0.5 square meters. We're going to destroy everything the human kind has ever built so far so that people could stand there for some global stand-up consensus. Sounds like a reasonable idea. And all we need is to divide the Earth's land area into a lot of 0.5 square meter areas.

If we were to do that, get rid of everything so that all we have is just ground, my initial idea was to throw everything else into the oceans. But that would cause water levels to increase among other bad events, and even in the "best" scenario where nothing else happens, the land area would decrease. I don't really know how much stuff there is to throw into waters, how that would affect us, so let's instead send everything to space, keep them somewhere safe and we can bring them back after the consensus is over. It shouldn't take that long anyway.

Also on this imaginary Earth there are no animals, they figured out how to travel to other galaxies and left the Earth, they're all safe in their new home planet.

To figure out how many humans can stand next to each other all over the planet, we just need to divide the planet's land area by 0.5 square meters, because that's how much every human gets.

148.94 * 10^6 km^2 148.94 * 10^6 km^2
------------------ = ------------------ = 297.88 * 10^12
0.5 m^2 0.5 * 10^-6 km^2

There are 298 trillion small squares, we need 298 trillion people. That's a lot of people. That's actually a lot of people.

About 300 trillion, 3 with 14 zeros, that's a big number, let's see how big it is.

During a year the Earth travels about 940 million kilometers, that's the length of its orbit around the Sun. Imagine a scenario when after traveling every 1 meter, our lovely Earth asks one of the 297.88 trillion people to "step out" and "stand there", for no particular reason, and I leave the "stepping out" and "standing there" parts to your imagination.

Given that people would need to be living quite long lives and eager to do as told by the mother earth, it would take the Earth about 317 thousand years to get rid of us. That seems like a very long time compared to human life and that's about the same amount of time since the early (anatomically) modern humans emerged. By the way, in this scenario nobody dies and nobody else is born.

If there were this many people and they all were to stand in a long line 0.5 meters apart, very politely and not making complains, it would make a line 149 billion kilometers or 92.6 billion miles long.

It took me a while to appreciate how long this line would be. Too long. To make sense of this, let's compare the length of this line to other large distances we know. Here are some ideas:

The average distance between the Earth and the Moon is about 384,399 km. 149 billion kilometers long line would cover the Earth-Moon distance about 390 thousand times.
Our line would cover the space between the Earth and the Sun about 1000 times. By the way, scientists use this distance between the Earth and the Sun as a unit of measuring other longer distances. It is called an astronomical unit (AU) and it's 149,600,000 kilometers. Our line is almost a thousand AU.
It would take 5 days and 18 hours for the light to travel from the first person to the last person of this line. Light travels ~ 300,000 kilometers per second.

So, what did we learn? Nothing really, it's just fun to think about people and the universe, our place in this world, and if there are numbers that's just a big bonus.

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