But then the lecture picks up speed and I begin to listen. Ulrich Walter speaks of "technology known today", ... "but not of costs". The O'Neill cylinder is not a kitchen appliance, but a spaceship with two cylinders of 6.4 km in diameter and 32 km in length each. With gravitation generated by centrifugal force and a settlement area of 1,300 km2. With forests, rivers, fields, clouds and birds, it offers space for millions of people (I missed how they were all to fit in). Such a rotating, green island in icy cold. Why should people not want to live in space under such conditions, he asks.
Elon Musk will soon be launching missiles for the first Mars inhabitants. 200 days there, 200 days back. Mars does not have a sufficient atmosphere, but one could create it. Terraforming Mars is what they call it. We already have a lot of experience with the deformation of the earth's atmosphere. Unlike the moon, Mars has frozen polar caps. From CO2. That's it. That's the greenhouse gas of which we're blowing too much into the air here on earth. Mars has water under its surface for this purpose. So, if the Earth's citizens do not want to travel in space suits and oxygen devices in the icy Mars desert, they need an earth-like atmosphere there. And this is how it works: with a little greenhouse gas PFC, the Mars atmosphere can be raised to -20 degrees Centigrade within the next 500 years. Then the poles will melt and the CO2 will be released. This further condenses the atmosphere and increases the greenhouse effect. At zero degrees Centigrade the ice melts and plants can be sown. In another 500 years, they have produced so much oxygen through photosynthesis that the inhabitants of Mars can take off their suits and live in similar conditions to the earth. And that is when the fun only begins. From there again, 10 million humans in hydrogen driven space arks with ten percent speed of light can reach the next earth-like planet in about 300 years, regenerate and multiply there in about 10,000 years and reach the next and yet again the next planet. Until our Milky Way, our galaxy, (100,000 light years in diameter, 100 thousand million stars) is completely inhabited by humans in just 3.9 million years (Monte-Carlo calculation). This is a short part of the 20,000 million years that our Milky Way still exists. Too far away? And takes too long to think about? Our sun was formed 5 thousand million years ago. 65 million years ago, a comet's impact ended the life of dinosaurs on earth. So, 3.9 million years is a short period in this context. And in 80,000 years, researchers expect a massive ice age. At the latest then it will become uncomfortable on earth and an emigration to Mars, which has been planted with vegetation in the meantime, will no longer be quite so absurd. But the whole thing has then also reached its natural limit. While a flight to the next stellar system still seems possible, albeit as a pure vision, journeys to the next galaxy are no longer imaginable, since even light needs 2.5 million years to get there. Why has this vision of the incomprehensible and infinite moved me so much? After all, real estate is no rocket science. Why think about such periods? Hardly anyone who reads these lines will live longer than half a century more. Doesn't this scientific-technical utopia from the 70s distract from our real problems?
The politicians act in strictly limited periods of time, usually in legislative periods of four years. Stock corporations can be measured in quarters. The real estate industry thinks from deal to deal, project to project. Fast, faster and faster yet planning and building, submitting the building application even earlier and then quickly reselling. This results in some kind of manic frenzy. But in dynamic times, with their unpredictable changes and disruptions, overly ambitious goals and visions are doomed to failure at an early stage. Within just a few years, the international space stations have become so contaminated bacterially that they will have to be dropped and sunk into the sea sooner or later. And the astronauts on their way to Mars are exposed to such strong radiation that they will develop cancer. The pyramids, Greek temples, Gothic cathedrals, English landscape gardens, Brasilia or the workers' settlements in Berlin are built utopias. They each embody a social ideal and are far ahead of their time. With this idea on board, it makes sense to see the earth and the world population as a whole and in its diversity. And to develop our societies and cities from a target perspective. Driving without sight must lead to despair. Those who see themselves as victims of digitisation, globalisation, terrorism, housing shortages or gentrification have their sights set on descent and cannot be confident. Those who drive with sight need headlights at night and destinations.
So, what are the visions and great beliefs that can unfold a unifying effect? It's about turning profit into meaning. For me it is about the democratic, diverse, creative urban society with its inclusive institutions. It must be strengthened and developed. Their home is our mission. It is the cities of the earth in which the future of mankind is decided. They are the most complex and challenging thing humans have ever produced. It is our task to shape them in such a way that pluralistic societies will thrive today and tomorrow and, as a whole and individually, turn for the good and better. The flight to Mars, on the other hand, is child's play.