O'Neill's cylinder

Artistic recreation of an O'Neill cylinder.

Much more accessible than the sphere of Dyson , of which we spoke a few weeks ago as a possible megastructure of a hypothetical Type II civilization on the Kardashev scale, O'Neill's cylinder could be a goal attainable in the near future, and according to some experts would make more sense than the attempt to colonize Mars or other planets.

In the 1970s, particle physicist Gerard K. O'Neill raised the possibility of building orbiting colonies around Earth as an alternative to the colonization of other planets. According to O'Neill, the fact of having always lived on the surface of a planet has induced us a kind of "planetary chauvinism" that makes it difficult to conceive of other possibilities; but colonies in orbit would be much more comfortable, safe and accessible habitats than other Earth-like or terraformed planets.

O'Neill raised the possibility of building colonies in orbit around the Earth as an alternative to the colonization of other planets

The simplest orbital space colony design, which O'Neill called Isla Uno, is a Bernal sphere (the idea was first proposed in 1929 by physicist John D. Bernal): a hollow sphere of 1.6 km of diameter that would rotate about an axis so that in its inner face and in the equatorial zone would have, by effect of the centrifugal force, an artificial gravity equal to the terrestrial one. O'Neill's version is smaller (about 500 m in diameter), and would be surrounded by adjustable mirrors that would reflect the light of the Sun to illuminate the interior of the sphere by large windows located at the poles. As we moved away from the equator, the artificial gravity would diminish until it was annulled at the poles, which would allow us to carry out all kinds of activities and experiments in low gravity.

Island Two or Toro de Stanford is a toroid of 1.8 km in diameter capable of harboring a population of about 10,000 people, that would revolve around its geometric center to supply in the inner face of the part of the ring farthest from the center a gravity of about 1 g.

O'Neill's Three Island or Cylinder is a set of two huge cylinders connected and of opposite rotation (to neutralize the gyroscopic effect). The cylinders would have, in their most ambitious version, 32 km long by 6.4 km in diameter, and could house several million people. One of the major advantages of the cylinder over other geometric forms is that on the entire interior surface there would be the same artificial gravity, whereas in the sphere or toroid only a strip would enjoy this requirement, essential for a sustained habitability.

Rotation speed

I have not planned my wise readers for a long time. It's a problem for those who need to make numbers, so I'm going to ask them to unpack their school physics books and calculate the speed at which the different "islands" of O 'Neill to supply the settlers with an artificial gravity similar to that of the earth. And if they do not want to resort to the old school formulas, they can also approach it as a " Fermi problem " and find approximate values ​​through an ingenious approach.

And it goes without saying that if someone comes up with other concepts or designs of space colonies, do not stop to raise them in our section of comments.

by: el pais