Freeman Dyson Freeman John Dyson (15 December 1923 – 28 February 2020) was an English-American theoretical physicist and mathematician known for his works in quantum field theory, astrophysics, random matrices, mathematical formulation of quantum m ...

proposed that

trans-Neptunian object A trans-Neptunian object (TNO), also written transneptunian object, is any minor planet in the Solar System that orbits the Sun at a greater average distance than Neptune, which has a semi-major axis of 30.1 astronomical units (au). Typicall ...

s, rather than

planet A planet is a large, rounded astronomical body that is neither a star nor its remnant. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a ...

s, are the major potential habitat of life in space. Several hundred billion to trillion

comet A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or Coma (cometary), coma, and sometimes also a Comet ta ...

-like ice-rich bodies exist outside the orbit of

Neptune Neptune is the eighth planet from the Sun and the farthest known planet in the Solar System. It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 time ...

, in the

Kuiper belt The Kuiper belt () is a circumstellar disc in the outer Solar System, extending from the orbit of Neptune at 30 astronomical units (AU) to approximately 50 AU from the Sun. It is similar to the asteroid belt, but is far larger—20 t ...

and Inner and Outer

Oort cloud The Oort cloud (), sometimes called the Öpik–Oort cloud, first described in 1950 by the Dutch astronomer Jan Oort, is a theoretical concept of a cloud of predominantly icy planetesimals proposed to surround the Sun at distances ranging f ...

. These may contain all the ingredients for life (water ice, ammonia, and carbon-rich compounds), including significant amounts of

deuterium Deuterium (or hydrogen-2, symbol or deuterium, also known as heavy hydrogen) is one of two Stable isotope ratio, stable isotopes of hydrogen (the other being Hydrogen atom, protium, or hydrogen-1). The atomic nucleus, nucleus of a deuterium ato ...

and

helium-3 Helium-3 (3He see also helion) is a light, stable isotope of helium with two protons and one neutron (the most common isotope, helium-4, having two protons and two neutrons in contrast). Other than protium (ordinary hydrogen), helium-3 is th ...

. Since Dyson's proposal, the number of trans-Neptunian objects known has increased greatly. Colonists could live in the

dwarf planet A dwarf planet is a small planetary-mass object that is in direct orbit of the Sun, smaller than any of the eight classical planets but still a world in its own right. The prototypical dwarf planet is Pluto. The interest of dwarf planets to ...

's icy crust or

mantle A mantle is a piece of clothing, a type of cloak. Several other meanings are derived from that. Mantle may refer to: *Mantle (clothing), a cloak-like garment worn mainly by women as fashionable outerwear **Mantle (vesture), an Eastern Orthodox ve ...

, using

fusion Fusion, or synthesis, is the process of combining two or more distinct entities into a new whole. Fusion may also refer to: Science and technology Physics *Nuclear fusion, multiple atomic nuclei combining to form one or more different atomic nucl ...

or geothermal heat and mining the soft-ice or liquid inner

ocean The ocean (also the sea or the world ocean) is the body of salt water that covers approximately 70.8% of the surface of Earth and contains 97% of Earth's water. An ocean can also refer to any of the large bodies of water into which the wo ...

for

volatiles Volatiles are the group of chemical elements and chemical compounds that can be readily vaporized. In contrast with volatiles, elements and compounds that are not readily vaporized are known as refractory substances. On planet Earth, the term ...

and

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. ...

s. Given the light gravity and resulting lower pressure in the ice

or inner ocean, colonizing the rocky

core Core or cores may refer to: Science and technology * Core (anatomy), everything except the appendages * Core (manufacturing), used in casting and molding * Core (optical fiber), the signal-carrying portion of an optical fiber * Core, the centra ...

's outer surface might give

colonists A settler is a person who has migrated to an area and established a permanent residence there, often to colonize the area. A settler who migrates to an area previously uninhabited or sparsely inhabited may be described as a pioneer. Settl ...

the largest number of

and

volatile Volatility or volatile may refer to: Chemistry * Volatility (chemistry), a measuring tendency of a substance or liquid to vaporize easily * Relative volatility, a measure of vapor pressures of the components in a liquid mixture * Volatiles, a gr ...

resources as well as insulating them from cold. Surface habitats or

domes A dome () is an architectural element similar to the hollow upper half of a sphere. There is significant overlap with the term cupola, which may also refer to a dome or a structure on top of a dome. The precise definition of a dome has been a m ...

are another possibility, as

background radiation Background radiation is a measure of the level of ionizing radiation present in the environment at a particular location which is not due to deliberate introduction of radiation sources. Background radiation originates from a variety of source ...

levels are likely to be low. Colonists of such bodies could also build rotating habitats or live in dug-out spaces and light them with

fusion reactor Fusion power is a proposed form of power generation that would generate electricity by using heat from nuclear fusion reactions. In a fusion process, two lighter atomic nuclei combine to form a heavier nucleus, while releasing energy. Devices de ...

s for thousands to millions of years before moving on. Dyson and

Carl Sagan Carl Edward Sagan (; ; November 9, 1934December 20, 1996) was an American astronomer, planetary scientist, cosmologist, astrophysicist, astrobiologist, author, and science communicator. His best known scientific contribution is research on ...

envisioned that humanity could migrate to neighbouring star systems, which have similar clouds, by using natural objects as slow interstellar vessels with substantial natural resources; and that such interstellar colonies could also serve as way-stations for faster, smaller interstellar ships. Alternatively Richard Terra has proposed using the materials from the Oort-cloud objects to build vast starlight collecting arrays to power habitats, thus making an Oort-cloud community essentially independent of its central star and fusion fuel supplies.Richard P. Terra, "Islands in the Sky: Human Exploration and Settlement of the Oort Cloud", in ''Islands in the Sky: Bold New Ideas for Colonizing Space'', Stanley Schmidt and Robert Zubrin, eds. Wiley, 1996,

References

Bibliography

*Freeman Dyson, "The World, the Flesh, and the Devil", Third J.D. Bernal Lecture, May 1972, reprinted in Communication with Extraterrestrial Intelligence, Carl Sagan, ed., MIT Press, 1973, *Richard P. Terra, "Islands in the Sky: Human Exploration and Settlement of the Oort Cloud", in Islands in the Sky: Bold New Ideas for Colonizing Space, Stanley Schmidt and Robert Zubrin, eds. Wiley, 1996, *Ben R. Finney and Eric M. Jones, eds., Interstellar Migration and the Human Experience, University of California Press, 1986, *David G. Stephenson, "Comets and Interstellar Travel", in Journal of the British Interplanetary Society, 36, 1983, pp. 210–214. {{DEFAULTSORT:Colonization Of Trans-Neptunian Objects +Trans-Neptunian objects Freeman Dyson Trans-Neptunian objects