The following text is excerpted from the booK:
Seeding the Universe with Life:
Securing Our cosmological Future

1. Basic Concepts of Astroecology

In this relation, two strategies to expand life in space may be considered, using natural or modified biology and environments. The natural approach would colonize planets, asteroids and comets in their natural form and under their natural environments. This colonization may progress unaided by such means as panspermia that is mediated naturally by meteorites and comets, or through directed panspermia. The colonizing organisms may be natural or optimized for the new environments, but in either case biological gene/protein life forms that spread, reproduce and evolve by natural means. This may be called natural colonization.

The second type of colonization can alter planetary materials deliberately and construct habitats with environments optimized for life. This type of colonization may be termed "terraforming" or, more generally, "ecoforming". Initially, the designed environments may be Earth-like to accommodate present organisms. Later, "ecoforming" may create different environments suited for altered biologies. Technological colonization may also direct biological evolution in the new habitats by genetic engineering, and may use robots or man-machine composites.

Whether genetic engineering or natural mutation will direct evolution, its development will be dictated by the need to survive in the new environments. The Logic of Life, test by survival, will continue to select the successful species. The mechanisms of evolution may change, but the Logic of Life, selection by survival, is immutable and permanent.

Applied astroecology on the other hand depends on ethical motivation. Given the principles of panbiotic ethics, the objective is to maximize the amount of life in a given biosphere, from the local to the cosmic level. In mathematical terms, the objective is to maximize the term BIOTA =  (Integral of) B(t)dt, where B(t) is total biomass as a function of time (BIOTA = "Biomass Integrated Over Times Available"). The integrated amount of life can be maximized by using as much of the available resources in the universe as possible, converting them to biomass, and ensuring that the resulting biota will survive as long as possible. Ultimately, we want include all the useable material in the universe in the biomass, and allow life to inhabit all the accessible space and time. In addition, as humans, we may also want to maximize the amount of sentient life, that is, to make as much of the biomass as possible part of sentient life. In the long run, all the biota may constitute sentient beings. Incorporating all the biologically useable material in the community of life (biota), and making all life sentient, will maximize cognitive life (their total interactive community may be called "cognota") or post-human life in habitable space and time in the universe.

Isolated conditions on island habitats on Earth lead to the divergence of colonizing organisms into different species. Similarly, Life through space will be able to explore the variety of life forms that biology allows, with each new branch of evolution suited to a different environment. In many cases designed evolution will be needed, as adaptation will necessitate major and abrupt changes. Gradual natural evolution cannot accomplish this, but once major design changes have been implemented, natural evolution can fine-tune the new species to their local environments. It is remarkable that genetic engineering and space technology, which require each other, are arising simultaneously.

Life, including humans, will in turn transform new habitats. For example, terraforming will introduce habitable temperatures, liquid water and oxygen atmospheres to the colonized bodies. The organics in these objects will be incorporated into biomass. Non-biological organics will be transformed into living matter and the inorganic matter in these objects will be transformed to serve this new biota. In this process, asteroids and comets may be turned into glass, metal, soils and polymers.

Silicates, metals, organics and ices similar to those on Earth are common in planets, meteorites and comets in our Solar System and even in interstellar clouds. Since the basic laws of chemistry are universal, other solar systems must also be made of similar materials. As on Earth, biology will transform these materials into living matter and its supporting matrix, in this galaxy and in others.

In fact, the studies discussed in the next sections show that the biological fertilities of materials in these space objects are similar to terrestrial analogues. We can therefore extrapolate from ecology on Earth and from meteorite microcosms to assess the potential ecology of the Solar System. Further, estimating the prevalence of solar systems allows extrapolating to galactic and cosmic ecology. These studies allow estimating the potential population of the galaxy and of the universe.

In the long term, humans will colonize the neighborhoods of brown dwarfs that may be habitable for trillions of years; shape interstellar clouds to form desirable seized stars; mine and merge stars, and harvest black holes. All of the galaxy may be converted into living matter and its supporting matrix. This new animated galactic matter will continue to shape its own future to best accommodate life. At this stage the galaxy will constitute an interconnected living being. In this sense, when Life comes to the universe then the universe itself will come to life.

In the distant future, our successors may try to induce new Big Bangs and may even transform the laws of physics to extend molecular Life indefinitely. If this is not possible, life will have to transform itself into sentient beings constituted, possibly, of elementary particles and electromagnetic fields. At that distant time, conscious organized matter of any kind may qualify as living beings.

However, these developments are remote and uncertain. The universe seems able to stay habitable for biological life for trillions of years. The past 14 billion years from the moment of Creation may only be a fleeting moment in the total span of Life. It is impossible to predict with any certainty this long future of the universe and of the Life that it harbors, from the few fleeting eons of the past.

The objective of panbiotic ethics is to expand Life to its maximum throughout this vast future. While contemplating the distant future is uplifting, it is also uncertain. We cannot foresee how our distant descendants will promote Life in the universe. As for us, we can take the first steps to assure that our descendants will exist to do so.

Terrestrial life, including humans and their supporting biota will first expand in our Solar System (Solys) before colonizing other star systems. In order to understand this expansion we need to investigate the ecology of the Solar System starting with its biological resources.

Space colonists and their environments may be very different from their current forms. In fact, genetic engineering will be critical in adapting terrestrial life to space. We shall report below the first encounter of a genetically engineered microorganism with space materials. The first space colonists and their biological infrastructure will likely to consist of contemporary species. Correspondingly, our experimental studies concern the interactions of contemporary organisms with meteorite/asteroid materials.

The first space habitats are likely to be established in large colonies in space, on asteroids or Mars. The most accessible sources of water and organics for the space colonies are the carbonaceous chondrite C-type asteroids, found mostly between Mars and Jupiter.

The hydrous silicate rocks contain about 2% water in the CV3 meteorites, 3 - 11% water in the CM2 meteorites and 17 - 22% water in the CI meteorites. The rocks in carbonaceous C-type asteroids should have similar water content. The settlers may extract the water simply by heating it in solar furnaces. Later, larger quantities of organics and water can be obtained from icy comets.

The asteroids are also sources of carbon-based organic molecules. The CI type carbonaceous chondrite meteorites contain the largest amounts of organics, about 10-15% by weight. The second and most abundant class of carbonaceous chondrites is the CM2 meteorites. The much-studied Murchison meteorite that fell in Australia in 1969 is in this class. It contains about 2% organics, of which about 70% are a solid polymer similar to coal. The rest of the organics in CI and CM2 meteorites include hundreds of various compounds, especially organic acids like acetic acid that is found in vinegar, as well as alcohols, nitriles, and hydrocarbons similar to petroleum and soot. They even contain amino acids, some of which are the same as the constituents of proteins. Even adenine, a component of DNA, is found in the meteorite. However, the presence of many non-biological organics suggests that the organics are not of biological origin but the result of other chemical processes. A third type of carbonaceous chondrites, the CV3 meteorites such as Allende contain less than 1% organics, mostly hydrocarbons.

On Mars, organic compounds may be produced from atmospheric carbon dioxide and also from imported organics from the Martian moons Phobos and Deimos. Organics from carbonaceous chondrite asteroids can be also imported.

Can life survive on these asteroid materials? If so, how much life can these resources support? We addressed these questions by measuring the nutrient contents of these materials and by growing living organisms on them. From these studies we can find out how much biomass each kilogram of the asteroid materials can support, and multiplying this by the total mass of asteroid materials yields the total sustainable biomass.

For the nutrient and biological studies we constructed small planetary microcosms using typically about one tenths of a gram to one gram of meteorite materials. We inoculated these microcosms with various microorganisms, algae and plant tissue cultures. The material requirements for these microcosms are described in the box below and in the Appendix.

Similar materials in other solar systems may also support microorganisms planted there through directed panspermia by space-borne generations.

All life in the Solar System can rely on solar radiation energy. The span of the present phase of the Sun is about five billion years. We shall estimate later the amount of life that can exist in this Solys during this period.

 Our further steps in space may reach the comets that contain minerals similar to the carbonaceous asteroids, but in quantities at least a hundred times larger. The space-borne populations that reach the comets will be able to convert all of their elemental contents for biological use. This may be accomplished with simple technology such as solar ovens. Recent research confirms that material in carbonaceous asteroids and comets can support life. These objects can be accessed easily and their materials can be transported readily because of their low gravity. They can be used as soils or in hydroponics when processed only by heating and extraction.

The populations in space can spread Life by directed panspermia, and possibly by interstellar colonization. This may start as soon as the technology is ready in some thousands of years. At the latest, interstellar colonization may become necessary when the sun becomes a red giant, which will make the inner planets unlivable. Life can then move further out to the Kuiper Belt of comets, and will also have more incentive to colonize other solar systems. Likely habitats will then be the red dwarf stars with lifetimes of trillions of years and brown and white dwarfs that can last even longer. One of these white dwarfs will be our Sun, which may then be habitable for an unimaginably long 10²⁰ years, that is, a hundred million trillion years. In these stages, the amount of life will depend on energy rather materials. Added up over the vast scale of time the total amount of life about the white dwarfs will amount to numbers on a cosmic scale.

Finally, we can imagine that Life becomes powerful enough to use all of the ordinary baryonic matter in the galaxy, maybe through the universe, for materials and energy. Knowing the amount of available matter, we can estimate the ultimate amount of life that appears possible according to the current projections of cosmology.

The scope of future life surpasses the capacity of our real comprehension. Nevertheless, all of the above steps are within the bounds of physics.

In the following estimates, we consider the prospects for our family of organic, cellular, gene/protein life. Maybe the laws of nature can be transformed to extend this life even further, even to infinity. Maybe there is life in other universes or maybe new universes can be created. More abstract definitions may be needed if we wish to extend "life" even further. Maybe we can create patterned oscillation of cognitive electromagnetic fields that will last forever. Maybe there is some kind of self-reproducing order at other levels of magnitude in infinitely embedded universes. Does it matter if this abstract life will exist? We must leave these decisions to our remote descendants. As for us, we will fulfil our purpose if we assure that our descendants can enjoy the expanses of the future and reach for the ultimate.

Can life survive on materials that compose carbonaceous asteroids and comets? If so, how much life can these resources support? We can answer these questions by measuring the nutrient contents of these materials and by growing living organisms on them. From these studies we can find out how much biomass each kilogram of the asteroid materials can support. If we also know how much material the asteroids and comets contain, we can calculate the total amount of living matter that these resources can sustain. The method to calculate these amounts is described in the Appendix.

For the nutrient and biological studies we constructed small planetary microcosms, typically about one tenth of a gram to one gram in size. We inoculated these microcosms with various microorganisms, algae and plant tissue cultures. The material requirements for these microcosms are described in the box below, and the results are described in the following sections.

The most direct way to expose life forms to extraterrestrial materials to is to inoculate meteorite samples with microorganisms. Nature has been performing these experiments for eons as microorganisms colonized some interplanetary dust particles, comets and meteorites that fell on Earth. Similar materials could have supported microorganisms in space in the past when the carbonaceous asteroids contained liquid water. The water contained nutrient salt solutions for autotrophic microorganisms that manufacture their own organics such as algae, and organic compounds for heterotrophic bacteria and fungi that require organic nutrients.

These first observations were followed by controlled experiemnts with Murchison extracts. The extracts were prepared by heating 0.05 - 0.2 grams of powdered Murchison with 1 milliliter of water under sterlizing autoclave (pressure-cooker) conditions, at 120 C for 15 minutes.

The extracts were then inoculated with a relatively small amount, usually 100 to 1,000 microorganisms. We followed the growth of the microorganisms with time by plating a small sample of the solutions on agar plates and counting the number of microbial colonies. We compared the growth of the microorganisms in the meteorite extracts with the growth in extracts of various minerals and soils and in optimized growth culture media. The populations in the Murchison extracts reached over 10⁶ viable colony-forming units (CFUs) per milliliter, similar to those in solutions of agricultural soils, and only ten times less than in the optimized growth medium. In more diluted extracts of the Murchison meteorite the bacterial populations were somewhat smaller.

To test if meteorites can sustain complex ecosystems, the meteorite extracts and wetted meteorite solids were inoculated with a mixture of microbes and algae from a wetland. The results showed that the microorganisms and algae grow on these materials, even in the concentrated solutions that are formed on meteorites wetted by a small amount of water. Table 3.1 lists the microorganisms and their populations in these cultures.

TABLE 3.1 Microbial and algal population (in units of thousands) found per milliliter of solution on wetted meteorites that were inoculated by microorganisms from a peat bog:

After the microorganisms establish fertile soils, the colonized biospheres will need to accommodate higher life forms, including plants. We therefore tested if the asteroid and planetary materials can support plant growth.

Biological tests tend to yield a range of results and a fair number of replicate copies of each sample were needed for reliable statistics. In our experiments we measured plant yields in terms of the weights of the product plants. Meaningful statistics required 6 – 10 replicates. However, the amount of meteorite materials available for these tests was limited. Often only one hundredth of a gram (10 milligrams) of material was available to make extracts for each cultured plant. This amount can yield only very small plants.

A way around this problem was to use tissue cultures in which the growth of very small, millimeter-sized plants can be observed. The tissue cultures were grown by taking a small section from the growing tip of a plant such as asparagus or potato, and placing it in a large drop, about 0.1 milliliters, of the meteorite extracts. The extracts also contained a few milligrams of ground meteorite powder. Sucrose and nitrate were also added to most cultures as a source of carbon and nitrogen because meteorites are poor in these nutrients. Media made this way constitutes small hydroponic solutions. Hydroponic cultures are in fact likely to be used in space missions and habitats. Some of the cultures also contained small amounts of the ground-up meteorite "soils". The cultures were grown in small vials, placed in growth chambers under controlled conditions.

0.05 milliliters of the meteorite extracts, plus about 5 milligrams of meteorite dust in some experiments. After about six weeks, the cultures grew into small plants a few millimeters in size, weighing from a few tenths of a milligram to a few milligrams. Once they reached their final size the plants were photographed under a microscope and weighed. A few plants were also analyzed for their elemental content, to find out how much of each nutrient was absorbed from the meteorite medium.

One of the requirements of a good test organism is that it should discriminate amongst the various media. In this respect the asparagus tissue cultures performed best. The average weights obtained in the various extracts were: Murchison, a carbonaceous chondrite meteorite, 0.32 mg; DaG 476 Martian meteorite, 0.44 mg; EETA 79002 Martian meteorite, 0.58 mg; all greater than the yield of reference samples in water, 0.23 mg. The plants grown in all of the meteorite and rock extracts were also larger and greener than those grown in plain water. This shows that they used nutrients from the meteorites. The elemental analysis of the product plants also showed that they incorporated these meteorite nutrients.

Biological yields depend on available nutrients. Scientists measure nutrients by extracting them from soils, simulating natural processes. Our experiments simulated the extraction of nutrients by pure water that would have happen in early asteroids that contained water, and in meteorites that fall on planets. The carbonaceous chondrites will be also extracted by water in space colonies where they will be used as soils or as hydroponic media. To reproduce these various conditions in our experiments, we used pure water for the extractions, moderate temperatures of 20^o C, and extraction times of 1 – 4 days.

In some cases, the extractions were performed under conditions that sterilized the materials at temperatures of 120^o C for 15 minutes, which resembles the conditions in early asteroids. In addition, we also extracted some nutrients under carbon dioxide atmospheres that simulated early Earth and Mars. The amounts of the extracted nutrients varied little, mostly by less than a factor of two, under these various conditions.

Plant nutrients extracted from soils were divided into macronutrients, which are required in substantial amounts in the biomass, and micronutrients that are required in trace amounts. Tables in the Appendix list the required macronutrients by bacteria, mammals including humans, in human brains and in average biomass.