Article by Dr. Sagan

The World that came to me by mail

By Carl Sagan

Dr. Carl Sagan, Director of the Laboratory for Planetary Studies at Cornell University, recipient of the United Nations Environment Program (UN) Medal in New York, as well as the Honda: "Contributions towards... a new era of human civilization."

The world came to me by mail. It came in a box labeled "fragile" and a drawing noting that it contained breakable glass. I opened it carefully, fearing to discover traces of broken glass. But it was intact. With both hands, I took it out of the box and held it up to the light. It was a transparent sphere, filled with water in a little more than half marked with the number 4210. World number 4210: there must be many similar worlds. Carefully, I placed it according to the instructions and began to contemplate it. I could see the life inside it: a set of branches, some with filamentous algae, and six or eight small animals, almost all of them pink, (at least that's what they looked like) among the branches. In addition, there were hundreds of other beings, just like fish in the waters of Earth's oceans; but they were all microbes, too small to be seen with the naked eye. Clearly the pink animals were shrimp of some kind of variety that would make them suitable for living in these conditions, which immediately caught my eye because they were so active. Some walked through the branches with ten legs, moving other appendages at the same time. Another was paying all its attention to some branches, to eat a green filament.

Between the branches, which hung with algae the way North Florida trees are covered with moss, another do as if he had other things to do somewhere else. Sometimes they changed their color depending on the environment in which they swam. Some were pale (almost transparent), while others showed a reddish-orange color.
In some ways, of course, they were different from us: they had their skeletons on the outside of their bodies, they could breathe in water, and a kind of anus was located near their mouths. They were concerned about their appearance and cleanliness, using for this a pair of tweezers that they have as a brush. From time to time one of them could be seen cleaning himself up.
But in another way they were beings similar to us, with their brains, hearts, blood and eyes. That is something that could not be overlooked. That apparently messy array of swimming appendages that they propelled through the water was in stark contrast to the precise purpose of their movements. When they arrived at their destination, they handled the filaments of the algae with the precision, delicacy and know-how of a "gourmet". Two of them, more adventurous than the rest, prowled that oceanic world, swimming above the seaweed, inspecting their domains.
After a while, individuals begin to be distinguished. A shrimp will molt, shedding its old skeleton and making room for the new one. After that, you can see something transparent, hanging rigidly from a branch, while its former occupant continues his life with his new shell. You can also see one missing a leg: has there been some angry fighting between the shrimp? Perhaps due to a sentimental fight?
From certain angles, the surface of the water is like a mirror, and a shrimp can see its own reflections. Will he be able to recognize himself?
From other angles, the curvature of the glass makes them appear larger, so I can see in detail what they really are. I notice that they have whiskers. Two of them swim to the edge of the water and turn again, inca. Then they return to the depths, casually with their arms crossed, as if to indicate that they have found nothing new with their experiment. I find them nice.
If I can see a shrimp clearly thanks to the curvature of the glass, it should also be able to see me, or at least my eye (sort of like a black disk, surrounded by a greenish-brown crown). Actually, when I sometimes start to watch someone handling the algae, it seems that they notice and look at me. We have crossed our eyes and I wonder what he thinks about what he sees.
After a day or two of worrying about work, I wake up, take a look at my glass world... and all the shrimp seem to be gone. I blame myself. I should not feed them, or give them vitamins, or change their water, or take them to the vet. All I have to do is make sure that I neither expose the system to too much light nor too much time in complete darkness and that they are always kept under temperatures of 5 to 30º C : 40-85 degrees Fahrenheit (above said limits, I imagine that a cake is being prepared and not an ecosystem). Have they died due to lack of attention? But then I see one sticking out an antennae, and I realize they're still in good health. It's just shrimp, but after a while you start to worry about them

If you're in charge of one of these worlds, and consciously care about temperature and light levels, then you eventually realize what's inside (whatever you initially thought). But if they are sick or dying, there is nothing you can do to save them. In a way, you are much more powerful than them, but they do things (like breathe in water) that you can't. You are limited, painfully limited. You wonder if it is cruel to put them in But you make sure that at least there they are safe from other dangers like whales, oil spills or cocktail sauces

The ancient skeletons that shrimp shed when molting, like the dead body of a deceased shrimp, do not remain for long. They serve as food for invisible microorganisms and other shrimp that are part of that oceanic world. That way you realize that these creatures do not work in isolation, but that some need each other. They take care of each other (in a way that I would consume oxygen from the water and produce carbon dioxide. The algae consume carbon dioxide from the water and produce oxygen. They both breathe the waste gases of the other part. Their solid waste also they complete a cycle between animals, plants and microorganisms.In this little Eden, the inhabitants are intimately related to each other.
The existence of shrimps is much more fragile and precarious than that of other beings. Algae can live without shrimp much longer than shrimp could without algae. Shrimp eat algae and microorganisms, but algae mainly consume light.
Contrary to what happens with an aquarium, this miniature world is a closed ecosystem. Light enters, but nothing else (no food, no water, no nutrients). Everything must be recycled, just like on planet Earth. In our world (much bigger) we also live off others, breathe and consume the waste of the rest. Similarly, the life of our world is sustained by light. Sunlight, passing through the air, is used by plants that combine carbon dioxide and water into carbohydrates and other nutrients, which form the food base for the animal world.
Our big world is very similar to this miniature world, and we are very similar to shrimp. But there is at least one difference: unlike shrimp, we are capable of changing our environment. We can provoke ourselves just as a careless owner of one of those crystal spheres can provoke shrimp. If we are not careful, we can overheat our planet with the greenhouse effect or cool and darken it through nuclear war. With acid rain, the hole in the ozone layer, chemical pollution, radioactivity, deforestation of tropical forests, and a dozen other assaults on the environment, we are leading our little world down paths that are difficult to understand. Our considered advanced civilization may be changing the delicate ecological balance that has been established during 4 billion years of life on Earth.
Crustaceans, such as shrimp, are much older than humans or primates or even mammals. Algae have been on Earth for about three billion years or more. They have been working together (plants, animals, microbes) for a long time. The functioning of the organisms in my sphere is ancient, much older than any culture we know of. The need to cooperate has unfortunately been lost as progress has been made in the evolutionary process. In a first phase, those organisms that did not cooperate, that did not work in common with others, disappeared. It can never occur to a shrimp, for example, to destroy a seaweed garden to build a parking lot. Cooperation is encoded in your genes. Their nature is based on cooperation.
But we humans are newcomers, emerging several million years ago. Our current technological civilization is only several hundred years old. We haven't had much experience with interspecies (or even intraspecies) cooperation. We only look at the short term and hardly think long term. There is no guarantee that we will be wise enough to understand our planetary closed ecological system, or that we will be able to modify our behavior according to that understanding. Our planet is indivisible. In North America, we breathe the oxygen generated in the Brazilian rainforest. Acid rain from polluting industries in the American Midwest destroys Canada's forests. The radioactivity of a Soviet nuclear accident compromises the economy and culture of Lapland. The combustion of coal in China heats Argentina. Diseases are spreading rapidly to far corners of the planet and require a global medical effort to eradicate. And, of course, nuclear war threatens everyone. In one way or another, we humans are united with our fellow men and with the rest of the animals or plants around the world. Our lives are interconnected.
If we are not graced with the instinctive knowledge that allows us to make our technological world a safe and balanced ecosystem, then we should try to figure out how to build it. We need more scientific research and more overly optimistic containment thinking that some "Great Owner of the Ecosphere" in heaven will take charge of correcting our environmental abuses. It's our business.
It shouldn't be so difficult as to be impossible. The birds (whose intelligence we tend to
their nest. Shrimp with brains the thickness of a thread know. The algae know it. Single-celled organisms know this. It is time for us to learn to do the same.

A Garden on Mars - By Carl Sagan

When the Apollo astronauts landed on the moon (during that brief period of exploration between 1968 and 1972) they took with them all the food they needed. It was a short trip that lasted three days. Now there is an increase in interest in the missions of men and women to the planet Mars and even an eventual exploration of other planets. But a trip to Mars can last around 9 months or more. If you take all your food, oxygen, and water with you, then you have to carry a substantial additional load, which makes the trip much more complicated and expensive, and therefore less likely.
The solution is to recycle our waste, generate our own oxygen and produce our interplanetary carrying a human crew should become something like a closed ecosystem. It must contain non-human life, especially plants.
If we humans venture far from Earth, we must make or convert our spaceships into gardens.
Serious studies on similar systems are underway. For example, the commercially available EcosphereÒ) described in this article was developed by Joe Hanson at NASA's Aerospace Propulsion Laboratory.
However, until now it is the Soviets who have carried out the most elaborate attempts to assemble ecologically closed systems in which human beings are a part. At the Siberian Research Institute in Krasnoyarsk there is a facility called BIOS. In it, some individuals live their daily lives for periods of time sufficient to reach Mars. The longest stay has been five months, but one researcher has stayed inside for more than 13 months in multiple experiments. Coupers are reportedly given only one-fifth of the food they will need, and neither air nor waste product removal. Nothing really goes in or out except electricity and radio waves. Everywhere you can find hydroponic tanks. Likewise, BIOS is full of plants (dill, wheat, peas and many other vegetables) that grow in nutrient media without soil. The “travellers” prepare their own bread. Vegetation generates oxygen. The waste is recycled. It is still in the learning phase. They have an oven in which everything that is not edible (such as roots and stems) is incinerated. Initially, the catalysts did not work well, and slowly the cabin began to fill with poisonous nitrogen oxides from the furnace. Wheat growth slowed considerably, and potato leaves began to wrinkle. Plants detected a problem before humans did. When the catalysts responsible for removing harmful gases were replaced, the air became purer again and the plants revived.
These systems are being refined and will play an important role in future human exploration of the solar system. There is nothing forcing such ecologically closed systems to be attached to spacecraft. After astronauts and cosmonauts land on Mars, their food, air, and water can continue to be provided by the same plants that accompanied them on their long journey. Sunlight and other sources of energy will be available, and Mars itself could be made to contain oxygen and water.
Perhaps, in the future, self-sustaining ecosystems will be located on Mars, oases that will be stations of stay and travel for the explorers of the 21st century.

Parade Magazine by Carl Sagan 1986.
Authorized translation of the article “The World that Came in the Mail / A Garden for Mars”