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A Hitchhiker's Guide to Astrobiology
By Aaron Gronstal

Looking for Microbial Martians
By David Tenenbaum

Space on Earth

STONEs in Space
By Leslie Mullen

Building a Habitable Earth
By Simon Mitton

The Origin of Life:
First Steps

By Toby Murcott

The Violent Origin of the Solar System
By Simon Mitton

Summary: In his book, “Space on Earth,” microbiologist Charles Cockell urges space scientists and environmentalists to work together for the future for humanity.


Space on Earth

Must we choose between Heaven and Earth? Space enthusiasts often deride environmentalists as being too inward-looking and focused on the past, with their fight to preserve Earth’s ecosystems and natural resources in the face of humanity’s push for development. Likewise, those concerned about Earth’s problems often look askance at space enthusiasts as being too outward-looking and future-focused, with their search for what lies beyond our home planet, their dreams of human colonies in alien star systems, and their certainty that emerging technologies will cure whatever ails us.

Yet in his book, “Space on Earth,” microbiologist Charles Cockell says the seemingly disparate disciplines of space and environmental science share common goals, and both would be better served by joining forces.

“Space on Earth: Saving Our World By Seeking Others,” by Charles S. Cockell. Published by Macmillan, November 2006.
‘It is not uncommon to find environmentalists who regard space exploration as a waste of money, an activity that draws off resources when we should be solving problems at home,” Cockell writes. “On the other hand, I have met space settlers who regard environmentalists as Luddites, peering inwards to the wounds of Mother Earth and lacking the vision to look outwards to the endless resources and opportunities in space. These perceived differences are superficial. Environmentalists and space explorers actually share the same over-arching goal – the sustainable use of the environment around us; they just differ in the location they focus on.”

In this book excerpt, Cockell explains why humanity has only a brief period of time – out of the incredibly long history of life on our planet -- to set aside such superficial differences and prepare for a secure future on Earth and in space.


Excerpted from, “Space on Earth: Saving Our World by Seeking Others” by Charles S. Cockell. Copyright 2006. Reprinted with permission.

“Four and a half billion years ago, from the swirls of gas and material of the early Solar System, the Earth took shape. The origins of our world and the life on it are so remarkable that they take priority in religious texts as well as scientific ones. But the facts are as extraordinary as the fables. Soon after the Earth was formed – about seven hundred million years after – there is life in the fossil record.

During its flight, the Galileo spacecraft returned images of the Earth and moon. The separate images were combined to generate this view.
Credit: NASA
The tell-tale chemical signatures of life soon give way to hard evidence in the form of micro-fossils, the preserved remains of Earth’s earliest biosphere. The emergence of these microorganisms ushered in profound environmental changes. Cycles of carbon, iron, sulphur and many other elements were influenced and, in some cases, dominated by life.

It was only six hundred million years ago that complex multi-cellular life evolved and took hold in the sea. Only during the last two million of those do we appear on the stage, and only during the last forty thousand of those four and a half billion years of evolution do we start farming, painting caves, and building spaceships.

Environmental change has happened many times as these various stages of evolution emerged and changed the conditions of Earth. The production of oxygen by microbial life, so extensive that it now takes up a fifth of the atmosphere, has been described as the greatest pollution event in the history of life on Earth. By contrast, we have increased the carbon dioxide concentrations in the atmosphere by about 50% over the last two hundred years. In other words, massive environmental changes have occurred in the past and they have happened at the hands of unintelligent life.

Despite these changes, the Earth has remained habitable to life since its emergence, largely because of where we happen to be. Our place in the Solar System is the ‘habitable zone’, the region where liquid water is stable. Water is one of the most fundamental requirements for life. Without it there is no life as we know it. The environmental changes that have occurred in the past and which will occur in the future take place within the general context of astronomical location that is conducive to life, at least for the next one or two billion years, whatever the details of that life may be.

The habitable zone is the most basic concept of ‘habitability’. As well as being habitable, the Earth must also be conducive to our existence and our society. This means that temperatures must fall within defined limits that are much narrower than those for the stability of liquid water. We must have a breathable atmosphere, clean water and enough food. Seen from this perspective, environmental concern is just about a specialized subset of the habitable zone, about maintaining the Earth as an oasis for life, and in the process hopefully maintaining it as an oasis for humans. It is not surprising that as we go about maintaining the habitability of Earth and our spaceships, many connections will start to emerge between them.

Charles Cockell and Vladimir Pletser install dosimeters under gravel rocks, Devon Island, Canada, July 2001.
Credit: ESA

At the moment, these links are not developed to their full potential. The reasons for this are mainly historical, but also because very few of us go into space. As yet, not a single human individual lives permanently on the space frontier. At the time of writing, less than 600 individuals have been into space out of the many billions of humans that have ever lived. Small wonder that the idea of environmentalism and space settlement are one and the same goal is difficult to comprehend. Small wonder that environmentalists find space exploration distracting and irrelevant and those that explore space cannot see the role of environmentalism in their exclusive endeavor.

As space becomes accessible to many more people, creating places where people will be born, live and die, perhaps even without visiting the Earth, the links will become more obvious and widespread.

Our opportunity to build this bridge is not open-ended. Once humanity finds a way, perhaps driven by private enterprise, to access space, a new independent branch of society will become established there – it will rapidly become remote and separated from earthly concerns. Similarly, solving many environmental problems is now possible because we live in an affluent, resource-rich world with access to the means to address the diverse challenges. Leave it too long and space explorers will have built a community no longer concerned for Earth; environmentalists will be struggling in a world that is becoming poorer. The fusion of environmentalism and space settlement is a unique opportunity in the emerging history of humankind: one that is now, for a relatively brief period, available for us to grasp.

One day the idea of environmentalism being only about looking after life on Earth and the idea of space exploration being only about moving off Earth will seem bizarre to a generation of humans that is taught in school about life on Earth and in the many other colonized locations in space. To them, environmentalism will be about looking after life all over the Solar System, and space settlement will include the exploration and study of Earth amongst many other planets.”

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