by Mark R. Whittington
October 12, 2005
Terraforming means "to make Earth-like."
It is a technique that many
scientists believe could be the key to settling the high frontier of
space. But transforming a planet, such as Mars, to make its
environment more like that of Earth, a new world for humankind can
The dream of actually building settlements on other worlds is as old
as the space age. While hitherto, all voyages into space have been
temporary, the idea of space settlements implies people going to
live and work in space for the rest of their lives, much as people
hundreds of years ago voyaged to the Americas, leaving their old
lives behind, and building new ones in a new continent.
The problem with space settlements in the near term is that there
aren’t any places in the solar system where people can live without
a technologically advanced life support infrastructure. People
proposing to live on, say, the Moon or Mars would have to bring or
extract their own oxygen and water, as well as grow food and produce
There is no other place in our solar system, besides Earth,
where people can live out of doors.
What is Terraforming?
Terraforming is a concept that scientists have envisioned that could
bring dead worlds to life, so that people might more easily live on
Terraforming literally means to “make Earth-like”. The idea is
to change the environment of another planet to make it suitable for
human habitation using various technological techniques.
Candidates for Terraforming
Four worlds are at about the right size and mass to be candidates
These worlds are:
But Europa and Titan are too
far from the sun and are therefore too cold. Venus is too close to
the sun and has an incredibly thick atmosphere, and is therefore too
hot, with an average temperature of about 900 degrees Fahrenheit.
That leaves Mars.
At first glance,
Mars seems to be a poor candidate for a new world
for humanity as well. Its thin atmosphere is almost entirely made up
of carbon dioxide. The average surface temperature of Mars is about
minus 81 degrees Fahrenheit, with extremes ranging from plus 75
degrees to minus 100 degrees.
There are some characteristics of Mars that make it more Earth-like.
It’s rotational rate is almost exactly that of Earth’s, just over
twenty four hours. It has a axial tilt of 24 degrees as opposed to
that of Earth at 23.5 degrees. While Mars has one third the gravity
of Earth and is half again as far from the sun as Earth, it is close
enough to experience seasons.
What’s more, Mars has all the elements that are necessary for
sustaining life. There is water in the form of ice at the poles and
perhaps, according to the findings of NASA probes, underground. The
carbon dioxide atmosphere contains both carbon and oxygen.
also a small amount of nitrogen in the Martian atmosphere.
Based on the discoveries of probes like Spirit and Opportunity,
scientists have concluded that Mars was more Earth-like billions of
years ago. There was almost certainly a thicker, more oxygen rich
atmosphere. There was running water in the form of rivers and even
small oceans. There might even have been life of some sort, though
signs of that have yet to have been uncovered.
Given these facts, Mars becomes a prime candidate for transformation
into a smaller, sister of Earth. It would be the most challenging
project in human history, taking several decades or several
millennia, depending on whom one asks.
How to Terraform Mars
NASA’s Chris McKay and Mars visionary Robert Zubrin have suggested
that there are three possible ways to terraform Mars.
The first is to construct giant mirrors, with diameters in excess of
two hundred miles, to focus the sun’s energy on Mars, to cook out
frozen carbon dioxide at the Martian poles and in the Martian
surface to thicken the Martian atmosphere.
The second is to
artificially produce a greenhouse effect by building plants on Mars
that would produce chlorofluorocarbons or CFCs and release them into
The third and most drastic method is to smash
ammonia rich asteroids onto Mars, releasing a great deal of energy,
melting trillions of tons of water and raising the temperature of
Mars to a livable level in a matter of decades.
Because using mirrors alone might be insufficient to trigger a
Martian greenhouse effect and using ammonia rich asteroids would be
the equivalent of bombing Mars with 70,000 megaton explosions, McKay
and Zubrin conclude that using greenhouse gas producing plants on
Mars, perhaps along with mirrors, is the better solution for
Bringing Mars to Life
The first stage for terraforming Mars would be to create nuclear
powered greenhouse plants that would extract greenhouse gasses from
the Martian soil and release it into the atmosphere.
McKay and Zubrin believe that this would require a large industrial
infrastructure on Mars supported by several thousand people and with
a budget of several hundred billion dollars.
As the temperature of Mars rises, the atmosphere thickens, the
radiation level on the Martian surface decreases, and water begins
to flow, genetically engineered plants can be introduced to begin
creating an oxygen rich atmosphere.
McKay and Zubrin estimate, given
current technology, that this method would produce a Mars upon which
people can go outdoors unprotected in about nine hundred years. Long
before that time, people could go outside on Mars wearing nothing
more complicated than breathing gear.
Greater power sources - say fusion derived - for the greenhouse plants
and better engineered plants could compress that time from centuries
to decades. Developing such technology in the 21st Century would not
be inconceivable, given the history of technological advances just
in the past century.
Terraforming in Science Fiction
Terraforming, especially of Mars, has been a familiar subject in
One of the first instances was in the novel,
Sands of Mars, by Arthur C. Clarke, published over fifty years ago.
More recently, Kim Stanley Robinson explored the technological
feasibility and the sociological implications of terraforming Mars
in his Mars trilogy, which includes Red Mars, Blue Mars, and
A New World for Humanity
If one accepts the most optimistic schedule for terraforming
then it could be that by the end of this century, a “blue Mars”,
teeming with life, with breathable air, and free flowing water will
be a reality.
Such a world could be, for our grandchildren and great
grandchildren, a new frontier, much as America was for our
ancestors. It could be a place for people to build new lives and
experiment with new ways of ordering society.
Frontiers test and
strengthen the people willing to go to them and make them their
Finally, building a new world on Mars, and making it a new
home for restless people, would help ensure the long time survival
of the human species. A multiplanet civilization cannot be destroyed
by some cataclysm, either natural or manmade.
In an era of great
anxiety about the long term prospects of the human race, that is a
promise that would be worth a lot to fulfill.