100-C 25-C 50-C 75-C C+M 50-C+M C+Y 50-C+Y M+Y 50-M+Y 100-M 25-M 50-M 75-M 100-Y 25-Y 50-Y 75-Y 100-K 25-K 25-19-19 50-K50-40-40 75-K 75-64-Foreword
The solar system has become humankind’s new backyard. It
is the playground of robotic planetary spacecraft that have
surveyed just about every corner of this vast expanse in
space. Nowadays, every schoolchild knows what even the
farthest planets look like. Fifty years ago, these places could
only be imagined, and traveling to them was the realm of
fiction. In just this short time in the long history of the
human species we have leapt off the surface of our home
planet and sent robotic extensions of our eyes, ears, noses,
arms, and legs to the far reaches of the solar system and
beyond.
In the early days of the 20th century, we were using air-
planes to extend our reach to the last unexplored surface
regions of our own planet. Now 100 years later, at the begin-
ning of the 21st century, we are using spacecraft to extend
our reach from the innermost planet Mercury to the out-
most planet Neptune, and we have a spacecraft on the way
to Pluto and the Kuiper Belt. Today, there are telescopes
beyond imagination 100 or even 50 years ago that can im-
age Pluto and detect planets around other stars! Now, Sol’s
planets can say “we are not alone”; there are objects just like
us elsewhere in the universe. As humanity’s space technol-
ogy improves, perhaps in the next 100 years or so human
beings also may be able to say “we are not alone.”
When I was a kid 50 years ago, I was thrilled by the
paintings of Chesley Bonestell and others who put their
imagination on canvas to show us what it might be like “out
there.” Werner Von Braun’sCollier’smagazine articles of
1952–1954 superbly illustrated how we would go to the
Moon and Mars using new rocket technologies. Reading
those fabulous articles crystallized thoughts in my young
mind about what to do with my life. I wanted to be part of
the adventure to find out what these places were like. Not
so long after theCollier’sarticles appeared, we did go to the
Moon, and pretty much as illustrated, although perhaps not
in such a grand manner. We have not sent humans to Mars—
at least we haven’t yet—but we have sent our robots to Mars
and to just about every other place in the solar system as
well.
This book is filled with the knowledge about our solar
system that resulted from all this exploration, whether by
spacecraft or by telescopes both in space and earth-bound.
It could not have been written 50 years ago as almost ev-
erything in this Encyclopedia was unknown back then. All
of this new knowledge is based on discoveries made in the
interim by scientist-explorers who have followed their in-
born human imperative to explore and to understand. Many
old mysteries, misunderstandings, and fears that existed
50 years ago about what lay beyond the Earth have been
eliminated.
We now know the major features of the landscape in
our cosmic backyard and can look forward to the adven-
ture, excitement, and new knowledge that will result from
more in-depth exploration by today’s spacecraft, such as
those actually exploring the surface of these faraway places,
including theHuygens Titanlander and theMars Explo-
rationrovers, doing things that were unimaginable before
the Space Age began.
TheEncyclopedia of the Solar Systemis filled with im-
ages, illustrations, and charts to aid in understanding. Every
object in the solar system is covered by at least one chap-
ter. Other chapters are devoted to the relationships among
the objects in the solar system and with the galaxy beyond.
The processes that operate on solar system objects, in their
atmospheres, on their surfaces, in their interiors, and inter-
actions with space itself are all described in detail. There are
chapters on how we explore and learn about the solar system
and about the investigations used to make new discoveries.
And there are chapters on the history of solar system explo-
ration and the missions that have carried out this enterprise.
All written by an international set of world-class scientists
using rigorous yet easy-to-understand prose.
Everything you want to know about the solar system is
here. This is your highway to the solar system. It is as much
fun exploring this Encyclopedia as all the exploration it took
to get the information that it contains. Let your fingers
be the spacecraft as you thumb through this book visiting
all the planets, moons and other small objects in the solar