About the Author
The best-selling author of "Nightwatch", "Exploring the Night Sky", "The Backyard Astronomer's Guide", "Exploring the Sky by Day", and "From Big Bang to Planet X", Terence Dickinson has received many national and international science awards including the New York Academy of Sciences Book of the Year Award and the Royal Canadian Institute's Sandford Fleming Medal. More than one million of his previous books are in print in three languages.
Excerpt. © Reprinted by permission. All rights reserved.
Are We Alone?
What will they look like? Extraterrestrials, that is. We've seen lots of aliens on television and in the movies -- everything from Mr. Spock to talking rocks.
Some of those television and movie aliens look exactly like us. Some are just a bit different, with weird skin color, pointy ears or distorted facial features. Others are bizarre, like the giant walrus-like Jabba the Hutt in the Star Wars movie Return of the Jedi.
But have you ever wondered whether these aliens actually make sense? What do they eat? What is their home planet like? What type of air do they breathe?
In this book, we venture beyond the aliens we know from television and the movies and try to be a little more scientific in our approach as we explore what extraterrestrials might be like -- if they exist. We examine the possibilities for life as we know it and travel into the shadowy realm of life as we don't know it. We have tried to blend science and imagination to depict life on other planets. It's a voyage into the possible, if not the probably.
One thing we do know when we look around us at the other planets in our own solar system is that we don't find worlds with surface conditions anything like the Earth's. Not a drop of water exists on our moon. The nearest planet, Venus, has a surface hot enough to melt lead, even at its poles. Our other nearby planetary neighbor, Mars -- the planet most like Earth -- is a frigid desert world. Mars and Venus are the planets where astronomers expected to find conditions similar to those on Earth.
In fact, the more we learn about other worlds, the more we realize that an enormous variety of conditions exists out there. Although only a small fraction of those environments could support life as we know it, the universe, as we shall see, is a very big place.
Imagine that each star in the known universe is represented by a single grain of sand. A thimble would hold all the stars visible on a clear, dark summer night. A large construction wheelbarrow would contain the Milky Way, the galaxy in which our sun resides. But to demonstrate the immense numbers of stars in the universe, we need a freight train with hopper cars filled with sand. As the train begins to speed by us at a level crossing, we count the cars while we wait. The cars roar past, one per second. We would have to keep count 24 hours a day for three years before the universe train had completed its pass.
If only one star in a billion is parent to a planet with life, then at least one trillion planets in the universe harbor living matter. Suppose that during the history of the Milky Way Galaxy, a few hundred other intelligent technological civilizations arose on places much like Earth. What would these civilizations be like? It's a powerful question -- one that carries the mind to limitless speculation.
--This text refers to an out of print or unavailable edition of this title.
