When I was young, I used to look up into the sky and see airplanes. Later, when I flew those airplanes, I realized I still hadn't gotten very high, that I couldn't go wherever I could see. I kept trying and I did get as far as the Moon. To Neil Armstrong, Buzz Al-drin, and me, that seemed a very long trip, but compared to reaching the nearest star it was like moving past a dozen grains of sand on a beach. The Moon is about 385,000 kilometers from Earth, while the nearest star, Proxima Centauri, is 40 trillion kilometers away. Now, back here on Earth with a better appreciation of distances, I borrow the eyes of astronomers to show me those places I will never visit. This beautiful book will help you to do that.
Throughout history, the genius of astronomers has been their ability to let their minds roam to the far reaches of the Universe while their bodies were trapped on Earth. Kepler, tracing the planets in their orbits; Einstein, seeing the Universe emerge from his chalkboard-they have freed our minds if not our bodies.
And perhaps our bodies will not be far be-hind. Rockets have propelled astronauts to the Moon and fired Pioneer spacecraft completely out of the Solar System. It is now technically possible for people to visit Mars, approximately nine months away.
The other planets are almost within our grasp and the moons of Jupiter and Saturn may be the unrealized gems of our Solar System. The cameras of the Voyager spacecraft have transformed Jupiter's moons from mere pinpoints of light in a telescope into intriguing, colorful spheres. Io...
Europa ... Ganymede ... Callisto. Even A spectacular night launch of Apollo 17 crowns the mission series that landed 12 U.S. astronauts on the Moon.
the sound of their names excites me. More enticing still is the prospect of what Voyager will tell us about Saturn. We already know that one of Saturn's moons, Titan, is surrounded by a thick atmosphere. It is my favorite candidate for human exploration.
Beyond Pluto, we have to admit that the distances seem to be too much for us, at least if we regard the velocity of light as the universal speed limit. However, not too many years ago, experts believed we would never break the sound "barrier." Right now, Einstein's theories seem to deny us the stars. Perhaps someday we can discover how to disembody humans in one place and recreate them elsewhere, to circumvent Einstein's barrier, and to roam the Uni-verse, seeking our peers or our superiors.
The more we see of other planets, the better this one looks. When I traveled to the Moon, it wasn't my proximity to that battered rockpile I remember so vividly, but rather what I saw when I looked back at my fragile home- a glistening, inviting beacon, delicate blue and white, a tiny outpost suspended in the black infinity.
Earth is to be treasured and nurtured, something precious that must endure.
The next two decades should be the most productive years astronomers have ever known. With space telescopes we will accumulate more information about the Universe than we have since humans began to study the heavens. May we be intelligent enough to comprehend it and sensible enough to use it to solve some of the pressing problems of our unique home.