Foreword
Mountains in the Sky
Comets Demystified, Asteroids Discovered
In the two centuries following Luther's passing, however, a number of pioneering astronomers demonstrated that comets are indeed natural, rather than supernatural, bodies. Moreover, these scientists showed, comets orbit the sun.
How Asteroids and Comets Formed
Up until about the middle of the twentieth century, astronomers still possessed an imperfect notion of how and where asteroids and comets originally formed. The theory that asteroids were the remnants of the explosion of an ancient planet still prevailed.
Vital Statistics of Asteroids and Comets
In this brief description of a comet floating in the distant Oort Cloud, Levy makes reference to the object's composition, its size, and its orbit, three of the four major vital statistics, so to speak, of comets. The other is the shape of such bodies.
Voyages to the Comets and Asteroids
Until the 1980s, most theories about the composition and other physical characteristics of asteroids and comets could not be verified because no one had ever seen one of these bodies up close. Astronomers who studied them had to rely on images taken by ground-based telescopes.
How Humans Will Mine Asteroids and Comets
Not surprisingly, drunk miners, gamblers, and painted women were not part of the vision of the scientists who began discussing asteroid mining in the 1970s. The technological advances made during the U.S.
When Comets and Asteroids Strike Earth
Mining some of the near-Earth asteroids will exploit the considerable constructive potential of these cosmic bodies. However, many of the NEAs have a darker, more destructive potential as well.