Peter D. Ward – författare

In November 12, 2002, Dr. John Chambers of the NASA Ames Research Center gave a seminar to the Astrobiology Group at the University of Washington. The audience of about 100 listened with rapt attention as Chambers described results from a computer study of how planetary systems form. The goal of his research was to answer a deceptively simple question: How often would newly forming planetary systems produce Earth-like planets, given a star the size of our own sun? By “Earth-like” Chambers meant a rocky planet with water on its surface, orbiting within a star’s “habitable zone. ” This not-too-hot and not-too-cold inner region, relatively close to the star, supports the presence of liquid water on a planet surface for hundreds of million of years—the time-span probably necessary for the evolution of life. To answer the question of just how many Earth-like planets might be spawned in such a planetary system, Chambers had spent thousands of hours running highly sophisticated modeling programs through arrays of powerful computers. The results presented at the meeting were startling. The simulations showed that rocky planets orbiting at the “right” distances from the central star are easily formed, but they can end up with a wide range of water content. Earth seems to be quite a gem—a rocky planet where not only can liquid water exist for long periods of time, but where water can be found as a heathy oceanful—not too little and not too much. Our planet seems to reside in a benign region of the Galaxy, where comet and asteroid bombardment is tolerable and habitable-zone planets can commonly grow to Earth size. Such real estate in our galaxy—perhaps in any galaxy—is prime for life. And rare as well.

In November 12, 2002, Dr. John Chambers of the NASA Ames Research Center gave a seminar to the Astrobiology Group at the University of Washington. The audience of about 100 listened with rapt attention as Chambers described results from a computer study of how planetary systems form. The goal of his research was to answer a deceptively simple question: How often would newly forming planetary systems produce Earth-like planets, given a star the size of our own sun? By “Earth-like” Chambers meant a rocky planet with water on its surface, orbiting within a star’s “habitable zone. ” This not-too-hot and not-too-cold inner region, relatively close to the star, supports the presence of liquid water on a planet surface for hundreds of million of years—the time-span probably necessary for the evolution of life. To answer the question of just how many Earth-like planets might be spawned in such a planetary system, Chambers had spent thousands of hours running highly sophisticated modeling programs through arrays of powerful computers. The results presented at the meeting were startling. The simulations showed that rocky planets orbiting at the “right” distances from the central star are easily formed, but they can end up with a wide range of water content. Earth seems to be quite a gem—a rocky planet where not only can liquid water exist for long periods of time, but where water can be found as a heathy oceanful—not too little and not too much. Our planet seems to reside in a benign region of the Galaxy, where comet and asteroid bombardment is tolerable and habitable-zone planets can commonly grow to Earth size. Such real estate in our galaxy—perhaps in any galaxy—is prime for life. And rare as well.

Just 12,000 years ago - at the height of the last Ice Age - saber-toothed tigers, giant ground sloths, camels, hippos and the great herds of proboscideans: giant mastodons and mammoths, extinct relatives of the elephant, roamed the land where skyscrapers now stand. Why are these splendid creatures no longer with us? This compelling book explores the reasons for these extinctions and provides a tour of mass extinctions throughout earth's history, including the great comet crash that killed off the dinosaurs. Brilliantly written, The Call of Distant Mammoths is an engaging exploration of the history of life and the importance of humanity as an evolutionary force.

I n modem times, science has brought the past-and so many of its creatures-back to life via intellectual inquiry, application of the scientific method, and some extraordinary technology that has recently been devel­ oped. The wonder of the process is that such a rich and vivid understanding of the deep past has been generated from such scanty evidence: broken bones, lithified shells, fossil leaves, and even simple layered rocks. The sci­ entists who have contributed to this work have woven rich tapestries of an­ cient times, and their weaving, which is an adventure in itself, is the subject of this book. It is as if true time machines existed, enabling us to retreat through time's mists into the past, to examine the then-living as though liv­ ing still, to visit ancient worlds and reconstruct the lives their denizens led. vii TIME MA[HINES The past tantalizes us; it is part of our nature to seek clues about an­ cient times and our origins. Yet the past is far more than just some moment in time. In our own lives, for instance, it is also place, people (and other liv­ ing things), and history. Take the first day of school: the desks and posters, the windows and chalkboards, the people who left us there, the people we met. So, too, for paleontologists and archeologists is the deep past a conver­ gence of time, place, inhabitants, and their history or biological interactions.

Just 12,000 years ago - at the height of the last Ice Age - saber-toothed tigers, giant ground sloths, camels, hippos and the great herds of proboscideans: giant mastodons and mammoths, extinct relatives of the elephant, roamed the land where skyscrapers now stand. Why are these splendid creatures no longer with us? This compelling book explores the reasons for these extinctions and provides a tour of mass extinctions throughout earth's history, including the great comet crash that killed off the dinosaurs. Brilliantly written, The Call of Distant Mammoths is an engaging exploration of the history of life and the importance of humanity as an evolutionary force.

I n modem times, science has brought the past-and so many of its creatures-back to life via intellectual inquiry, application of the scientific method, and some extraordinary technology that has recently been devel­ oped. The wonder of the process is that such a rich and vivid understanding of the deep past has been generated from such scanty evidence: broken bones, lithified shells, fossil leaves, and even simple layered rocks. The sci­ entists who have contributed to this work have woven rich tapestries of an­ cient times, and their weaving, which is an adventure in itself, is the subject of this book. It is as if true time machines existed, enabling us to retreat through time''s mists into the past, to examine the then-living as though liv­ ing still, to visit ancient worlds and reconstruct the lives their denizens led. vii TIME MA[HINES The past tantalizes us; it is part of our nature to seek clues about an­ cient times and our origins. Yet the past is far more than just some moment in time. In our own lives, for instance, it is also place, people (and other liv­ ing things), and history. Take the first day of school: the desks and posters, the windows and chalkboards, the people who left us there, the people we met. So, too, for paleontologists and archeologists is the deep past a conver­ gence of time, place, inhabitants, and their history or biological interactions.

Just 12,000 years ago - at the height of the last Ice Age - saber-toothed tigers, giant ground sloths, camels, hippos and the great herds of proboscideans: giant mastodons and mammoths, extinct relatives of the elephant, roamed the land where skyscrapers now stand. Why are these splendid creatures no longer with us? This compelling book explores the reasons for these extinctions and provides a tour of mass extinctions throughout earth''s history, including the great comet crash that killed off the dinosaurs. Brilliantly written, The Call of Distant Mammoths is an engaging exploration of the history of life and the importance of humanity as an evolutionary force.

I n modem times, science has brought the past-and so many of its creatures-back to life via intellectual inquiry, application of the scientific method, and some extraordinary technology that has recently been devel­ oped. The wonder of the process is that such a rich and vivid understanding of the deep past has been generated from such scanty evidence: broken bones, lithified shells, fossil leaves, and even simple layered rocks. The sci­ entists who have contributed to this work have woven rich tapestries of an­ cient times, and their weaving, which is an adventure in itself, is the subject of this book. It is as if true time machines existed, enabling us to retreat through time's mists into the past, to examine the then-living as though liv­ ing still, to visit ancient worlds and reconstruct the lives their denizens led. vii TIME MA[HINES The past tantalizes us; it is part of our nature to seek clues about an­ cient times and our origins. Yet the past is far more than just some moment in time. In our own lives, for instance, it is also place, people (and other liv­ ing things), and history. Take the first day of school: the desks and posters, the windows and chalkboards, the people who left us there, the people we met. So, too, for paleontologists and archeologists is the deep past a conver­ gence of time, place, inhabitants, and their history or biological interactions.

Sind wir allein im Universum? Auf diese Frage geben der Geologe Peter D. Ward und der Astrobiologe Donald Brownlee überraschende Antworten. Sie widersprechen der allgemeinen Annahme, dass höher entwickeltes Leben außerhalb der Erde existiert, vielleicht sogar weit verbreitet ist. Auf der Suche nach Leben im Universum nehmen sie den Leser mit auf eine spannende Reise von den heißen vulkanischen Quellen des Ozeanbodens bis zu dem frostigen Antlitz von Europa, dem Jupiter-Mond. Dabei lernt der Leser, dass niedrig entwickeltes Leben vielleicht weiter verbreitet ist, als bisher angenommen, die Entstehung höher entwickelten Lebens aber zu komplex ist, um außerhalb der Erde stattfinden zu können. Ein faszinierendes, erfrischend geschriebenes Buch, das auf dem neuesten Stand der Wissenschaft beruht.