This accessible and entertaining biography chronicles the life and triumphs of astronomer Jan Hendrik Oort, who helped lay the foundations of modern astronomy in the 20th century. The book puts into context some of Oort's most significant achievements, including his discovery that the Milky Way rotates, as well as his famous hypothesis that our Solar System is surrounded by a reservoir of comets - now simply known as the Oort Cloud. Written by Oort's former student, this fascinating story also delves into Oort's pivotal role in the foundation of major astronomical facilities, including radio telescopes in the Netherlands and the European Southern Observatory (ESO), which now operates the most successful astronomical observatories in the world. The book draws extensively on new archival research through the Oort Archives, along with personal reminiscences by Oort's son and astronomer-grandson, to paint a more detailed picture of Oort's life not just as an astronomer, but also as a husband, father, and citizen. The strong public interest in comets triggered by the Rosetta mission to comet 67P/Churyumov-Gerasimenko and the recently discovered interstellar comet in the Solar System make this book particularly timely.

Introduction.- Boarding School and University.- Astronomy Around 1875.- Astronomer and Professor.- Almost Half a Million Stars.- Laboratory and Statistical Astronomy.- Star Streams.- In the mean time in Groningen.- Mount Wilson.- Statistics and other matters.- First Attempt: the Kapetyn Universe.- Coda.

Jacobus C. Kapteyn (1851-1922) was a Dutch astronomer who contributed heavily to major catalogs of star positions, such as the Cape Photographic Durchmusterung and the Harvard-Groningen Durchmusterung, and arranged extensive international collaboration through his Plan of Selected Areas. He contributed to the establishment of statistical astronomy and structure and dynamics of the Sidereal System. All aspects of Kapteyn's life are discussed, from his birth in Barneveld, the Netherlands, to his death in Amsterdam, and his entire resume of scientific achievements in between. Kapteyn had some conflicts with others in his field, especially after the world became divided on how to handle scientific contributions from Germany post-World War I. Both Kapteyn's struggles and achievements are written against the backdrop of both the historical context of the world at that time as well as the scientific one.

This book is the first thorough and overdue biography of one of the giants of science in the twentieth century, Jan Hendrik Oort. His fundamental contributions had a lasting effect on the development of our insight and a profound influence on the international organization and cooperation in his area of science and on the efforts and contribution of his native country. This book aims at describing Oort's life and works in the context of the development of his branch of science and as a tribute to a great scientist in a broader sense. The astronomer Jan Hendrik Oort from the Netherlands was founder of studies of the structure and dynamics of the Milky Way Galaxy, initiator of radioastronomy and the European Southern Observatory, and an important contributor to many areas of astronomy, from the study of comets to the universe on the largest scales.

This accessible and entertaining biography chronicles the life and triumphs of astronomer Jan Hendrik Oort, who helped lay the foundations of modern astronomy in the 20th century. The book puts into context some of Oort's most significant achievements, including his discovery that the Milky Way rotates, as well as his famous hypothesis that our Solar System is surrounded by a reservoir of comets - now simply known as the Oort Cloud. Written by Oort's former student, this fascinating story also delves into Oort's pivotal role in the foundation of major astronomical facilities, including radio telescopes in the Netherlands and the European Southern Observatory (ESO), which now operates the most successful astronomical observatories in the world. The book draws extensively on new archival research through the Oort Archives, along with personal reminiscences by Oort's son and astronomer-grandson, to paint a more detailed picture of Oort's life not just as an astronomer, but also as a husband, father, and citizen. The strong public interest in comets triggered by the Rosetta mission to comet 67P/Churyumov-Gerasimenko and the recently discovered interstellar comet in the Solar System make this book particularly timely.

Introduction.- Boarding School and University.- Astronomy Around 1875.- Astronomer and Professor.- Almost Half a Million Stars.- Laboratory and Statistical Astronomy.- Star Streams.- In the mean time in Groningen.- Mount Wilson.- Statistics and other matters.- First Attempt: the Kapetyn Universe.- Coda.

This book is the first thorough and overdue biography of one of the giants of science in the twentieth century, Jan Hendrik Oort. His fundamental contributions had a lasting effect on the development of our insight and a profound influence on the international organization and cooperation in his area of science and on the efforts and contribution of his native country. This book aims at describing Oort's life and works in the context of the development of his branch of science and as a tribute to a great scientist in a broader sense. The astronomer Jan Hendrik Oort from the Netherlands was founder of studies of the structure and dynamics of the Milky Way Galaxy, initiator of radioastronomy and the European Southern Observatory, and an important contributor to many areas of astronomy, from the study of comets to the universe on the largest scales.