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Comet
WHAT ARE THESE GRACEFUL VISITORS TO OUR SKIES? WE NOW KNOW THAT THEY BRING BOTH LIFE AND DEATH AND TEACH US ABOUT OUR ORIGINS.
Comet begins with a breathtaking journey through space astride a comet. Pulitzer Prize-winning astronomer Carl Sagan, author of Cosmos and Contact, and writer Ann Druyan explore the origin, nature, and future of comets, and the exotic myths and portents attached to them. The authors show how comets have spurred some of the great discoveries in the history of science and raise intriguing questions about these brilliant visitors from the interstellar dark.
Were the fates of the dinosaurs and the origins of humans tied to the wanderings of a comet? Are comets the building blocks from which worlds are formed?
Lavishly illustrated with photographs and specially commissioned full-color paintings, Comet is an enthralling adventure, indispensable for anyone who has ever gazed up at the heavens and wondered why.
"SIMPLY THE BEST."
*The Times of London
"FASCINATING, EVOCATIVE, INSPIRING."
*The Washington Post
"COMET HUMANIZES SCIENCE. A BEAUTIFUL, INTERESTING BOOK."
*United Press International
"MASTERFUL . . . SCIENCE, POETRY, AND IMAGINATION."
*The Atlanta Journal & Constitution
Comet begins with a breathtaking journey through space astride a comet. Pulitzer Prize-winning astronomer Carl Sagan, author of Cosmos and Contact, and writer Ann Druyan explore the origin, nature, and future of comets, and the exotic myths and portents attached to them. The authors show how comets have spurred some of the great discoveries in the history of science and raise intriguing questions about these brilliant visitors from the interstellar dark.
Were the fates of the dinosaurs and the origins of humans tied to the wanderings of a comet? Are comets the building blocks from which worlds are formed?
Lavishly illustrated with photographs and specially commissioned full-color paintings, Comet is an enthralling adventure, indispensable for anyone who has ever gazed up at the heavens and wondered why.
"SIMPLY THE BEST."
*The Times of London
"FASCINATING, EVOCATIVE, INSPIRING."
*The Washington Post
"COMET HUMANIZES SCIENCE. A BEAUTIFUL, INTERESTING BOOK."
*United Press International
"MASTERFUL . . . SCIENCE, POETRY, AND IMAGINATION."
*The Atlanta Journal & Constitution
13 pages, Audible Audio
First published November 12, 1985
94 people are currently reading
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About the author
Carl Sagan
170 books12.7k followersIn 1934, scientist Carl Sagan was born in Brooklyn, N.Y. After earning bachelor and master's degrees at Cornell, Sagan earned a double doctorate at the University of Chicago in 1960. He became professor of astronomy and space science and director of the Laboratory for Planetary Studies at Cornell University, and co-founder of the Planetary Society. A great popularizer of science, Sagan produced the PBS series, "Cosmos," which was Emmy and Peabody award-winning, and was watched by 500 million people in 60 countries. A book of the same title came out in 1980, and was on The New York Times bestseller list for 7 weeks. Sagan was author, co-author or editor of 20 books, including The Dragons of Eden (1977), which won a Pulitzer, Pale Blue Dot (1995) and The Demon-Haunted World: Science As a Candle in the Dark (1996), his hardest-hitting on religion. With his wife, Ann Druyan, he was co-producer of the popular motion picture, "Contact," which featured a feminist, atheist protagonist played by Jodie Foster (1997). The film came out after Sagan's death, following a 2-year struggle with a bone marrow disease. Sagan played a leading role in NASA's Mariner, Viking, Voyager, and Galileo expeditions to other planets. Ann Druyan, in the epilogue to Sagan's last book, Billions and Billions: Thoughts on Life and Death at the Brink of the Millennium (published posthumously in 1997), gives a moving account of Carl's last days: "Contrary to the fantasies of the fundamentalists, there was no deathbed conversion, no last minute refuge taken in a comforting vision of a heaven or an afterlife. For Carl, what mattered most was what was true, not merely what would make us feel better. Even at this moment when anyone would be forgiven for turning away from the reality of our situation, Carl was unflinching. As we looked deeply into each other's eyes, it was with a shared conviction that our wondrous life together was ending forever."
For his work, Dr. Sagan received the NASA medals for Exceptional Scientific Achievement and (twice) for Distinguished Public Service, as well as the NASA Apollo Achievement Award. Asteroid 2709 Sagan is named after him. He was also awarded the John F. Kennedy Astronautics Award of the American Astronautical Society, the Explorers Club 75th Anniversary Award, the Konstantin Tsiolkovsky Medal of the Soviet Cosmonauts Federation, and the Masursky Award of the American Astronomical Society, ("for his extraordinary contributions to the development of planetary science…As a scientist trained in both astronomy and biology, Dr. Sagan has made seminal contributions to the study of planetary atmospheres, planetary surfaces, the history of the Earth, and exobiology. Many of the most productive planetary scientists working today are his present and former students and associates").
He was also a recipient of the Public Welfare Medal, the highest award of the National Academy of Sciences.
Dr. Sagan was elected Chairman of the Division of Planetary Sciences of the American Astronomical Society, President of the Planetology Section of the American Geophysical Union, and Chairman of the Astronomy Section of the American Association for the Advancement of Science. For twelve years he was the editor-in-chief of Icarus, the leading professional journal devoted to planetary research. He was cofounder and President of the Planetary Society, a 100,000-member organization that is the largest space-interest group in the world; and Distinguished Visiting Scientist, Jet Propulsion Laboratory, California Institute of Technology.
In their posthumous award to Dr. Sagan of their highest honor, the National Science Foundation declared that his "research transformed planetary science… his gifts to mankind were infinite." D. 1996.
More: https://ffrf.org/news/day/dayitems/it...
For his work, Dr. Sagan received the NASA medals for Exceptional Scientific Achievement and (twice) for Distinguished Public Service, as well as the NASA Apollo Achievement Award. Asteroid 2709 Sagan is named after him. He was also awarded the John F. Kennedy Astronautics Award of the American Astronautical Society, the Explorers Club 75th Anniversary Award, the Konstantin Tsiolkovsky Medal of the Soviet Cosmonauts Federation, and the Masursky Award of the American Astronomical Society, ("for his extraordinary contributions to the development of planetary science…As a scientist trained in both astronomy and biology, Dr. Sagan has made seminal contributions to the study of planetary atmospheres, planetary surfaces, the history of the Earth, and exobiology. Many of the most productive planetary scientists working today are his present and former students and associates").
He was also a recipient of the Public Welfare Medal, the highest award of the National Academy of Sciences.
Dr. Sagan was elected Chairman of the Division of Planetary Sciences of the American Astronomical Society, President of the Planetology Section of the American Geophysical Union, and Chairman of the Astronomy Section of the American Association for the Advancement of Science. For twelve years he was the editor-in-chief of Icarus, the leading professional journal devoted to planetary research. He was cofounder and President of the Planetary Society, a 100,000-member organization that is the largest space-interest group in the world; and Distinguished Visiting Scientist, Jet Propulsion Laboratory, California Institute of Technology.
In their posthumous award to Dr. Sagan of their highest honor, the National Science Foundation declared that his "research transformed planetary science… his gifts to mankind were infinite." D. 1996.
More: https://ffrf.org/news/day/dayitems/it...
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Displaying 1 - 30 of 61 reviews
December 18, 2018
Когато преди време в ръцете ми попадна романа „Контакт” от Карл Сейгън се огледах какво още има преведено у нас от този велик ум на астрономията и космологията. Връхлетя ме „Комета” (изд. „Изток-Запад”) – впечатляващ труд, който Сейгън пише в съавторство със съпругата си Ан Друян, на свой ред писател, продуцент и популяризатор на науката. Прочетете ревюто на "Книжни Криле": https://knijnikrile.wordpress.com/201...
April 30, 2019
Comet opens by taking the reader on a ride through the galaxy on a comet, experiencing everything that could have happened to the comet on its journey. Sagan and Druyan do a wonderful job telling the story of comets without having the reader feel as if they are sitting in a classroom....half bored. Yet, the reader is being told the story of these great traveling beauties that bring life and destruction through out the galaxy,
We're introduced to Edmond Halley, the man that discovered Halley's Comet. Halley was an English astronomer, geophysicist, mathematician, meteorologist, and physicist. He spent a great deal of his studies on the world of comets. Even with all of Halley's studies, he only began to scratch the surface of what makes up a coment.
We're introduced to Edmond Halley, the man that discovered Halley's Comet. Halley was an English astronomer, geophysicist, mathematician, meteorologist, and physicist. He spent a great deal of his studies on the world of comets. Even with all of Halley's studies, he only began to scratch the surface of what makes up a coment.
September 7, 2017
Кометите – вестители от миналото, онова, истинското и милиардогодишното: http://knigolandia.info/book-review/k...
“Комета” е шеметно пътешествие, което едновременно се вглежда в далечното минало, когато се е формирала Слънчевата система в яростни сблъсъци и кошмарни катаклизми, и далеч отвъд орбитата на Плутон, където невидими се носят безброй замръзнали тела, останки от този период. Нарядко някоя от тях бива увлечена поради една или друга причина и се гмурва към Слънчевата система, където, ако имаме късмет, я виждаме в небето си, а ако нямаме… е, динозаврите са нямали.
Издателство "Изток-Запад"
http://knigolandia.info/book-review/k...
“Комета” е шеметно пътешествие, което едновременно се вглежда в далечното минало, когато се е формирала Слънчевата система в яростни сблъсъци и кошмарни катаклизми, и далеч отвъд орбитата на Плутон, където невидими се носят безброй замръзнали тела, останки от този период. Нарядко някоя от тях бива увлечена поради една или друга причина и се гмурва към Слънчевата система, където, ако имаме късмет, я виждаме в небето си, а ако нямаме… е, динозаврите са нямали.
Издателство "Изток-Запад"
http://knigolandia.info/book-review/k...
March 27, 2016
Being the seventh Carl Sagan's book I've read,"Comet" was a book co-written by, of course, the late Great Carl Sagan and Ann Druyan in 1985 before the return of the historical comet Halley. The book offers us a spectacular ride on the comet from its origins to the point when it gets close to the Sun and heads back to where it comes from. After that, nearly everything you might be curious or might not even imagine to ask about comets will lie on the pages; the histories, myths, the physical appearances, the compositions, impacts, and future influences of these wonderful visitors from the frozen interstellar darkness.
The authors' visions for the future advantages of comets and asteroids for our space exploration raise many intriguing questions to the readers and make them wish that governments would unite for the sake of science, knowledge and the survival of human civilization. Opportunity, money and technology to reach that goal are already within our grasp, but everything else is up to us to decide whether we would waste the money on war or invest them in exploration for our long term benefits.
"Comets may act as the creators, the preservers, and the destroyers of life on Earth," the authors argue, "A surviving dinosaur might have reason to mistrust them, but humans might more appropriately consider the comets in a favorable light—as bringers of the stuff of life to Earth, as ocean-builders, as the agency that removed the competition and made possible the success of our mammalian ancestors, as possible future outposts of our species, and as providers of a timely reminder about large explosions and the climate of the Earth." Comets and asteroids could be extract as raw materials so that we wouldn't need to send them from earth, which would cost hundreds of millions of dollars, they could provide fuels, water and many other organic materials, making the exploration more bearable and reachable.
Yes, the book was written 26 years ago. Despite being revised in 1997, many discoveries related to comets have been discovered and understood since then. Yet, the book cannot be devalued; it can be an informative companion to the study of comet in our modern day.
The authors' visions for the future advantages of comets and asteroids for our space exploration raise many intriguing questions to the readers and make them wish that governments would unite for the sake of science, knowledge and the survival of human civilization. Opportunity, money and technology to reach that goal are already within our grasp, but everything else is up to us to decide whether we would waste the money on war or invest them in exploration for our long term benefits.
"Comets may act as the creators, the preservers, and the destroyers of life on Earth," the authors argue, "A surviving dinosaur might have reason to mistrust them, but humans might more appropriately consider the comets in a favorable light—as bringers of the stuff of life to Earth, as ocean-builders, as the agency that removed the competition and made possible the success of our mammalian ancestors, as possible future outposts of our species, and as providers of a timely reminder about large explosions and the climate of the Earth." Comets and asteroids could be extract as raw materials so that we wouldn't need to send them from earth, which would cost hundreds of millions of dollars, they could provide fuels, water and many other organic materials, making the exploration more bearable and reachable.
Yes, the book was written 26 years ago. Despite being revised in 1997, many discoveries related to comets have been discovered and understood since then. Yet, the book cannot be devalued; it can be an informative companion to the study of comet in our modern day.
May 7, 2020
El Cometa es un libro totalmente necesario para quienes tenemos curiosidad por el Universo y sus orígenes, tales como Historia del Tiempo de Hawking, Cosmos del mismo Carl Sagan, entre otros que nos han enamorado con su maestría en divulgación. El Cometa examina 1) socialmente, 2) cronológicamente, 3) químicamente, 4) antropológicamente y 5) astrofísicamente la presencia de los cometas en el Universo, y su relación con el ser humano. La palabra antropología es clave, ya que Carl Sagan examina (como siempre lo hace) con detalles cómo la observación de estos "entes sobrenaturales" han impactado a la humanidad desde sus propios orígenes; como diversas culturas le han dado un significado a los cometas, en la China ancestral eran en su mayoría malos presagios, pero para algunos pueblos, la presencia de los cometas era un buen augurio.
Desconocía totalmente que la esvástica utilizada en el ejército nazi, es un símbolo que se ha encontrado en una gran cantidad de vestigios arqueológicos, desde tribus en África, Australia, China, en romanos, griegos e incluso etruscos, y no olvidar en antiguos pueblos del Extremo Oriente.
La composición química, tal y como es la presencia de clatratos que encierran materiales exóticos, va de la mano con la explicación de que la vida en la Tierra apareció mil millones de años después de la creación del Sistema Solar. Las sustancias que componen la materia orgánica, la misma que logró unificarse en ARN y posteriormente con mayor complejidad en ADN, están en su mayoría fuera de la tierra, por tanto, en un paralelismo con John Gribbin, es evidencia que los cometas, durante el gran bombardeo tardío, hayan aportado con moléculas que sean amigables para la vida.
¿Cómo no enamorarse de un libro así?
¿Cómo no prosternarse ante la cosmología y sus ciencias relativas?
Es una maravilla de libro, ya que incluso explora la vida de grandes contribuyentes al conocimiento de la astrofísica y de la astronomía, al igual que la percepción trágica característica de la Edad Oscura.
Carl Sagan siempre deslumbra, y este libro no es una excepción para quienes creemos saber tan solo un poquito de la mecánica del Universo.
Desconocía totalmente que la esvástica utilizada en el ejército nazi, es un símbolo que se ha encontrado en una gran cantidad de vestigios arqueológicos, desde tribus en África, Australia, China, en romanos, griegos e incluso etruscos, y no olvidar en antiguos pueblos del Extremo Oriente.
La composición química, tal y como es la presencia de clatratos que encierran materiales exóticos, va de la mano con la explicación de que la vida en la Tierra apareció mil millones de años después de la creación del Sistema Solar. Las sustancias que componen la materia orgánica, la misma que logró unificarse en ARN y posteriormente con mayor complejidad en ADN, están en su mayoría fuera de la tierra, por tanto, en un paralelismo con John Gribbin, es evidencia que los cometas, durante el gran bombardeo tardío, hayan aportado con moléculas que sean amigables para la vida.
¿Cómo no enamorarse de un libro así?
¿Cómo no prosternarse ante la cosmología y sus ciencias relativas?
Es una maravilla de libro, ya que incluso explora la vida de grandes contribuyentes al conocimiento de la astrofísica y de la astronomía, al igual que la percepción trágica característica de la Edad Oscura.
Carl Sagan siempre deslumbra, y este libro no es una excepción para quienes creemos saber tan solo un poquito de la mecánica del Universo.
May 19, 2019
The science fiction lover in me drives me to read the occasional popular science text such as A Brief History of Time or Comet by Sagan and Druyan. This is an excellent survey of our understanding of comets for the non-specialist. It opens with a long historiography of the ancient, medieval and early modern world’s view of comets as harbingers of disaster. Then moves into the scientists who evolved our current understanding of these fascinating celestial bodies. Halley and Newton stood out most strongly to me, but they were by no means the only ones. The book winds up with explorations of the probable impact (pun intended) of comets on the development of our planet and the life upon it. If you’ve any curiosity about any of these issues, you’re likely to greatly enjoy Comet.
If you liked this review, you can find more at www.gilbertstack.com/reviews.
If you liked this review, you can find more at www.gilbertstack.com/reviews.
October 10, 2020
This book starts with the quaint musings of ancient Chinese record keepers on the fortune brought by different shapes of comets.
It follows our evolution in thought about comets to the present day, where we recognize them as leftovers from the formation of the solar system. We see in them the building blocks of life. We credit them for the formation of Earth's oceans. Comets are a lot more than bad omens in the sky. Except for that one time 65 million years ago!
I love how much knowledge Sagan was able to connect seemingly effortlessly to these rare visitors.
It follows our evolution in thought about comets to the present day, where we recognize them as leftovers from the formation of the solar system. We see in them the building blocks of life. We credit them for the formation of Earth's oceans. Comets are a lot more than bad omens in the sky. Except for that one time 65 million years ago!
I love how much knowledge Sagan was able to connect seemingly effortlessly to these rare visitors.
September 15, 2018
Buku ini membahas segala sesuatu tentang salah satu benda langit yang disebut juga bintang berekor, komet. Mulai dari awal diketahui keberadaannya, sejarah, asal-usul proses pembentukannya, mitologi, dan sifat-sifatnya secara ilmiah, juga peran, persepsi dan perubahan pemahaman manusia terhadap komet. Ditulis dan pertama kali diterbitkan pada tahun 1985, sebagian besar bahasan pada buku ini masih cukup relevan untuk dibaca saat ini. Karena saya merasa tidak punya dasar dan pemahaman astronomi yang lebih mendalam 😀, saya tidak tahu persis bagian-bagian mana yang benar-benar sudah tidak relevan dengan perkembangan ilmu astronomi saat ini
Recommended to astronomy lover and Sagan fans!
Recommended to astronomy lover and Sagan fans!
February 26, 2021
I think this book is great if you're into comets. It talks about everything from scientific evidence and theories as well as as history as to whom started studying them, the meaning of the comets in different cultures and other cultural aspects. I didn't find particularly interesting because the theme of the book isn't very appealing to me. But again if you'd like to know more about comets, doing so with Sagan and Druyan's eloquence will do it for you
February 6, 2020
Comets
By Carl Sagan and Ann Druyan
- [ ] First Sagan book of the year. I am excited!
- [ ] Opens with taking a journey on a lonely comet traveling a million year’s from the distant Oort Cloud through the solar system around the sun and eventually colliding with Earth.
- [ ] A comet is a cold lonely thing. Flying through cold dark space. Mainly made of ice and possessing little gravity. It has no atmosphere and is a hunk of ice. They range in size but this was the size of a city if you include the tail.
- [ ] It moves based on the pull of gravity fields, as all objects on the universe do.
- [ ] The second chapter describes human’s relationship with comets through out history. Humans have been recording and observing comets for thousands of years. Since 3,000 BCE.
- [ ] In almost all cultures they have signs of death, destruction, catastrophe, and omens.
- [ ] The Chinese, Greeks, and Romans wrote about them.
- [ ] There is a notable comet in the sky roughly once every 10 years
- [ ] Edward Halley (1656 -1741): English scientist, Halley’s comet
- [ ] Comets move in elliptical orbits
- [ ] Was a contemporary and friend of Issac Newton
- [ ] Brilliant scientist that contributed to the study of many fields, astronomy in particular. He was the one that began to make predictions on the return of certain comets. He correctly predicted the return of comets that would come after his death.
- [ ] In a previous Sagan book he has a line about religion can not make accurate predictions but science can make accurate enough predictions about when certain planets will be in a certain place that they have been able to land rovers on those planets and have the Voyager Probes fly past multiple planets
- [ ] Jupiter and it’s gravity sweep up most large comets
- [ ] Halley did not discover Halley’s comet but it was named after him
- [ ] Comets have strange orbits that I want to look up
- [ ] There seems to be a section in every Sagan book that does not capture me/I tune out. The Halley section was it for this book
- [ ] Kant was mentioned
- [ ] The 1760’s was a big decade
- [ ] Long period comets: out to the Oort Cloud and with orbits greater than 200 years, they have orbits of thousands of years. Hale-Bopp is 2500 years
- [ ] Short period comets: Kuiper belt and less than 200 year orbit. Halley’s comet is 76 years
- [ ] The sun, planets, and other gravities have an effect on the orbit of comets and change their orbit
- [ ] Comets are made from the remnants of planets and the beginning of our solar system
- [ ] Comets and ice
- [ ] The chemical make up of comets
- [ ] Chemistry
- [ ] Lots of technical stuff about comets; composition, tail, movement
- [ ] A section about the history of the swastika and how it could actually be a comet
- [ ] The Oort Cloud
- [ ] Comet: primarily composed of ice and dust, contain long/short orbits, have a tail/nucleolus, larger than a meteor, often many kilometers in size
- [ ] Asteroid: the remnants of planets, composed of mineral and rock, typically live in the astroid belt, are not seen by the naked eye, don’t have a tail/nucleolus
- [ ] Meteor: a small piece of a comet or asteroid that breaks off and burns up in the atmosphere
- [ ] The origins of our solar system
- [ ] Cataclysms, extinctions, comets
- [ ] Again he mentions human’s negative impact on the planet and us being the cause of animal extinction. Also we are the ones that can stop it.
- [ ] We intercepted and took photos of comets in his life time, he talks about it. In the past ten years we have landed on a comet, collected samples, and they are being returned to Earth. Science and math are amazing.
- [ ] I always think of his line about theologians not being able to predict god but scientists can predict the timing and place of comets and planets to such a precise point that we can land rovers on them.
- [ ] Even when I am zoned out during this book I have an image of a comet hurtling through the lonely darkness of space. Although the solar system does not seem as lonely. Sagan has made me feel like it is smaller and a family. The opening chapters of placing me on a comet for millions of years, that image and feeling has stayed with me throughout the book.
- [ ] He talks about mining comets, living on comets, and traveling on comets
- [ ] Halley’s comet has been noted by civilizations across the planet since at least 200 BCE. It is a time capsule of our world. It has been recorded on animals skins and in clay tablets. It visits us once a life time. It is poetic.
- [ ] Sagan ends in a typical Sagan way. Reminding us of the importance of our planet, the fragility of our existence, the importance and absolute insignificance of our life on this tiny rock. We are floating in a infinite ocean of the cosmos. Sagan always hits with magic, wonder, and aww.
- [ ] Comets are really the only travelers of the cosmic ocean.
- [ ] Not the most engaging of his books but beautiful and timeless
By Carl Sagan and Ann Druyan
- [ ] First Sagan book of the year. I am excited!
- [ ] Opens with taking a journey on a lonely comet traveling a million year’s from the distant Oort Cloud through the solar system around the sun and eventually colliding with Earth.
- [ ] A comet is a cold lonely thing. Flying through cold dark space. Mainly made of ice and possessing little gravity. It has no atmosphere and is a hunk of ice. They range in size but this was the size of a city if you include the tail.
- [ ] It moves based on the pull of gravity fields, as all objects on the universe do.
- [ ] The second chapter describes human’s relationship with comets through out history. Humans have been recording and observing comets for thousands of years. Since 3,000 BCE.
- [ ] In almost all cultures they have signs of death, destruction, catastrophe, and omens.
- [ ] The Chinese, Greeks, and Romans wrote about them.
- [ ] There is a notable comet in the sky roughly once every 10 years
- [ ] Edward Halley (1656 -1741): English scientist, Halley’s comet
- [ ] Comets move in elliptical orbits
- [ ] Was a contemporary and friend of Issac Newton
- [ ] Brilliant scientist that contributed to the study of many fields, astronomy in particular. He was the one that began to make predictions on the return of certain comets. He correctly predicted the return of comets that would come after his death.
- [ ] In a previous Sagan book he has a line about religion can not make accurate predictions but science can make accurate enough predictions about when certain planets will be in a certain place that they have been able to land rovers on those planets and have the Voyager Probes fly past multiple planets
- [ ] Jupiter and it’s gravity sweep up most large comets
- [ ] Halley did not discover Halley’s comet but it was named after him
- [ ] Comets have strange orbits that I want to look up
- [ ] There seems to be a section in every Sagan book that does not capture me/I tune out. The Halley section was it for this book
- [ ] Kant was mentioned
- [ ] The 1760’s was a big decade
- [ ] Long period comets: out to the Oort Cloud and with orbits greater than 200 years, they have orbits of thousands of years. Hale-Bopp is 2500 years
- [ ] Short period comets: Kuiper belt and less than 200 year orbit. Halley’s comet is 76 years
- [ ] The sun, planets, and other gravities have an effect on the orbit of comets and change their orbit
- [ ] Comets are made from the remnants of planets and the beginning of our solar system
- [ ] Comets and ice
- [ ] The chemical make up of comets
- [ ] Chemistry
- [ ] Lots of technical stuff about comets; composition, tail, movement
- [ ] A section about the history of the swastika and how it could actually be a comet
- [ ] The Oort Cloud
- [ ] Comet: primarily composed of ice and dust, contain long/short orbits, have a tail/nucleolus, larger than a meteor, often many kilometers in size
- [ ] Asteroid: the remnants of planets, composed of mineral and rock, typically live in the astroid belt, are not seen by the naked eye, don’t have a tail/nucleolus
- [ ] Meteor: a small piece of a comet or asteroid that breaks off and burns up in the atmosphere
- [ ] The origins of our solar system
- [ ] Cataclysms, extinctions, comets
- [ ] Again he mentions human’s negative impact on the planet and us being the cause of animal extinction. Also we are the ones that can stop it.
- [ ] We intercepted and took photos of comets in his life time, he talks about it. In the past ten years we have landed on a comet, collected samples, and they are being returned to Earth. Science and math are amazing.
- [ ] I always think of his line about theologians not being able to predict god but scientists can predict the timing and place of comets and planets to such a precise point that we can land rovers on them.
- [ ] Even when I am zoned out during this book I have an image of a comet hurtling through the lonely darkness of space. Although the solar system does not seem as lonely. Sagan has made me feel like it is smaller and a family. The opening chapters of placing me on a comet for millions of years, that image and feeling has stayed with me throughout the book.
- [ ] He talks about mining comets, living on comets, and traveling on comets
- [ ] Halley’s comet has been noted by civilizations across the planet since at least 200 BCE. It is a time capsule of our world. It has been recorded on animals skins and in clay tablets. It visits us once a life time. It is poetic.
- [ ] Sagan ends in a typical Sagan way. Reminding us of the importance of our planet, the fragility of our existence, the importance and absolute insignificance of our life on this tiny rock. We are floating in a infinite ocean of the cosmos. Sagan always hits with magic, wonder, and aww.
- [ ] Comets are really the only travelers of the cosmic ocean.
- [ ] Not the most engaging of his books but beautiful and timeless
September 21, 2018
Mysterious Traveler:
Once upon a time, the young Albert Einstein tried to imagine what it would be like to ride on a beam of light and what the universe would look like to that observer. Writing in his 1985 book, Comet, author Carl Sagan takes the reader on another imaginary journey. This time the observer is riding aboard a wayward comet traveling from the Solar System's outer fringe, around the sun and back into deep space again, giving the reader a birds eye view of what you would see on such a trip. Who knows where such "flights of fancy" can lead? The former; to a paradigm changing theory. And the latter; to an in depth look at a strange visitor from the depths of space. Part science, part history and, in the original hard-bound edition, a generous helping of classical and new art work. While the Kindle edition has the charts, graphs and many black & white illustrations the beautiful color paintings are either missing or rendered in B&W. While this does not diminish Sagan's text in any way, it would have been a nice addition to the overall reading experience. You have to wonder what the publishers were thinking when they OK'd this treatment of both Cosmos and Comet for e-reader release. The text itself is stunning, Sagan's knowledge seems unlimited and his writing skills were never better. This edition is the 1997 update by co-author Ann Druyan to include any new findings (to that point) and theories on comets and astronomy but you may want to use this book as a jumping off point to more recent writings. The history of comets and how they interacted with human society is fascinating and Sagan takes you back to the beginning, to our earliest records of comet sightings. What are comets made of? How are they formed? Follow the birth and life of our Mysterious Traveler on it's journey through the Solar System. The author covers the mechanics of how their orbits are created and the risk that comets may pose to our planet. If a large object, comet or meteor, ever struck the Earth it could have a devastating effect on our environment and all life, including humans. Has this ever happened? What is the connection between comets and meteorites? Sagan covers all this and more in this classic science book. The book closes with a section of extreme speculation and philosophy that the author offers up for your consideration, take it for what you will, just keep an open mind. From Sagan's point of view the future has boundless possibilities. Comets may be an unlimited resource of water, minerals and energy that we can mine for use in space-construction or colonization of other planets. All it needs is the courage to take a course of action that will benefit us in the short run and future generations in the long run as well. Whether you're reading Comet for the science, history, or just for nostalgic reasons it's a worthwhile read. So buy your ticket and hop aboard the Comet express. There's always room for another observer. I had no technical or formatting problems with this Kindle edition.
Last Ranger
Once upon a time, the young Albert Einstein tried to imagine what it would be like to ride on a beam of light and what the universe would look like to that observer. Writing in his 1985 book, Comet, author Carl Sagan takes the reader on another imaginary journey. This time the observer is riding aboard a wayward comet traveling from the Solar System's outer fringe, around the sun and back into deep space again, giving the reader a birds eye view of what you would see on such a trip. Who knows where such "flights of fancy" can lead? The former; to a paradigm changing theory. And the latter; to an in depth look at a strange visitor from the depths of space. Part science, part history and, in the original hard-bound edition, a generous helping of classical and new art work. While the Kindle edition has the charts, graphs and many black & white illustrations the beautiful color paintings are either missing or rendered in B&W. While this does not diminish Sagan's text in any way, it would have been a nice addition to the overall reading experience. You have to wonder what the publishers were thinking when they OK'd this treatment of both Cosmos and Comet for e-reader release. The text itself is stunning, Sagan's knowledge seems unlimited and his writing skills were never better. This edition is the 1997 update by co-author Ann Druyan to include any new findings (to that point) and theories on comets and astronomy but you may want to use this book as a jumping off point to more recent writings. The history of comets and how they interacted with human society is fascinating and Sagan takes you back to the beginning, to our earliest records of comet sightings. What are comets made of? How are they formed? Follow the birth and life of our Mysterious Traveler on it's journey through the Solar System. The author covers the mechanics of how their orbits are created and the risk that comets may pose to our planet. If a large object, comet or meteor, ever struck the Earth it could have a devastating effect on our environment and all life, including humans. Has this ever happened? What is the connection between comets and meteorites? Sagan covers all this and more in this classic science book. The book closes with a section of extreme speculation and philosophy that the author offers up for your consideration, take it for what you will, just keep an open mind. From Sagan's point of view the future has boundless possibilities. Comets may be an unlimited resource of water, minerals and energy that we can mine for use in space-construction or colonization of other planets. All it needs is the courage to take a course of action that will benefit us in the short run and future generations in the long run as well. Whether you're reading Comet for the science, history, or just for nostalgic reasons it's a worthwhile read. So buy your ticket and hop aboard the Comet express. There's always room for another observer. I had no technical or formatting problems with this Kindle edition.
Last Ranger
April 30, 2023
The Good: Accessible science for the wonder and awe of our existence
The Bad: A little outdated
The Literary: Brings together history and biography to tell the story of our astrophysical visitors
Comets grace our skies, changing the heavens for a brief time, bringing uncertainty and doubt, death, and maybe life itself.
This book is structured in such a way that reading it is a journey of discovery. The introduction is from the point of view of a narrator astride a comet hurtling through the galaxy. From there, humanity's myths about comets progress through the ages, and it's wonderful to see emphasis placed on both eastern and southern (in addition to western) interpretations. The !Kung tribe of the Upper Omuramba in what is now Namibia were unique in their view of a comet as a guarantee of good times ahead. The Chinese are unparalleled in their systematic records since 1400 BC, only missing the return of Halley's comet once. Seneca debated against Aristotle's belief that comets were sub-lunar weather-phenomena, but that view held firm for two thousand years in the west.
When the age of the Renaissance and Enlightenment gave rise to the field of science in its infancy, the authors show each theory and discovery in turn. The tides turned with scientist Edmond Halley, who as a boy witnessed two comets—one in 1664, popularly associated with the Great Plague of London, the other in 1665, connected with the Great Fire. Halley's wonder for science and experimentation flourishes, and as a plucky eighteen-year-old, he wrote to John Flamsteed, England’s first Astronomer Royal, informing him that the authoritatively published tables on the positions of Jupiter and Saturn were in error.
Halley seems to have been an all around cool guy, getting along with all the big egos of the day, remaining unbiased, and often chosen by the Royal Society to perform repeat measurements of controversial findings. Halley convinced recluse Isaac Newton to publish his incredible theories about gravity. Halley accepted a demotion to become the Royal Society's secretary, a lowly job without the honor of wearing a wig, because no one else was willing to do it. Among his many interests, he invented, developed, and tested one of the first practical diving bells. He wanted to study the work of the ancient mathematician Apollonius, but due to the burning of the Library of Alexandria, no copies in Greek survived, so, at the age forty-nine, Halley taught himself Arabic. But most famously, Halley catalogued, studied, and concluded that the slight differences in the orbital elements of the comets of 1531, 1607, and 1682 were in fact visitations of the same comet. He may have been the first ever scientist to prophesize an event 50 years in the future, and be right!
Immanuel Kant, writer and philosopher, also studied the skies and was the first to postulate that the Milky Way was only one of innumerable other galaxies, a perspective not fully demonstrated until the 1920s. Because of his many radical views, Kant dedicated his book to Prussian emperor Frederick the Great, so he'd be likely to stay in good graces with the government. Later in life Kant strongly supported the American and French antiroyalist revolutions, and Frederick's successor gave Kant a cabinet order deploring his “misuse” of philosophy. One of the things I love about this book the ability to bring in just enough historical context to enrich the scientific story.
In the early 20th century, astronomer Camille Flammarion predicted of Halley's comet that “the cyanogen gas would impregnate the atmosphere [of the Earth] and possibly snuff out all life on the planet.” Together with the fears of chemical warfare of the time, and a pervading dread of comets throughout human history, a global pandemonium ensued that was completely unnecessary.
But back to comets; I love learning about their life cycle. Even as we have perceived them primarily as portents of doom, they are themselves extinguishing their own matter each time they pass the sun. Composed primarily of different types of ice and dust all mixed up, the sun vaporizes the ice in spurts, creating the tails. Water ice has a specific rigid structure, in which foreign molecules are physically trapped in a molecular cage. A typical cometary nucleus contains about as much snow as falls each year the Northern United States. Most comets rotate and have days similar to those of Earth. Comets "die" in one of several ways—disintegration, hitting the sun, moons, or planets, or injection into the solar system.
Now, we probe comets with different types of light through spectroscopy. Some comets are composed of mostly silicates like rocks. Those that traverse close to the sun feature metals like chromium, nickel, and copper. We classify two types of comet tails. Type I emanate a blue light because of the fluorescence of CO+. Type II appear yellow because they reflect sunlight back to us. A comet tail always points away from the sun, blown back by solar wind radiation, whether the comet is making its way toward the sun or away from it.
Dense cratering of moons and other planets that have no active geological activity supports the theory that space boulders and icebergs were once extremely numerous, and indeed planets originally formed by all sorts of crashing into things. Now most of the comets reside in the Oort cloud just outside of our solar system. The number of comets in the Oort Cloud is thus larger than the number of stars in the Milky Way Galaxy, so you'd think they'd still be crashing into each other all the time, but the Oort Cloud is so big, current evidence suggests that the distance between comets is about the distance from Earth to Uranus.
Back here on Earth, a foray into geology provides the evidence for the theory of a comet impact as the inciting incident for the Cretaceous extinctions. In between two limestone layers, a clay layer is infused with iridium, a common comet ingredient. From the thickness of the clay layer, it follows that the iridium was not deposited instantaneously, but over 10,000 or even 100,000 years. Multiple comets are likely to have been involved, and particles ejected into the atmosphere by impact would have settled very slowly. The atmospheric particles blocked out the sun, dropping the average temperature on Earth from warmer than it is now to below freezing.
Later chapters of the book tend toward theory and speculation. Some scientists argue there is evidence that supports a mass extinction or a comet crater every 30 million years. In addition, the sun has its own periodicity, bobbing up and down through the galactic plane about every 30 million years. I will have to follow up on the current research. Could comets be the cause of our recurring extinctions? Could they also have deposited the necessary ingredients for life on Earth? Could we one day colonize and pilot them as interplanetary spaceships? What will humanity accomplish before the next visit of Halley's comet in 2061?
Highly recommended for everyone! Hail Sagan!
The Bad: A little outdated
The Literary: Brings together history and biography to tell the story of our astrophysical visitors
Comets grace our skies, changing the heavens for a brief time, bringing uncertainty and doubt, death, and maybe life itself.
This book is structured in such a way that reading it is a journey of discovery. The introduction is from the point of view of a narrator astride a comet hurtling through the galaxy. From there, humanity's myths about comets progress through the ages, and it's wonderful to see emphasis placed on both eastern and southern (in addition to western) interpretations. The !Kung tribe of the Upper Omuramba in what is now Namibia were unique in their view of a comet as a guarantee of good times ahead. The Chinese are unparalleled in their systematic records since 1400 BC, only missing the return of Halley's comet once. Seneca debated against Aristotle's belief that comets were sub-lunar weather-phenomena, but that view held firm for two thousand years in the west.
When the age of the Renaissance and Enlightenment gave rise to the field of science in its infancy, the authors show each theory and discovery in turn. The tides turned with scientist Edmond Halley, who as a boy witnessed two comets—one in 1664, popularly associated with the Great Plague of London, the other in 1665, connected with the Great Fire. Halley's wonder for science and experimentation flourishes, and as a plucky eighteen-year-old, he wrote to John Flamsteed, England’s first Astronomer Royal, informing him that the authoritatively published tables on the positions of Jupiter and Saturn were in error.
Halley seems to have been an all around cool guy, getting along with all the big egos of the day, remaining unbiased, and often chosen by the Royal Society to perform repeat measurements of controversial findings. Halley convinced recluse Isaac Newton to publish his incredible theories about gravity. Halley accepted a demotion to become the Royal Society's secretary, a lowly job without the honor of wearing a wig, because no one else was willing to do it. Among his many interests, he invented, developed, and tested one of the first practical diving bells. He wanted to study the work of the ancient mathematician Apollonius, but due to the burning of the Library of Alexandria, no copies in Greek survived, so, at the age forty-nine, Halley taught himself Arabic. But most famously, Halley catalogued, studied, and concluded that the slight differences in the orbital elements of the comets of 1531, 1607, and 1682 were in fact visitations of the same comet. He may have been the first ever scientist to prophesize an event 50 years in the future, and be right!
Immanuel Kant, writer and philosopher, also studied the skies and was the first to postulate that the Milky Way was only one of innumerable other galaxies, a perspective not fully demonstrated until the 1920s. Because of his many radical views, Kant dedicated his book to Prussian emperor Frederick the Great, so he'd be likely to stay in good graces with the government. Later in life Kant strongly supported the American and French antiroyalist revolutions, and Frederick's successor gave Kant a cabinet order deploring his “misuse” of philosophy. One of the things I love about this book the ability to bring in just enough historical context to enrich the scientific story.
In the early 20th century, astronomer Camille Flammarion predicted of Halley's comet that “the cyanogen gas would impregnate the atmosphere [of the Earth] and possibly snuff out all life on the planet.” Together with the fears of chemical warfare of the time, and a pervading dread of comets throughout human history, a global pandemonium ensued that was completely unnecessary.
But back to comets; I love learning about their life cycle. Even as we have perceived them primarily as portents of doom, they are themselves extinguishing their own matter each time they pass the sun. Composed primarily of different types of ice and dust all mixed up, the sun vaporizes the ice in spurts, creating the tails. Water ice has a specific rigid structure, in which foreign molecules are physically trapped in a molecular cage. A typical cometary nucleus contains about as much snow as falls each year the Northern United States. Most comets rotate and have days similar to those of Earth. Comets "die" in one of several ways—disintegration, hitting the sun, moons, or planets, or injection into the solar system.
Now, we probe comets with different types of light through spectroscopy. Some comets are composed of mostly silicates like rocks. Those that traverse close to the sun feature metals like chromium, nickel, and copper. We classify two types of comet tails. Type I emanate a blue light because of the fluorescence of CO+. Type II appear yellow because they reflect sunlight back to us. A comet tail always points away from the sun, blown back by solar wind radiation, whether the comet is making its way toward the sun or away from it.
Dense cratering of moons and other planets that have no active geological activity supports the theory that space boulders and icebergs were once extremely numerous, and indeed planets originally formed by all sorts of crashing into things. Now most of the comets reside in the Oort cloud just outside of our solar system. The number of comets in the Oort Cloud is thus larger than the number of stars in the Milky Way Galaxy, so you'd think they'd still be crashing into each other all the time, but the Oort Cloud is so big, current evidence suggests that the distance between comets is about the distance from Earth to Uranus.
Back here on Earth, a foray into geology provides the evidence for the theory of a comet impact as the inciting incident for the Cretaceous extinctions. In between two limestone layers, a clay layer is infused with iridium, a common comet ingredient. From the thickness of the clay layer, it follows that the iridium was not deposited instantaneously, but over 10,000 or even 100,000 years. Multiple comets are likely to have been involved, and particles ejected into the atmosphere by impact would have settled very slowly. The atmospheric particles blocked out the sun, dropping the average temperature on Earth from warmer than it is now to below freezing.
Later chapters of the book tend toward theory and speculation. Some scientists argue there is evidence that supports a mass extinction or a comet crater every 30 million years. In addition, the sun has its own periodicity, bobbing up and down through the galactic plane about every 30 million years. I will have to follow up on the current research. Could comets be the cause of our recurring extinctions? Could they also have deposited the necessary ingredients for life on Earth? Could we one day colonize and pilot them as interplanetary spaceships? What will humanity accomplish before the next visit of Halley's comet in 2061?
Highly recommended for everyone! Hail Sagan!
July 25, 2011
Rating: 6.5/10. The volume I read was not the revised version but the original which was released in 1985 just BEFORE Halley's Comet. Sagan obviously was trying to cash in on the interest in the comet. The problem with reading science books which are more than 20 years old is that much of the material is dated, incorrect, speculation, or irrelevant. So while Sagan offers much which is interesting there is none of the later research such as the 'Giotto' mission or the comet Shumaker-Levy which crashed into Jupiter. I'm not sure whether some of his theories were either proved or not proved....for example, the notion that extinctions occur on Earth roughly every 30 million years is caused by the 'bobbing' of the sun through the plane of the galaxy as it revolves around its centre. I did enjoy the book, and, yes, it does have lots of pictures and photos. However, as always happens when I read books like this I realize it is time to find a modern, up-to-date, latest theories text.
October 29, 2008
This is my least favorite of 6 books I've read of the late Carl Sagan and I love his work. I learned very interesting things about comets, but it seemed like I could have learned them all in about one-fifth of this book. He was capable of much more concise writing, and this book suffers from being obsolete as we continue to learn more about the celestial bodies with ongoing robotic probes.
August 4, 2020
It feels like a publisher threw cash at Carl to quickly throw a book on comets together ahead of Halley's comet's arrival in '86, and then marketed it as though it were is substance the successor to the revered Cosmos.
September 25, 2025
El Cometa es un libro totalmente necesario para quienes tenemos curiosidad por el Universo y sus orígenes, tales como Historia del Tiempo de Hawking, Cosmos del mismo Carl Sagan, entre otros que nos han enamorado con su maestría en divulgación. El Cometa examina 1) socialmente, 2) cronológicamente, 3) químicamente, 4) antropológicamente y 5) astrofísicamente la presencia de los cometas en el Universo, y su relación con el ser humano. La palabra antropología es clave, ya que Carl Sagan examina (como siempre lo hace) con detalles cómo la observación de estos "entes sobrenaturales" han impactado a la humanidad desde sus propios orígenes; como diversas culturas le han dado un significado a los cometas, en la China ancestral eran en su mayoría malos presagios, pero para algunos pueblos, la presencia de los cometas era un buen augurio.
Desconocía totalmente que la esvástica utilizada en el ejército nazi, es un símbolo que se ha encontrado en una gran cantidad de vestigios arqueológicos, desde tribus en África, Australia, China, en romanos, griegos e incluso etruscos, y no olvidar en antiguos pueblos del Extremo Oriente.
La composición química, tal y como es la presencia de clatratos que encierran materiales exóticos, va de la mano con la explicación de que la vida en la Tierra apareció mil millones de años después de la creación del Sistema Solar. Las sustancias que componen la materia orgánica, la misma que logró unificarse en ARN y posteriormente con mayor complejidad en ADN, están en su mayoría fuera de la tierra, por tanto, en un paralelismo con John Gribbin, es evidencia que los cometas, durante el gran bombardeo tardío, hayan aportado con moléculas que sean amigables para la vida.
¿Cómo no enamorarse de un libro así?
¿Cómo no prosternarse ante la cosmología y sus ciencias relativas?
Es una maravilla de libro, ya que incluso explora la vida de grandes contribuyentes al conocimiento de la astrofísica y de la astronomía, al igual que la percepción trágica característica de la Edad Oscura.
Carl Sagan siempre deslumbra, y este libro no es una excepción para quienes creemos saber tan solo un poquito de la mecánica del Universo.
Desconocía totalmente que la esvástica utilizada en el ejército nazi, es un símbolo que se ha encontrado en una gran cantidad de vestigios arqueológicos, desde tribus en África, Australia, China, en romanos, griegos e incluso etruscos, y no olvidar en antiguos pueblos del Extremo Oriente.
La composición química, tal y como es la presencia de clatratos que encierran materiales exóticos, va de la mano con la explicación de que la vida en la Tierra apareció mil millones de años después de la creación del Sistema Solar. Las sustancias que componen la materia orgánica, la misma que logró unificarse en ARN y posteriormente con mayor complejidad en ADN, están en su mayoría fuera de la tierra, por tanto, en un paralelismo con John Gribbin, es evidencia que los cometas, durante el gran bombardeo tardío, hayan aportado con moléculas que sean amigables para la vida.
¿Cómo no enamorarse de un libro así?
¿Cómo no prosternarse ante la cosmología y sus ciencias relativas?
Es una maravilla de libro, ya que incluso explora la vida de grandes contribuyentes al conocimiento de la astrofísica y de la astronomía, al igual que la percepción trágica característica de la Edad Oscura.
Carl Sagan siempre deslumbra, y este libro no es una excepción para quienes creemos saber tan solo un poquito de la mecánica del Universo.
October 19, 2022
Of the great pairings of human beings through the ages, Carl Sagan and Ann Druyan should be counted. Their writing and public persuasion of scientific arguments have had a tremendous effect on my generation to pursue science.
This book is both a history and compendium of comets in anticipation of the modern arrival of Halley's comet. The corners of each page have a flip-through of that comet's traverse along its 76-year elliptical orbit.
It has been only 112 years since comet Halley terrified millions of people everywhere about its potential to wipe out earthly society, either by passage through its tail containing cyanide, or by burning the population alive. Thankfully, it did neither, nor was its cometary nucleus on a tragic trajectory to strike the Earth, so that by its return in 1985, comet Halley and comets, in general, became less harbingers of destruction and more objects worthy of intense scientific study and observation.
Because some comets, asteroids, and other so-called Near-Earth Objects (NEOs) do pose a danger of collision with our planet, the consequences range from insignificant to extinction level, and so our understanding of them needs to improve. Astronomers are busy finding, cataloging, and continually tracking objects that could cross Earth's path around the sun in the future. In fact, it's the mathematically predictable nature of comets propounded by Halley that makes their futures less uncertain.
But not all are known, and not all that can do extreme damage can be found. But for those we know, as NASA's recent DART mission showed, an object can be redirected in time to stave off a direct hit, given early enough warning.
It should be noted that Jupiter is routinely bombarded by sizable rocks and ice balls, and these have been directly observed by, and corroborated among, astronomers. Some impacts, such as comet Shoemaker-Levy 9, were witnessed unfolding in real-time in 1994 as the comet broke up into a 'string of pearls' 21 objects long, each of which entered Jupiter's atmosphere with enough energy to punch Earth-sized holes in the clouds. If it were not for the gas giant planets of Jupiter, Saturn, Uranus and Neptune, our world would not be spared major cometary impacts to this day. Feel lucky, or blessed.
My side interest in this book is one that overlaps with numismatics, the study of coins. Sagan and Druyan offer several pictorials of comets as devices on coins. Coinage from ancient Thrace (Greece, Turkey, Ionia, etc.) show symbols reminiscent of the swastika that may indicate a rotating comet spewing four tails, visible in daylight. Studying these coins confirms that the symbol may be attributed to a celestial object. If so, this is secondary evidence in recorded history of such objects visible to observers without modern telescopic instruments.
This is an interesting book for those interested in history, science, the universe, and space travel.
This book is both a history and compendium of comets in anticipation of the modern arrival of Halley's comet. The corners of each page have a flip-through of that comet's traverse along its 76-year elliptical orbit.
It has been only 112 years since comet Halley terrified millions of people everywhere about its potential to wipe out earthly society, either by passage through its tail containing cyanide, or by burning the population alive. Thankfully, it did neither, nor was its cometary nucleus on a tragic trajectory to strike the Earth, so that by its return in 1985, comet Halley and comets, in general, became less harbingers of destruction and more objects worthy of intense scientific study and observation.
Because some comets, asteroids, and other so-called Near-Earth Objects (NEOs) do pose a danger of collision with our planet, the consequences range from insignificant to extinction level, and so our understanding of them needs to improve. Astronomers are busy finding, cataloging, and continually tracking objects that could cross Earth's path around the sun in the future. In fact, it's the mathematically predictable nature of comets propounded by Halley that makes their futures less uncertain.
But not all are known, and not all that can do extreme damage can be found. But for those we know, as NASA's recent DART mission showed, an object can be redirected in time to stave off a direct hit, given early enough warning.
It should be noted that Jupiter is routinely bombarded by sizable rocks and ice balls, and these have been directly observed by, and corroborated among, astronomers. Some impacts, such as comet Shoemaker-Levy 9, were witnessed unfolding in real-time in 1994 as the comet broke up into a 'string of pearls' 21 objects long, each of which entered Jupiter's atmosphere with enough energy to punch Earth-sized holes in the clouds. If it were not for the gas giant planets of Jupiter, Saturn, Uranus and Neptune, our world would not be spared major cometary impacts to this day. Feel lucky, or blessed.
My side interest in this book is one that overlaps with numismatics, the study of coins. Sagan and Druyan offer several pictorials of comets as devices on coins. Coinage from ancient Thrace (Greece, Turkey, Ionia, etc.) show symbols reminiscent of the swastika that may indicate a rotating comet spewing four tails, visible in daylight. Studying these coins confirms that the symbol may be attributed to a celestial object. If so, this is secondary evidence in recorded history of such objects visible to observers without modern telescopic instruments.
This is an interesting book for those interested in history, science, the universe, and space travel.
July 25, 2020
Comet is a masterpiece of scientific writing. Carl Sagan and Ann Druyan wrote this book for the return of Halley's Comet in 1985. It goes over the history and cultural implications of comets in our society.
Sagan opens the book with a thought experiment. Imagine that you are flying through space astride a comet. You start at the Oort Cloud. A force tugs at the comet, spoiling the delicate balance of forces suspending it in that location. A comet is a small, icy body that travels through the solar system. As the comet approaches the sun, it grows a tail due to the solar radiation that batters it.
Sagan takes several chapters to explain what comets mean to different civilizations. Nicolaus Copernicus, Johannes Kepler, Isaac Newton, Tycho Brahe, and Edmund Halley all participated in modernizing astronomy. Aristotle was taken seriously for centuries. Eventually, it became too much to maintain. With the advent of the telescope, human beings could finally see beyond the reach of the naked eye.
Sagan explores the Alvarez Hypothesis. At the time, it was a new idea.
Comet is a beautifully illustrated book. Sagan writes clearly. In short, I have no complaints. The only issue I can think of is that the book was written in 1985 and is dated. This is hardly Sagan's fault, though. He did an excellent job considering the technology of the time.
Sagan opens the book with a thought experiment. Imagine that you are flying through space astride a comet. You start at the Oort Cloud. A force tugs at the comet, spoiling the delicate balance of forces suspending it in that location. A comet is a small, icy body that travels through the solar system. As the comet approaches the sun, it grows a tail due to the solar radiation that batters it.
Sagan takes several chapters to explain what comets mean to different civilizations. Nicolaus Copernicus, Johannes Kepler, Isaac Newton, Tycho Brahe, and Edmund Halley all participated in modernizing astronomy. Aristotle was taken seriously for centuries. Eventually, it became too much to maintain. With the advent of the telescope, human beings could finally see beyond the reach of the naked eye.
Sagan explores the Alvarez Hypothesis. At the time, it was a new idea.
Comet is a beautifully illustrated book. Sagan writes clearly. In short, I have no complaints. The only issue I can think of is that the book was written in 1985 and is dated. This is hardly Sagan's fault, though. He did an excellent job considering the technology of the time.
April 24, 2020
Following on the heels of Carl Sagan’s success with Cosmos (which this book strongly resembles, at least visually), he teams up with Ann Druyan to focus more narrowly on a topic that was hot when this book came out in 1985 (thanks to the perihelion passage of Halley’s Comet). Though not really on par with Sagan’s more famous work, this nonetheless makes for an interesting read. I didn’t know much about comets prior to picking this up, and now I’d like to learn more about what we’ve learned about them in the two decades since this book came out. In spots the text drifts off into wild speculation, an unwelcome element that’s joined at the end by a loss of organization and the usual indulgence of Sagan’s now-quaint obsession with nuclear war. Overall, however, this is a worthwhile read for anyone in my shoes: possessed of an interest in the subject but not much knowledge about it.
June 2, 2022
I previously did not think much of comets but that all changed when i read this book. I now realize that they are one of the most spectacular celestial objects in our night sky. This book covers everything about comets; their origins, what they are made of, how ancient civilizations saw them, the myths, fears, and stories they told. It goes all the way through history and different cultures to the modern scientific understanding of comets. It also the covers the stories of notable figures and scientists who made valuable contributions to the study of comets such as Isaac Newton and Edmond Halley. The last part of the book reflects on the evolution of our species and shows what role the comets have played for us to get here and what the future implications might be. Overall, the book is a must-read for anyone who wants to know more about these majestic celestial bodies called comets.
January 19, 2024
Well illustrated and lovingly written, I tried three times to read this book and just couldn't manage it.
I read Contact and really enjoyed it, especially after seeing the movie.
This book explores the life of comets and their impact (sorry for the pun) on the solar system. It is beautifully illustrated on heavy paper - so I did just that, looked at the illustrations and skimmed and sifted through the material I wanted to glean for more knowledge.
I received an Astronomy course from the Teaching Company for the holidays and shall take a closer look at comets then.
I read Contact and really enjoyed it, especially after seeing the movie.
This book explores the life of comets and their impact (sorry for the pun) on the solar system. It is beautifully illustrated on heavy paper - so I did just that, looked at the illustrations and skimmed and sifted through the material I wanted to glean for more knowledge.
I received an Astronomy course from the Teaching Company for the holidays and shall take a closer look at comets then.
August 14, 2024
Perfect informative source on comets. Their origin, composition, life paths and end. Humanities perceptions of them from early man up to now.
My only reason for a lower rating is purely based on my own enjoyment and boredom. As someone who loves sci fi, my own understanding of the sciences is pretty average. I often read science nonfiction with the hopes of personal growth through learning but often find it hard to focus, keep up and really learn. By the end of this, finishing it was more of a chore than anything else.
My only reason for a lower rating is purely based on my own enjoyment and boredom. As someone who loves sci fi, my own understanding of the sciences is pretty average. I often read science nonfiction with the hopes of personal growth through learning but often find it hard to focus, keep up and really learn. By the end of this, finishing it was more of a chore than anything else.
July 2, 2019
Journey through space with a comet, then explore the myths that arose around these celestial travelers. In this informative book, readers can investigate the scientific findings surrounding comets while learning how they spurred some great scientific discoveries.
Filled with amazing photographs, sketches, and diagrams, this is a definitive scientific work on comets. Readers with an interest in space science and the universe will find much to appreciate here.
Highly recommended.
Filled with amazing photographs, sketches, and diagrams, this is a definitive scientific work on comets. Readers with an interest in space science and the universe will find much to appreciate here.
Highly recommended.
September 5, 2020
What's it like to ride around the sun on a comet? In this book Carl Sagan perfectly describes the journey along with a history of comets and how different cultures have viewed them. You will learn what comets are made of and how they travel through the solar system. Whenever I read a book like this it amazes how much humans have discovered about the universe... and how much there is still to discover.
July 14, 2020
Love this book - now need to read more on Edmond Halley.
Love the way that Sagan's books empbody the joy of space, Astronomy and science and instils within it a love of history of science and awe at the geniuses of earlier times fundemental in building our modern view of science and the universe. The science is written in a way to impart concepts without overwhelming mathematic proofs.
Love the way that Sagan's books empbody the joy of space, Astronomy and science and instils within it a love of history of science and awe at the geniuses of earlier times fundemental in building our modern view of science and the universe. The science is written in a way to impart concepts without overwhelming mathematic proofs.
December 22, 2020
Sagan's soft-corner for comets is well known, and in this book he does sell out a bit. But even then, it's another superb read, with flashes of brilliant prose, and nuggets of wisdom strewn all over. The science has most likely moved on in the 25+ years since the book was published, but you can still learn a lot if you are not steeped in cometary science already.
April 27, 2024
40% of the book is about superstitious things different cultures believed throughout history
20% - quotes which mentioned comets from different authors
20% - word soup
10% - speculation about the future where humanity will mine asteroids and live on comets
10% - actual but dated info about comets
20% - quotes which mentioned comets from different authors
20% - word soup
10% - speculation about the future where humanity will mine asteroids and live on comets
10% - actual but dated info about comets
February 20, 2019
This was interesting but not the most engrossing book I've ever read. I still enjoyed learning about the origin and composition of comets and their role in the solar system, but I felt like a lot of information was a little bit redundant and at times I definitely felt my attention begin to wander.
July 9, 2019
Carl Sagan's writing is always enjoyable, but this book focused on a narrower topic than his others have and it gets a bit bogged down in details. As a result, it lacks the larger sense of wonder that his other books convey.
April 5, 2021
3/5
I loved Pale Blu Dot, and I love Sagan's original Cosmos series (Sorry NDT, even though some of the science is outdated, it has more heart!), but this one, while informative, was kind of boring and It is my least favorite Carl Sagan book I've read so far.
I loved Pale Blu Dot, and I love Sagan's original Cosmos series (Sorry NDT, even though some of the science is outdated, it has more heart!), but this one, while informative, was kind of boring and It is my least favorite Carl Sagan book I've read so far.
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