Pale Blue Dot (book)
Encyclopedia
Pale Blue Dot: A Vision of the Human Future in Space (1994) is a non-fiction book by Carl Sagan
. It is the sequel to Cosmos: A Personal Voyage
and was inspired by the "Pale Blue Dot
" photograph, for which Sagan provides a sobering description. In this book, Sagan mixes philosophy about the human place in the universe with a description of the current knowledge about the Solar System
. He also details a human vision for the future.
species are unique. Sagan makes two claims for the persistence of the idea of a geocentric, or Earth-centered universe: human pride in our existence, and the threat of torturing those who dissented from it, particularly during the time of the Roman Inquisition
. However, he also admits that the scientific tools to prove the Earth
orbited the Sun
were (until the last few hundred years) not accurate enough to measure effects such as parallax
, making it difficult for astronomers to prove that the geocentric theory was false.
After saying that we have gained humility from understanding that we are not, literally, the center of the universe, Sagan embarks on an exploration of the entire solar system
. He begins with an account of the Voyager program
, in which Sagan was a participating scientist. He describes the difficulty of working with the low light levels at distant planets, and the mechanical and computer problems which beset the twin spacecraft as they aged, and which could not always be diagnosed and fixed remotely. Sagan then examines each one of the major planets, as well as some of the moons—including Titan
, Triton
, and Miranda
—focusing on whether life is possible at the frontiers of the solar system.
Sagan argues that studying other planet
s provides context for understanding the Earth—and protecting humanity's only home planet from environmental catastrophe. He believes that NASA
's decision to cut back exploration of the Moon
after the Apollo program was a short-sighted decision, despite the expense and the failing popularity of the program among the United States
public. Sagan says future exploration of space should focus on ways to protect Earth and to extend human habitation beyond it. The book was published the year after the comet Shoemaker-Levy 9
crashed into Jupiter
, an event Sagan uses to highlight the danger Earth faces from the occasional asteroid
or comet
large enough to cause substantial damage if it were to hit Earth. He says we need the political will to track large extraterrestrial objects, or we risk losing everything. Sagan argues that in order to save the human race, space colonization
and terraforming
should be utilized.
Later in the book, Sagan's wife, Ann Druyan
, challenges readers to pick one of the other planetary dots photographed and featured in the book, and imagine that there are inhabitants on that world who believe that the universe was created solely for themselves. She shared Sagan's belief that humans are not as important as they think they are.
The first edition of the book includes an extensive list of illustrations and photographs, mostly provided by NASA
. Other editions reference various figures, but which are not included.
Carl Sagan
Carl Edward Sagan was an American astronomer, astrophysicist, cosmologist, author, science popularizer and science communicator in astronomy and natural sciences. He published more than 600 scientific papers and articles and was author, co-author or editor of more than 20 books...
. It is the sequel to Cosmos: A Personal Voyage
Cosmos (book)
Cosmos is a popular science book by astronomer and Pulitzer Prize-winning author Carl Sagan. Its 13 illustrated chapters, corresponding to the 13 episodes of the Cosmos TV series on which the book was based, explore the mutual development of science and civilization...
and was inspired by the "Pale Blue Dot
Pale Blue Dot
The Pale Blue Dot is a photograph of planet Earth taken in 1990 by the Voyager 1 spacecraft from a record distance of about kilometers from Earth, as part of the solar system Family Portrait series of images. In the photograph, Earth is shown as a tiny dot against the vastness of space...
" photograph, for which Sagan provides a sobering description. In this book, Sagan mixes philosophy about the human place in the universe with a description of the current knowledge about the Solar System
Solar System
The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...
. He also details a human vision for the future.
Book summary
The first part of the book looks at the claims made throughout history that Earth and the humanHuman
Humans are the only living species in the Homo genus...
species are unique. Sagan makes two claims for the persistence of the idea of a geocentric, or Earth-centered universe: human pride in our existence, and the threat of torturing those who dissented from it, particularly during the time of the Roman Inquisition
Roman Inquisition
The Roman Inquisition was a system of tribunals developed by the Holy See during the second half of the 16th century, responsible for prosecuting individuals accused of a wide array of crimes related to heresy, including Protestantism, sorcery, immorality, blasphemy, Judaizing and witchcraft, as...
. However, he also admits that the scientific tools to prove the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
orbited the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
were (until the last few hundred years) not accurate enough to measure effects such as parallax
Parallax
Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines. The term is derived from the Greek παράλλαξις , meaning "alteration"...
, making it difficult for astronomers to prove that the geocentric theory was false.
After saying that we have gained humility from understanding that we are not, literally, the center of the universe, Sagan embarks on an exploration of the entire solar system
Solar System
The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...
. He begins with an account of the Voyager program
Voyager program
The Voyager program is a U.S program that launched two unmanned space missions, scientific probes Voyager 1 and Voyager 2. They were launched in 1977 to take advantage of a favorable planetary alignment of the late 1970s...
, in which Sagan was a participating scientist. He describes the difficulty of working with the low light levels at distant planets, and the mechanical and computer problems which beset the twin spacecraft as they aged, and which could not always be diagnosed and fixed remotely. Sagan then examines each one of the major planets, as well as some of the moons—including Titan
Titan (moon)
Titan , or Saturn VI, is the largest moon of Saturn, the only natural satellite known to have a dense atmosphere, and the only object other than Earth for which clear evidence of stable bodies of surface liquid has been found....
, Triton
Triton (moon)
Triton is the largest moon of the planet Neptune, discovered on October 10, 1846, by English astronomer William Lassell. It is the only large moon in the Solar System with a retrograde orbit, which is an orbit in the opposite direction to its planet's rotation. At 2,700 km in diameter, it is...
, and Miranda
Miranda (moon)
-External links:* at * at The Nine8 Planets* at Views of the Solar System* * from the...
—focusing on whether life is possible at the frontiers of the solar system.
Sagan argues that studying other planet
Planet
A planet is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, science,...
s provides context for understanding the Earth—and protecting humanity's only home planet from environmental catastrophe. He believes that NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
's decision to cut back exploration of the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
after the Apollo program was a short-sighted decision, despite the expense and the failing popularity of the program among the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
public. Sagan says future exploration of space should focus on ways to protect Earth and to extend human habitation beyond it. The book was published the year after the comet Shoemaker-Levy 9
Comet Shoemaker-Levy 9
Comet Shoemaker–Levy 9 was a comet that broke apart and collided with Jupiter in July 1994, providing the first direct observation of an extraterrestrial collision of solar system objects. This generated a large amount of coverage in the popular media, and the comet was closely observed by...
crashed into Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
, an event Sagan uses to highlight the danger Earth faces from the occasional asteroid
Asteroid
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
or comet
Comet
A comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...
large enough to cause substantial damage if it were to hit Earth. He says we need the political will to track large extraterrestrial objects, or we risk losing everything. Sagan argues that in order to save the human race, space colonization
Space colonization
Space colonization is the concept of permanent human habitation outside of Earth. Although hypothetical at the present time, there are many proposals and speculations about the first space colony...
and terraforming
Terraforming
Terraforming of a planet, moon, or other body is the hypothetical process of deliberately modifying its atmosphere, temperature, surface topography or ecology to be similar to those of Earth, in order to make it habitable by terrestrial organisms.The term is sometimes used more generally as a...
should be utilized.
Later in the book, Sagan's wife, Ann Druyan
Ann Druyan
Ann Druyan is an American author and producer specializing in productions about cosmology and popular science. She made substantial contributions to the PBS documentary series, Cosmos, and was the wife of late scientist and educator, Carl Sagan.-Film career:Along with Carl Sagan and Steven Soter,...
, challenges readers to pick one of the other planetary dots photographed and featured in the book, and imagine that there are inhabitants on that world who believe that the universe was created solely for themselves. She shared Sagan's belief that humans are not as important as they think they are.
The first edition of the book includes an extensive list of illustrations and photographs, mostly provided by NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
. Other editions reference various figures, but which are not included.
Chapters
- Wanderers: An Introduction
- You Are Here
- Aberrations of Light
- The Great Demotions
- A Universe Not Made for Us
- Is There Intelligent Life on Earth?
- The Triumph of Voyager
- Among the Moons of Saturn
- The First New Planet
- An American Ship at the Frontiers of the Solar System
- Sacred Black
- Evening and Morning Star
- The Ground Melts
- The Gift of Apollo
- Exploring Other Worlds and Protecting This One
- The Gates of the Wonder World Open
- Scaling Heaven
- Routine Interplanetary Violence
- The Marsh of Camarina
- Remaking the Planets
- Darkness
- To the Sky!
- Tiptoeing Through the Milky Way
See also
- Carl SaganCarl SaganCarl Edward Sagan was an American astronomer, astrophysicist, cosmologist, author, science popularizer and science communicator in astronomy and natural sciences. He published more than 600 scientific papers and articles and was author, co-author or editor of more than 20 books...
- Pale Blue DotPale Blue DotThe Pale Blue Dot is a photograph of planet Earth taken in 1990 by the Voyager 1 spacecraft from a record distance of about kilometers from Earth, as part of the solar system Family Portrait series of images. In the photograph, Earth is shown as a tiny dot against the vastness of space...
- Cosmos: A Personal VoyageCosmos: A Personal VoyageCosmos: A Personal Voyage is a thirteen-part television series written by Carl Sagan, Ann Druyan, and Steven Soter, with Sagan as presenter. It was executive-produced by Adrian Malone, produced by David Kennard, Geoffrey Haines-Stiles and Gregory Andorfer, and directed by the producers, David...
- Cosmos (book)Cosmos (book)Cosmos is a popular science book by astronomer and Pulitzer Prize-winning author Carl Sagan. Its 13 illustrated chapters, corresponding to the 13 episodes of the Cosmos TV series on which the book was based, explore the mutual development of science and civilization...
- The Blue MarbleThe Blue MarbleThe Blue Marble is a famous photograph of the Earth taken on December 7, 1972, by the crew of the Apollo 17 spacecraft at a distance of about ....
External links
- Sagan's rationale for human spaceflight Article about Carl Sagan and Pale Blue Dot
- Spaceflight or Extinction: Carl Sagan Excerpts from Pale Blue Dot
- A new picture of Earth taken through the rings of Saturn by the Cassini spacecraft on September 15, 2006. More information about photo.
- We Are Here: The Pale Blue Dot. A short fan-made film on The Pale Blue Dot, released a decade after Dr. Sagan's death. The posthumous narration is from Sagan himself, taken from one version of the audiobook version of "Pale Blue Dot".
- Unofficial film version of Chapter One (Google Video)
- A partial video tour of the Sagan Planet Walk monument in Ithaca, NY
- Carl Sagan reads from Pale Blue Dot about Galileo