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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Carl Sagan | 7/13 | https://en.wikipedia.org/wiki/Carl_Sagan | reference | science, encyclopedia | 2026-05-05T13:17:36.414677+00:00 | kb-cron |
One of his most famous quotations, "extraordinary claims require extraordinary evidence", is called the "Sagan standard" by some. It was based on a nearly identical statement by fellow founder of the Committee for the Scientific Investigation of Claims of the Paranormal, Marcello Truzzi, "An extraordinary claim requires extraordinary proof." This idea had been aphorized in Théodore Flournoy's From India to the Planet Mars (1899) from a longer quote by the French mathematician and astronomer Pierre-Simon Laplace as the Principle of Laplace: "The weight of the evidence should be proportioned to the strangeness of the facts." He noted that science's predictive power distinguished it from pseudoscience: "If you want to know when the next eclipse of the Sun will be, you might try magicians and mystics, but you'll do much better with scientists. They will tell you where on Earth to stand, when you have to be there, and whether it will be a partial eclipse, a total eclipse, or an annular eclipse. They can routinely predict a solar eclipse, up to the minute, a century in advance. You can go to the witch doctor to lift the spell that causes your pernicious anemia, or you can take Vitamin B12. If you want to save your child from polio, you can pray or you can inoculate."
=== Other interests === In his later years, Sagan proposed organizing a search for near-Earth objects (NEOs) that might impact the Earth but postponing the development of the technological methods needed to defend against them. He argued that all of the numerous methods proposed to alter the orbit of an asteroid, including the employment of nuclear detonations, created a deflection dilemma: if the ability to deflect an asteroid away from the Earth exists, then one would also have the ability to divert a non-threatening object towards Earth, creating an immensely destructive weapon. In a 1994 paper he co-authored, he ridiculed a three-day-long "Near-Earth Object Interception Workshop" held by Los Alamos National Laboratory (LANL) in 1993 that did not, "even in passing" state that such interception and deflection technologies could have these "ancillary dangers." Sagan remained hopeful that the natural NEO impact threat and the intrinsically double-edged essence of the methods to prevent these threats would serve as a "new and potent motivation to maturing international relations." Later acknowledging that, with sufficient international oversight, in the future a "work our way up" approach to implementing nuclear explosive deflection methods could be fielded, and when sufficient knowledge was gained, to use them to aid in mining asteroids. His interest in the use of nuclear detonations in space grew out of his work in 1958 for the Armour Research Foundation's Project A119, concerning the possibility of detonating a nuclear device on the lunar surface. He was an advocate for basic research, pointing out that it might prove to have practical applications in the future: "Maxwell wasn't thinking of radio, radar, and television when he first scratched out the fundamental equations of electromagnetism; Newton wasn't dreaming of space flight or communications satellites when he first understood the motion of the Moon; Roentgen wasn't contemplating medical diagnosis when he investigated a penetrating radiation so mysterious he called it 'X-rays'; Curie wasn't thinking of cancer therapy when she painstakingly extracted minute amounts of radium from tons of pitchblende; Fleming wasn't planning on saving the lives of millions with antibiotics when he noticed a circle free of bacteria around a growth of mold; Watson and Crick weren't imagining the cure of genetic diseases when they puzzled over the X-ray diffractometry of DNA…"
=== Sagan's number === Sagan's number is the number of stars in the observable universe. This number is reasonably well defined, because it is known what stars are and what the observable universe is, but its value is highly uncertain.
In 1980, Sagan estimated it to be 10 sextillion in short scale (1022). In 2003, it was estimated to be 70 sextillion (7 × 1022). In 2010, it was estimated to be 300 sextillion (3 × 1023).
=== "Billions and billions" === After Cosmos aired, Sagan became associated with the catchphrase "billions and billions", although he never actually said it. He rather used the term "billions upon billions." Richard Feynman used the phrase "billions and billions" many times in his Lectures on Physics. However, Sagan's frequent use of the word billions and distinctive delivery emphasizing the "b" (which he did intentionally, in place of more cumbersome alternatives such as "billions with a 'b'", in order to distinguish the word from "millions") was spoofed by Johnny Carson. Sagan was a friend of Carson's and a frequent guest on the Tonight Show. Other comedians followed Carson's lead, including Gary Kroeger, Mike Myers, Bronson Pinchot, Penn Jillette, Harry Shearer, and others. Frank Zappa satirized the line in the song "Be in My Video". Sagan took this all in good humor, and his final book was titled Billions and Billions, which opened with a tongue-in-cheek discussion of this catchphrase, observing that Carson was an amateur astronomer and that Carson's comic caricature often included real science. In 1993, engineers at Apple Computer code-named the Power Macintosh 7100 "Carl Sagan" in the hope that Apple would make "billions and billions". The name was only used internally, but Sagan was concerned that it would become a product endorsement and sent Apple a cease-and-desist letter. Apple complied, but engineers retaliated by changing the internal codename to "BHA" for "Butt-Head Astronomer." In November 1995, after further legal battle, an out-of-court settlement was reached and Apple's office of trademarks and patents released a conciliatory statement that "Apple has always had great respect for Dr. Sagan. It was never Apple's intention to cause Dr. Sagan or his family any embarrassment or concern." As a humorous tribute to Sagan and his association with the catchphrase "billions and billions", a sagan has been defined as a unit of measurement equivalent to a very large number of anything.