Advanced Search Filters
Filter search results by source, date, and more with our premium search tools.
" "Carbonaceous meteorites that fall to the Earth... have several percent to as much as 10 percent of complex organic matter in them.
Carl Edward Sagan (9 November 1934 – 20 December 1996) was an American astronomer, planetary scientist, cosmologist, astrophysicist, astrobiologist, author, and science communicator. His best known scientific contribution is research on extraterrestrial life, including experimental demonstration of the production of amino acids from basic chemicals by radiation. Sagan assembled the first physical messages sent into space, the Pioneer plaque and the Voyager Golden Record, universal messages that could potentially be understood by any extraterrestrial intelligence that might find them. Sagan argued the hypothesis, accepted since, that the high surface temperatures of Venus can be attributed to, and calculated using, the greenhouse effect. He testified to the US Congress in 1985 that the greenhouse effect will change the earth's climate system.
Biography information from Wikiquote
Filter search results by source, date, and more with our premium search tools.
Related quotes. More quotes will automatically load as you scroll down, or you can use the load more buttons.
Incidentally, I find that reasonably good insights can be remembered the next day, but only if some effort has been made to set them down another way. If I write the insight down or tell it to someone, then I can remember it with no assistance the following morning; but if I merely say to myself that I must make an effort to remember, I never do. I find that most of the insights I achieve when high are into social issues, an area of creative scholarship very different from the one I am generally known for.
Enjoy ad-free browsing, unlimited collections, and advanced search features with Premium.
One consequence of this train of argument is that, even if civilizations commonly arise on planets throughout the Galaxy, few of them will be both long-lived and nontechnological. Since hazards from asteroids and comets must apply to inhabited planets all over the Galaxy, if there are such, intelligent beings everywhere will have to unify their home worlds politically, leave their planets, and move small nearby worlds around. Their eventual choice, as ours, is spaceflight or extinction.