[...] The apparent rarity of technological civilizations begs for an explanation. One possibility arises from considering the chemical enrichment of the galaxy. All life on Earth, and indeed any conceivable extraterrestrial biochemistry, depends on elements heavier than hydrogen and helium--principally, carbon, nitrogen and oxygen. These elements, produced by nuclear reactions in stars, have gradually accumulated in the interstellar medium from which new stars and planets form. In the past the concentrations of these elements were lower--possibly too low to permit life to arise. Among stars in our part of the galaxy, the sun has a relatively high abundance of these elements for its age. Perhaps our solar system had a fortuitous head start in the origins and evolution of life.

But this argument is not as compelling as it may at first appear. For one, researchers do not know the critical threshold of heavy-element abundances that life requires. If abundances as low as a tenth of the solar value suffice, as seems plausible, then life could have arisen around much older stars. And although the sun does have a relatively high abundance of heavy elements for its age, it is certainly not unique [see "Here Come the Suns," by George Musser; SCIENTIFIC AMERICAN, May 1999]. Consider the nearby sunlike star 47 Ursae Majoris, one of the stars around which a Jupiter-mass planet has recently been discovered. This star has the same element abundances as the sun, but its estimated age is seven billion years. Any life that may have arisen in its planetary system should have had a 2.5-billion-year head start on us. Many millions of similarly old and chemically rich stars populate the galaxy, especially toward the center. Thus, the chemical evolution of the galaxy is almost certainly not able to fully account for the Fermi Paradox. [...]

L'Express, le 1/6/2000, (p. 29)
(Extrait)

L’Express, 6/1/2000 (p. 29)
(Excerpt)

La crisis producida por el vertido del Prestige, como hace algún tiempo los casos de las denominadas vacas locas, el accidente de Aznalcóllar con sus consecuencias para el ecosistema de Doñana o los posibles efectos de radiaciones electromagnéticas, ha sacado a la palestra, una vez más, la cuestión de la ciencia en España. Es inevitable que sea así, aunque no sea el mejor escenario para una discusión cabal del papel de la ciencia en un país en el que tal discusión se intensifica precisamente en momentos de desgracias, en situaciones de crisis.

Es absolutamente cierto que, citando algunas manifestaciones aparecidas estos días, España es “un país de poca ciencia”, o que “la existencia de una comunidad científica fuerte e independiente es un elemento clave para resolver los problemas que plantea de forma repetida nuestro mundo moderno”. Sí, es cierto que vivimos en un mundo cuyas características hacen que sea imprescindible poseer extensos “depósitos” de conocimientos científicos. Más aún, que vivimos en un mundo penetrado por la ciencia y la tecnología en tal medida que aumenta nuestra indefensión cuanto menor es nuestro grado de familiaridad con esa ciencia y esa tecnología. Hay evidentemente que escuchar a los científicos y dar la bienvenida o exigir su ayuda y conocimientos, más aún en momentos de crisis. Pero al mismo tiempo hay que tener muy claras algunas ideas acerca de lo que es y lo que puede ofrecer la ciencia, a la que yo considero, me apresuro a señalar, la mayor fuerza liberadora a disposición de la especie humana; liberadora de errores, mitos, servidumbres y limitaciones físicas (aunque no debemos olvidar otros, como la idea de justicia). La ciencia es, en efecto, el mejor instrumento que poseen los humanos para resolver problemas relacionados con la naturaleza que les rodea, pero la ciencia no puede resolver todos los problemas. O dicho de otra forma: no todos los problemas tienen solución, o no lo tienen en el lapso de tiempo que sería necesario para evitar algunos de los problemas que a veces afectan, de repente o no, a la sociedad, problemas como pueden ser los agujeros de la capa de ozono o el sida. [...]

Si esto no se comprende, si no se sabe que la ciencia es un instrumento maravilloso de conocimiento y de actuación, pero que tiene sus límites y sus tiempos propios y variables, puede suceder que haya quienes se sientan engañados al comprobar, en situaciones de crisis social, cuando desesperadamente necesitan soluciones, que éstas no llegan tan pronto y eficazmente como creían o como algunos les habían inducido a pensar. Y que entonces surja algún tipo de resquemor ante la ciencia. Sería un grave error: ¿piensa alguien que el que la ciencia no haya sido capaz todavía de erradicar el cáncer o el sida significa que la solución provendrá de algún otro tipo de “conocimiento”? En el caso de los agujeros de ozono, por ejemplo, ¿habríamos sido capaces de darnos cuenta de su existencia, causas y forma de combatirlo sin la ciencia?

The crisis caused by the oil spill of the Prestige, similarly to the cases of the "mad cows", the Aznalcσllar mine accident with its consequences on the ecosystem of Doρana, or the possible effects of electromagnetic radiation, has once again brought to the arena the issue of science in Spain. It is inevitable to talk about science, although this is not the best occasion for an accurate discussion on the role of science in a country where such a discussion intensifies precisely at times of misfortune and in crisis situations.

It is absolutely true that -quoting some manifestations that occurred recently- Spain is “a country of little science”, or “the existence of a strong and independent scientific community is a key element for solving the problems that our modern world creates repeatedly”. Yes, it is true that we live in a world whose characteristics require that we have extensive “deposits” of scientific knowledge. What's more, it is true that we live in a world penetrated by science and technology to such an extent that the less familiar we are with this science and technology, the more defenceless we become. It is clearly necessary to listen to scientists and welcome -or even demand- their help and knowledge, all the more so at times of crisis. But at the same time it is necessary to have a very clear idea of what science is and what it can offer, this science which I consider -as I am anxious to point out- the greatest liberating force available to the human species; it liberates us from errors, myths, subjections, and physical limitations (although we must not forget other things such as the notion of justice). Science is, in fact, the best tool that humans possess in order to solve problems related to the nature that surrounds them, but science cannot solve all problems. In other words, not all problems have a solution, or they don't have one in the time period that would be needed to avoid some of the problems that often affect society (whether that happens suddenly or not), such as the holes in the ozone layer, or AIDS. [...]

If people don't understand, if they don't know that science is a wonderful instrument of knowledge and intervention but which has its limits and its own variable time, it is possible that there will be some of them who will feel deceived when they realise, in situations of social crisis when they desperately need solutions, that these solutions do not come very quickly and effectively as they believed, or as some had led them to think. And then some kind of resentment may arise towards science. This would be a big mistake; does anybody really think that the fact that science has not yet been able to eradicate cancer or AIDS means that the solution will come from some other type of "knowledge"? In the case of the ozone holes, for example, would we have been able to notice their existence, their causes, and the way to fight the problem, without science?