Astronomía (Continuación)

ReflexionesPensamiento, Cultura y Ciencia

Astronomers announced last month that, contrary to previous assumptions, the orbiting body Eris might be smaller than Pluto after all. Since it was the discovery in 2005 of Eris, an object seemingly larger than what had been considered our smallest planet, that precipitated the downgrading of Pluto from full planet to “dwarf”, some think it may be time to revisit Pluto’s status.

Most of us can’t help rooting for Pluto. We liked the idea of a ninth planet, hanging out there like a period at the end of the gorgeous sentence of the solar system. It gave us a sense of completeness.…  Seguir leyendo »

ReflexionesPensamiento, Cultura y Ciencia

In a great many fields, researchers would give their eyeteeth to have a direct glimpse of the past. Instead, they generally have to piece together remote conditions using remnants like weathered fossils, decaying parchments or mummified remains. Cosmology, the study of the origin and evolution of the universe, is different. It is the one arena in which we can actually witness history.

The pinpoints of starlight we see with the naked eye are photons that have been streaming toward us for a few years or a few thousand. The light from more distant objects, captured by powerful telescopes, has been traveling toward us far longer than that, sometimes for billions of years.…  Seguir leyendo »

ReflexionesPensamiento, Cultura y Ciencia

What is the winter solstice, and why bother to celebrate it, as so many people around the world will tomorrow? The word “solstice” derives from the Latin sol (meaning sun) and statum (stand still), and reflects what we see on the first days of summer and winter when, at dawn for two or three days, the sun seems to linger for several minutes in its passage across the sky, before beginning to double back.

Indeed, “turnings of the sun” is an old phrase, used by both Hesiod and Homer. The novelist Alan Furst has one of his characters nicely observe, “the day the sun is said to pause.…  Seguir leyendo »

ReflexionesPensamiento, Cultura y Ciencia

A few weeks ago, an asteroid almost 30 feet across and zipping along at 38,000 miles per hour flew 28,000 miles above Singapore. Why, you might reasonably ask, should non-astronomy buffs care about a near miss from such a tiny rock? Well, I can give you one very good reason: asteroids don’t always miss. If even a relatively little object was to strike a city, millions of people could be wiped out.

Thanks to telescopes that can see ever smaller objects at ever greater distances, we can now predict dangerous asteroid impacts decades ahead of time. We can even use current space technology and fairly simple spacecraft to alter an asteroid’s orbit enough to avoid a collision.…  Seguir leyendo »

ReflexionesPensamiento, Cultura y Ciencia

Einstein averred that “the most incomprehensible thing about the Universe is that it is comprehensible”. He was right to be astonished. Our minds evolved to cope with life on the African savannah, but can comprehend a great deal about the counterintuitive microworld of atoms, and about the vastness of the cosmos.

Indeed, Einstein would have been specially gratified at how our cosmic horizons have expanded. Our Sun is one of a hundred billion stars in our galaxy, which is itself one of many billion of galaxies in range of our telescopes. And there is firm evidence that these all emerged from a hot dense “beginning” nearly 14 billion years ago.…  Seguir leyendo »

ReflexionesPensamiento, Cultura y Ciencia

Le monde va devoir prendre une décision importante en 2010. Anatoly Perminov, responsable de l’Agence spatiale russe Roscosmos, propose d’envoyer une mission inhabitée pour détourner un gros astéroïde qui pourrait entrer en collision avec la Terre après 2030.

Avec un diamètre de plus de 360 mètres, l’astéroïde Apophis est douze fois plus gros que l’objet céleste Tunguska (dont on pense que c’était une météorite ou une comète) qui ravageat une grande part de l’est sibérien il y a un siècle. Les recherches ont permis de déterminer que l’objet a éclaté le 30 juin 1908 avec une force équivalente à celle d’une arme nucléaire, déracinant quelque 80 millions d’arbres sur une zone de plus de 2000 kilomètres carrés.…  Seguir leyendo »

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Sócrates, nacido a finales del siglo IV en Constantinopla, cuenta, en el libro séptimo de su Historia de la Iglesia, lo que le sucedió a la hija de Theon, Hypatía de Alejandría, que, habiendo hecho acopio de gran erudición, superaba con mucho a los filósofos de su tiempo; platónica según la escuela de Plotino, instruía a numerosos estudiantes. Y por su ciencia, autoridad, prestigio y modestia, comparecía en instancias de la administración pública; de ahí el que, a la par que respeto, su proximidad a las autoridades levantara suspicacias. En efecto, la envidia, por un lado, y el hecho, por otro, de verla conversar frecuentemente con Orestes, prefecto imperial, enfrentado con Cirilo, el obispo, dio pie a que se hiciera circular, entre los cristianos, la especie de que era ella la que impedía la reconciliación entre ambos, cosa que Sócrates califica de falsa acusación.…  Seguir leyendo »

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Entre Cleopatra y Justine, la antigua reina y el personaje moderno de Lawrence Durrell, está Hypatia, la otra gran alejandrina. Juntas, las tres mujeres representan perfectamente el alma de Alejandría, la capital de los Ptolomeos -con los inigualables Biblioteca y Museo, el alto Faro y el Soma, la resplandeciente tumba del fundador, Alejandro Magno- pero también la ciudad arruinada de innumerables calles en las que se arremolina el polvo de la historia, la ciudad de las rencillas religiosas, la decrépita y melancólica del Viejo (Kavafis), la ciudad recreada por E. M. Forster, la ciudad, en fin, "de las cinco razas, cinco lenguas, una docena de religiones, el reflejo de cinco flotas en el agua grasienta, más allá de la escollera, pero con más de cinco sexos", como la describió Durrell en su Cuarteto.…  Seguir leyendo »

ReflexionesPensamiento, Cultura y Ciencia

The Perseid meteor shower is summer’s closing act, arriving in mid-August like clockwork. For centuries, many Christians associated it with the martyred St. Lawrence, whose feast day falls on Aug. 10, so they called the display “the tears of St. Lawrence.” By the mid-1800s, the Italian astronomer Giovanni Schiaparelli came to understand that meteor showers are really comet dust — the “very minute particles that they have abandoned along their orbit.”

Meteor showers occur when Earth intersects with these so-called debris trains at particular times of the year. In the case of the Perseids, the meteor shower that peaks Wednesday and continues this week, the dust comes from Comet Swift-Tuttle, whose remains appear to shower down from the constellation Perseus as it moves across the northern sky.…  Seguir leyendo »

EspañaCultura y Ciencia

Estos días, con motivo del 40 aniversario de la llegada del hombre a la Luna, hemos rememorado momentos de gran belleza, emoción y heroísmo plasmados en las fotografías y secuencias filmadas por las cámaras del Apolo XI. Revisando la prensa de la época, encontramos otras imágenes históricas que retratan el entusiasmo y la expectación generada, en todo el mundo, con motivo de la misión espacial. Una de estas fotografías, publicada en el diario ABC en julio de 1969, nos muestra al Papa Pablo VI observando la luna a través «del potente telescopio del Observatorio de Castelgandolfo». Me serviré de esta escena para enmarcar dos acontecimientos igualmente históricos, ambos relacionados con la observación del cielo.…  Seguir leyendo »

ReflexionesPensamiento, Cultura y Ciencia

NASA this week unveils a new emissary in the search for evidence of extraterrestrial life. The Phoenix Mars Lander, which launches next month, marks just the latest instalment in a quest that has exercised the imaginations of writers and scientists since long before the adventures of Jules Verne. In the 17th century Johannes Kepler, the architect of our modern understanding of the solar system, imagined a journey to a moon inhabited by serpent-like creatures called Prevlovans who endured the lunar night "bristling with ice and snow under the raging, icy winds". Regrettably, however, here is no reliable account of a real encounter with alien life-forms.…  Seguir leyendo »

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Scientists are slowly waking up to an inconvenient truth - the universe looks suspiciously like a fix. The issue concerns the very laws of nature themselves. For 40 years, physicists and cosmologists have been quietly collecting examples of all too convenient "coincidences" and special features in the underlying laws of the universe that seem to be necessary in order for life, and hence conscious beings, to exist. Change any one of them and the consequences would be lethal. Fred Hoyle, the distinguished cosmologist, once said it was as if "a super- intellect has monkeyed with physics".

To see the problem, imagine playing God with the cosmos.…  Seguir leyendo »

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By Brian Greene, a professor of physics and mathematics at Columbia, is the author of “The Elegant Universe” and “The Fabric of the Cosmos” (THE NEW YORK TIMES, 20/10/06):

SEVENTY-FIVE years ago this month, The New York Times reported that Albert Einstein had completed his unified field theory — a theory that promised to stitch all of nature's forces into a single, tightly woven mathematical tapestry. But as had happened before and would happen again, closer scrutiny revealed flaws that sent Einstein back to the drawing board. Nevertheless, Einstein's belief that he'd one day complete the unified theory rarely faltered.…  Seguir leyendo »

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Por Rafael Bachiller, astrónomo, director del Observatorio Astronómico Nacional y representante nacional en la Asamblea de la UAI (EL MUNDO, 25/08/06):

Ayer, los astrónomos reunidos en Praga, en la Asamblea General de la Unión Astronómica Internacional (UAI), no hemos sido capaces de zanjar completamente el largo debate que se viene manteniendo durante varios años sobre qué es un planeta. A la asamblea hemos asistido unos 2.500 astrónomos de los más de 9.000 miembros de la UAI, procedentes de unos 75 países. Las discusiones mantenidas durante la asamblea han sido la continuación del procedimiento iniciado por la Unión cuando hace dos años formó un grupo de trabajo para definir de forma precisa el término planeta.…  Seguir leyendo »

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By Tim Kreider, a cartoonist, is the author of “The Pain: When Will It End?” and “Why Do They Kill Me?” (THE NEW YORK TIMES, 23/08/06):

MY love for our picked-on ninth planet is deeply, perhaps embarrassingly, personal.

I took my first public stand on Pluto’s taxonomical fate when I addressed the Forum on Outer Planetary Exploration in 2001 (don’t ask why a cartoonist was addressing astronomers — it’s a long story).

I informed the assembled scientists that, first of all, no way was I or anyone else about to un-memorize anything we’d already been forced to learn in elementary school.…  Seguir leyendo »

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By Dava Sobel, author of "Longitude," "Galileo's Daughter," and "The Planets," served as the sole non-scientist on the Planet Definition Committee (THE WASHINGTON POST, 16/08/06):

Pluto has become the butt of jokes lately, replacing Uranus as the solar system's laughingstock -- and all because scientists find themselves forced, at last, to come to terms with the meaning of the word "planet."

Tacit definitions have existed since ancient times, when planetai, meaning wanderers, applied to seven moving lights in the sky: the sun, the moon, Mercury, Venus, Mars, Jupiter and Saturn. But telescopes have revealed more objects in the solar system than were dreamt of in ancient philosophy, and new discoveries demand strict, useful terminology that will help astronomers categorize a host of newfound worlds.…  Seguir leyendo »

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By Mike Brown, a professor of planetary astronomy at the California Institute of Technology (THE NEW YORK TIMES, 16/08/06):

Pasadena, Calif.

LAST year, two colleagues and I announced that we had found an unknown body slightly larger than Pluto in the far reaches of our solar system. Since then, astronomical confusion has reigned on Earth and, depending on whom you ask, our solar system has 8, 9, 10 or, shockingly, 53 planets.

Next week, the International Astronomical Union, which oversees astronomical rules and conventions, will vote on a strict definition of “planet.” The result of that vote is hard to predict, but soon, we’ll likely lose a planet we’ve gotten to know for the past 76 years, or gain at least one more.…  Seguir leyendo »

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By Brian Marsden, an astronomer and the director of the Minor Planets Centre at Harvard University (THE GUARDIAN, 14/08/06):

It's time we admitted that accepting Pluto as the ninth planet was a big mistake. The announcement from the Lowell observatory in 1930 that a distant new planet had been found in accordance with the prediction by the observatory's founder was a brilliant exercise in public relations. Little heed was paid to critics who soon pointed out that the object was much smaller than Percival Lowell had claimed and that there was no way he could have made a meaningful prediction.…  Seguir leyendo »