EXOPLANETS

Left, explanation. (U/California). At the telescope, we measure the change in the wavelength (color) of light coming from a star over the course of days, months, and years. This changing wavelength is the Doppler shift of the light, resulting from the star orbiting a common center of mass with a companion planet. For example, Jupiter's gravitational pull causes the Sun to wobble around in a circle with a velocity of 12 meters per second.

Thanks to analysis of oscillations of light (radial velocity method/doppler shift due to stellar wobble), coming from suns different to our, induced by appearances and disappearances of celestial bodies orbiting around them, has been possible to document the existence -since 1991 to the date- of around 300 exoplanets. A fact that has allowed to David Bennett (U/Notre Dame), , to calculate that for each 2 present suns in our galaxy, exists at least 1 exoplanet, with what it would exist around 50 billion planetary systems alone in our Milky Way. An amazing number that favors the possibility of existence of life outside of our planetary system. Nevertheless the data regarding this last declaration, are not good. Most of discovered exoplanets to the date are gassy, inhospitable and orbit very near their suns, being for that denominated "hot Jupiter". Nevertheless, another group of scientists adduces that the littleness and scarce glow of many exoplanets, prevent to discover them with the current technology.

Exoplanet search has facilitated meanwhile, to discover extrasolar systems with up to 7 exoplanets (55 Cancri System). Some exoplanets has been silent witness and resisted the hot expansions of their stars about to collapse for exhaustion of its internal helium. Other stayed frozen at certain distance of their suns. Other, superhot goes losing its gassy atmosphere, as long as they orbit near its sun. Some scientists have seen the genesis of some exoplanets to the interior of accretion disks. The European satellite Corot, and the NASA, have begun recently an aggressive program of exoplanet search with the last aim of identifying planets similar to ours, able to harbor life.

EXOPLANETAS

Merced a análisis de oscilaciones de la luz (método de velocidad radial/doppler shift due to stellar wobble), procedentes de soles distintos al nuestro, inducidas por apariciones y desapariciones de cuerpos celestes orbitantes alrededor de ellos, ha sido posible documentar la existencia -desde 1991 a la fecha- de alrededor de unos 300 exoplanetas. Un hecho que le ha permitido a David Bennett (U/Notre Dame), calcular que por cada 2 soles presentes en nuestra galaxia, existe al menos 1 exoplaneta, con lo que existirían alrededor de 50 billones de sistemas planetarios solo en la en la Via Láctea. Una barbaridad, que favorece la posibilidad de existencia de vida fuera de nuestro sistema planetario. No obstante los datos respecto a este ultimo aserto, son desalentadores. La mayoría de exoplanetas descubiertos a la fecha son gaseosos, inhóspitos y orbitan muy cerca de sus soles, siendo por ello denominados “Jupiter calientes”. No obstante, otro grupo de científicos aduce que la pequeñez y brillo escaso de muchos exoplanetas, impide descubrirlos con la tecnología actual.

La búsqueda de exoplanetas ha posibilitado mientras tanto, descubrir sistemas extrasolares con hasta 7 exoplanetas (55 Cancri System). Algunos exoplanetas han sido mudos testigos y resistido expansiones y calentamientos de sus estrellas a punto de colapsar por agotamiento de su helio interno. Otros se mantienen helados a cierta distancia de sus soles. Otros, supercalientes van perdiendo su atmósfera gaseosa, en tanto orbitan cerca de su sol. Algunos científicos han visibilizado incluso, la génesis misma de algunos exoplanetas al interior de discos de acreción. El satelite europeo Corot, y la NASA, han iniciado recientemente un agresivo programa de identificación de exoplanetas, con el fin último de identificar planetas semejantes al nuestro, capaces de albergar vida.

EXOPLANETS

http://es.youtube.com/watch?v=M63XDXZp2Jc

1) With the discovery of the exoplanets (but there of the solar system): Wasp 1,2,3,4,5, for scientific of the Qeen's University/Belfast these already add, until today (October/2007) : 263, being expected be 1000 at the end of the 2010, in reason of the development of better telescopes and better understanding of the influence of their gravitational fields and physical interference (partial eclipses) etc, with their respective suns. With which definitions of planets, exoplanets and interstellar planets (don't orbit around any sun), emerge now with enough solidity.

2) One of the biggest problems to detect exoplanets is that their size and light, are a lot of minor that that of the stars around which they orbit, hindering to see them directly, fact that paradoxically stimulates the logic and astronomers' imagination dedicated to its search. Today, these exoplanets are being discovered in greater number, thanks to: a) the developing of powerful telescopes capable of scan permanently the whole Universe (Corot, SuperWasp System, etc., and b) detection of the same ones for indirect methodology: seen from the Earth ; when the exoplanet (mostly giant gassy planets similar to Jupiter), pass before their stars, a decrease of its brightness is generated which help todetermine the size of the exoplanet and of its star, generating changes in the position and star's speed, allowing to carry out calculations of the size of the exoplanet and of its distance to its star. This method and other, allow at the moment alone to discover big, hot planets (emit intense infrared radiation) and broadly separated from their stars.

Although great number of discovered exoplanets, orbit its respective stars in a couple of days (contrary to the Earth that needs 1 year) and have little chance of harboring life (superficial temperatures of but of 2000 C), others like the Gliese 581 d, the third planet that orbits to the red dwarf star 581 (20 years light of the Earth), could harbor life as long as this planet orbit a similar habitable area to that of Earth.

EXOPLANETAS

1) Tras el descubrimiento de los exoplanetas (mas alla del sistema solar) : Wasp 1,2,3,4,5, por Cientificos del Qeen's University/Belfast estos suman ya, hasta hoy (10/2007), 263, esperándose se quintupliquen hasta fines del 2010, en razón del desarrollo de mejores telescopios y una mejor comprensión de la influencia de sus campos gravitatorios e interferencias físicas (eclipses), etc, con sus respectivos soles.Con lo que las definiciones de planetas, exoplanetas y planetas interestelares (no orbitan alrededor de ningún sol), emergen ahora con bastante solidez.

2) Uno de los mayores problemas para detectar exoplanetas es que su tamaño y luz, son muchísimo menores que el de las estrellas alrededor de la cuales orbitan, dificultando verlas directamente, lo que paradójicamente estimula la lógica e imaginación de astrónomos dedicados a su búsqueda. Hoy, estos exoplanetas están siendo descubiertos en mayor numero, merced a: a) desarrollo de poderosos telescopios capaces de escanear permanentemente todo el Universo (Corot, Wasp System, etc y b) detección de los mismos por metodología indirecta :vistas desde la Tierra, cuando el exoplaneta (mayormente gigantes de gas similares a Jupiter), pasan delante de sus estrellas, se genera una disminución de la luminosidad de estas ultimas, dependiente del tamaño del exoplaneta y de su estrella, generando cambios en la posición y velocidad de la estrella, permitiendo realizar cálculos del tamaño del exoplaneta y de su distancia a su estrella. Este metodo y otros, permiten por el momento solo descubrir planetas grandes, calientes (emiten intensa radiación infraroja) y ampliamente separados de sus estrellas.

3) Aunque gran numero de los exoplanetas descubiertos, orbitan sus respectivas estrellas en 1 par de días (a diferencia de la Tierra que necesita 1 año) y tienen poca chance de albergar vida (temperaturas superficiales de mas de 2000 C), otros como el Gliese 581 d, el tercer planeta que orbita a la estrella enana roja Gliese 581 (a 20 años luz de la Tierra), podría albergar vida en tanto orbita una zona habitable similar a la de la Tierra.

WATER in GIANT EXOPLANETS.

http://es.youtube.com/watch?v=Xt3L71uI4nc

Although some astronomers think that results are consequence of instrumental faults, Giovanna Tinnetti and colleagues (UCLA, Institute d'Astrophysique of Paris, ESA, University College London), said they have obtained the most convincing test of presence of water steam in the atmosphere of a hot planet: HD 189733b (giant planet, orbiting very close around its star -in this case- To = 930 oC, by day/427 oC at night, located in the Constellation of Vulpecula, to 64 years light of our Solar System). The news has 2 commentaries from us: 1) Sean Carey, coauthor of the study (published in Nature), says that previously they had developed spectrographic fingerprints of the atmosphere of several exoplanets, with help of NASA's Spitzer Spatial Infrared Telescope, obtaining almost always a vertical isothermal profile in hot planets. Also, Jonathan Tensión and colleagues developed models and formulas to signal water presence in the spectral analysis. Tinetti and colleagues who study atmospheric signatures, have more than 500 000 individual data of absorption of light, with which they calculated the basic parameters of absorption for temperature and atmospheric water. The researchers concentrated themselves in certain dark areas (of the atmosphere of the hot planet), while it journeyed nearly its star. The variations of the effective radius of the hot planet, dependent of different wavelengths (3,6 ms - 5,8 ms and 8, 5 ms), were interpreted as secondary to water steam presence in the atmosphere of the hot planet. In these cases, the effective radius of the planet shines but great to wavelengths compatible with atmospheric water presence. Now it is said that water steam is common in: Jupiter, Saturn, Urano and Neptune, with which the possibility of extrasolar life is not dead.

2) On the other side impress us, the quality of data caught by the Spitzer, that cooled cryogenically (5.5 K), follows an heliocentric orbit, persecuting the Earth, with which is possible to study the most distant objects of universe. The Spitzer weighs 950 kgs, stores 360 liters of liquid Helium, measures 0,85 m and reads images of between 3 to 180 microns. Sent in August of the 2003, it has an average life of 5 years. With some angular limitations the Spitzer is able to provide a great instantaneous vista of the sky. Their mirrors and structures of support, are made almost in their totality of Beryllium. 3) The third thing is the maximization of the potential of the human eye, expanded every time at incommensurable levels. From the initial inverted natural images rearranged in our brain, one has gone to do without this sense, replacing it with thermal, luminance, chemical, physical perceptions, interpretations of oscillations of wavelengths, etc –like in this case- or others, that in the end provide similar perceptions to the human eye. Although at the end, the impressive thing is the use of the logic, statistic, valuation of evidences collected by our humble brains, etc., to make the respective correlations and the final interpretation.

Habitable Exo-Super Earth?

http://www.youtube.com/watch?v=PmTjAmop688

The news of the discovery of a Super Earth (exo-planet 581c, similar to ours), something but big (5 times, but mass), completing full orbits in 13 days, around their dwarf red star (Gliese 581), 100 times less luminous and colder than our Sun, with possibilities of housing water and life (Alison Boyle, Curator of Astronomy London's Science Museum), reopens the debate around the possible existence of extraterrestrial life. The system Gliese 581, distant 20, 5 years-light of our solar system, located in the constellation of Libra, has 2 additional planets: 1 of 15 and another of 8 times the size of the Earth orbiting but close and but far from their sun, respectively. The exoplanet Super Earth, was identified by an advanced spectrógraph associated to a telescope of 3,6 m of European Southern Observatory (ESO), in La Silla, Desert of Atacama/Chile, while the exoplanet carried out wobbling movements around its star. The exoplanet, is the but small of other 200 that can house life. These mostly look like to giant Jupiter full of gases and high temperatures caused by their orbit near their sun, a great impediment to life. With hardly 1 or 2 evidences, we are surprised that most scientific media labeled as habitable planet to Gliese 581c. For what we recommend to whom interests to revise critically, 2 seminal articles, published in the Scientific American (1-Carl Sagan, 1994: The Search for Extraterrestrial Life. 2 - Carl Sagan and Frank Draje, 1997: The Search for Extraterrestrial Intelligence. Although could exist another forms of life with solvent different to water (NH3), different backbone elements (Silicon, instead of C) and different metabolic processes (cold enzymes), examining the Earth since the high thing (Galileo Mission), Sagan demands (at least for existence of organic life), the following astrobiologic evidences:

1. Sun of moderate size with strong and stable radiation. Exoplanets, with orbits almost circular at uniforms distances of their suns. Although the sun of the System Gliese 581, is less luminous and small, it compensates their smallest brightness with their biggest proximity (14 times but), to its sun, getting ready so that the exoplanet possesses among 0-40 Centigrade grades, enough to be located in the habitable zone (area around a sun, where it can be generated liquid water in the surface of a planet). "How hot is a planet”, Stéphane Udry, from Geneva Observatory (Switzerland) and lead-author of the paper reporting the result says “depends on all light it reflects." Under these conditions a planet should be rocky as the Earth or covered by oceans (Dimitar Sasselov of the Harvard-Smithsonian Center for Astrophysics). To this loner evidences, the supposedly SuperEarth, lacks others, like :
2-Abundance of molecular oxygen. As it is known data of Galileo Mission that studied the Earth, gave bill of a strong decrease of the brightness in a region (0,76 microns), near to the infrared, wave longitude in which the molecular oxygen absorbs radiation, demonstrating their abundance in the earth atmosphere (but that in another solar planet), comprehensible alone for alive (photosynthesis in plants) beings' activity.
3-The work doesn't demonstrate abundance of organic (C, N, H) molecules. The presence of water is suggested, not demonstrated,
4-The work doesn't speak of methane presence. The infrared spectrometer of Galileo Mission detects traces (1 part for million of methane), in the Earth in imbalance with oxygen. In reality, should not exist any methane molecule in the atmosphere. Alone some unusual (bacterial metabolism in ruminant and termites) processes, generates methane.
5 -When Galileo Mission photographed the Earth discovered a band of sharp (0,7 microns) absorption, able to absorb photons of visible light, present in most of continents. It was the Chlorophyll not mentioned in the work.
6-Finally Galileo Mission detects orderly radio waves of short band, coming from the Earth, characteristic of a technological civilization, neither discussed in the article.

Exo SuperTierra, habitable?.

La noticia del descubrimiento de Super Tierra (exo-planeta 581c, semejante al nuestro), algo más grande (5 veces, más masa), completando órbitas totales en 13 dias, alrededor de su enana estrella roja (Gliese 581), 100 veces menos luminosa y mas fria que nuestro Sol, con posibilidades de albergar agua y vida (Alison Boyle, Curator del Astronomy London's Science Museum), reabre el debate en torno a la posible existencia de vida extraterrestre. El sistema Gliese 581, distante 20, 5 años luz de nuestro sistema solar, ubicado en la constelación de Libra, cuenta con 2 planetas adicionales : 1 de 15 y otro de 8 veces el tamaño de la Tierra orbitando mas cerca y mas lejos de su sol, respectivamente. El exoplaneta Super Tierra, fué identificado con un avanzado espectrógrafo asociado a un telescopio de 3,6 m del European Southern Observatory (ESO), en La Silla, Desierto de Atacama/Chile, mientras realizaba movimientos oscilantes alrededor de su estrella. El exoplaneta, es el más pequeño de otros 200 que pudiesen albergar vida. Estos mayormente semejan al gigante Jupiter pleno de gases y altas temperaturas causadas por su orbitar cercano al sol, inhabilitador de vida. Con apenas 1 o 2 evidencias a nosotros nos sorprende el etiquetado de planeta habitable reportado en la mayoria de medios cientificos. Por lo que recomendamos a quien le interese revisar criticamente, 2 articulos seminales, publicados en el Scientific American (1-Carl Sagan, 1994: The Search for Extraterrestrial Life 2- Carl Sagan y Frank Draje, 1997:The Search for Extraterrestrial Intelligence. Aunque pudiesen existir formas de vida con solventes distintos al agua (NH3), elementos estructurales distintos al C (Silicio) y procesos metabólicos diferentes (enzimas en frio), examinando desde lo alto (Misión Galileo), a la Tierra, Sagan exige (al menos para la existencia de vida organica), las siguientes evidencias astrobiologicas: 1. Sol de tamaño moderado con radiación fuerte y estable. Exoplanetas, con órbitas casi circulares a distancias uniformes del sol. Aunque el sol del Sistema Gliese 581, es mas frio y pequeño, compensa su menor luminosidad con su mayor cercania (14 veces mas), a su sol, arreglándoselas para que el exoplaneta posea entre 0-40 grados Centigrados, suficiente para ubicarse en la franja habitable (area alrededor de un sol, donde puede generarse agua liquida en la superficie de un planeta). “Cuan caliente esté un planeta", dice la Dra Stéphane Udry, del Geneva Observatory (Suiza) y autora principal del trabajo reportandolos resultados "depende de cuanta luz refleje”. En estas condiciones un planeta deberia ser rocoso como la Tierra o cubierto por oceanos (Dimitar Sasselov del Harvard-Smithsonian Center for Astrophysics). A esta solitaria evidencia, le faltan otras, como :

2-Abundancia de oxigeno molecular planetario. Como se sabe datos de la Misión Galileo que estudiaba la Tierra, dieron cuenta de una fuerte disminución de la brillantéz de una región (0,76 micrones), cercana al infrarrojo, longitud de onda en la cual el oxigeno molecular absorbe radiación, demostrando su abundancia en la atmósfera terrestre (mas que en otro planeta solar), comprensible solo por actividad de seres vivientes (fotosíntesis en plantas).

3-El trabajo no demuestra abundancia de moléculas orgánicas (C,N,H,). La presencia de agua es sugerida, no demostrada.

4-El trabajo no habla de la presencia de metano. El espectrometro infrarojo del Galileo detectó trazas (una parte por millon de metano), en la Tierra en desequilibrio con el oxigeno. No debiese existir ninguna molécula de metano en la atmósfera. Solo algunos procesos inusuales (metabolismo bacteriano en rumiantes y termitas), genera metano.

5- Cuando el Galileo fotografióla Tierra descubrióuna banda de absorción aguda (0,7 micrones), capaz de absorber fotones de luz visible, presente en la mayoria de continentes. Se trataba de la Clorofila no mencionada en el trabajo.

6-Finalmente la Misión Galileo detectó ondas ordenadas de radio de banda corta, procedentes de la Tierra, propias de una civilización tecnológica, tampoco discutidas en el articulo.