In many fields of science, the imagination is only limited by the language that can explain it.
As we discovered nearly a year ago, forms of life could exist that play by rules beyond our base of knowledge.
Scientists know that it’s likely that they will discover many more planets orbiting distant stars. They also know that researchers are most likely to focus on those that exhibit Earth-like conditions, in an attempt to find life in another part of the universe.
But what if alien life can exist in conditions drastically unlike those of Earth? Will scientists mistakenly overlook them?
Driven by this fear — and the admission that searching for Earth-like conditions as a precondition for life is a basic but incomplete strategy for finding it — an international team of researchers from NASA, SETI and several universities are working to develop a classification system that includes chemical and physical parameters that are theoretically conducive to life, even if they result in decidedly un-Earth-like conditions.
Washington State University astrobiologist Dirk Schulze-Makuch, University of Puerto Rico modeling expert Abel Mendez and seven more colleagues have developed two different indices — an Earth Similarity Index that categorizes a planet’s more Earth-like features, and a Planetary Habitability Index that includes theoretical parameters — that they say can help researchers more easily find patterns in large and complex datasets.
It’s the first attempt by scientists to categorize the potential of exoplanets and exomoons to harbor life, and should prevent Earth-bound researchers from overlooking conditions that are, ahem, alien to them in their search for life.
Their work will be published in the December issue of the journal Astrobiology.
Autor...Andrew Nusca | November 21, 2011, 7:09 AM PST
en la publicacion Smart Planet Daily.
martes, 22 de noviembre de 2011
jueves, 17 de noviembre de 2011
Neuroscience Challenges Old Ideas about Free Will
Celebrated neuroscientist Michael S. Gazzaniga explains the new science behind an ancient philosophical question
By Gareth Cook | Tuesday, November 15, 2011 | 41
'''''''''''''''''''''''''''''''''''''''''''''''''''
Do we have free will? It is an age-old question which has attracted the attention of philosophers, theologians, lawyers and political theorists. Now it is attracting the attention of neuroscience, explains Michael S. Gazzaniga, director of the SAGE Center for the Study of the Mind at the University of California, Santa Barbara, and author of the new book, “Who’s In Charge: Free Will and the Science of the Brain.” He spoke with Mind Matters editor Gareth Cook.
Cook: Why did you decide to tackle the question of free will?
Gazzaniga: I think the issue is on every thinking person’s mind. I can remember wondering about it 50 years ago when I was a student at Dartmouth. At that time, the issue was raw and simply stated. Physics and chemistry were king and while all of us were too young to shave, we saw the implications. For me, those were back in the days when I went to Church every Sunday, and sometimes on Monday if I had an exam coming up!
Now, after 50 years of studying the brain, listening to philosophers, and most recently being slowly educated about the law, the issue is back on my front burner. The question of whether we are responsible for our actions -- or robots that respond automatically -- has been around a long time but until recently the great scholars who spoke out on the issue didn’t know modern science with its deep knowledge and implications.
Cook: What makes you think that neuroscience can shed any light on what has long been a philosophical question?
Gazzaniga: Philosophers are the best at articulating the nature of a problem before anybody knows anything empirical. The modern philosophers of mind now seize on neuroscience and cognitive science to help illuminate age old questions and to this day are frequently ahead of the pack. Among other skills, they have time to think! The laboratory scientist is consumed with experimental details, analyzing data, and frequently does not have the time to place a scientific finding into a larger landscape. It is a constant tension.
Having said that, philosophers can’t have all the fun. Faced with the nature of biologic mechanisms morning, noon, and night, neuroscientists can’t help but think about such questions as the nature of “freedom of action in a mechanistic universe” as one great neuroscientist put it years ago. At a minimum, neuroscience directs one’s attention to the question of how does action come about.
Cook: Do you think that neuroscience, as a field, needs to tackle these questions? That is, do you consider free will an important scientific question?
Gazzaniga: We all need to understand more about free will, or more wisely put, the nature of action. Neuroscience is one highly relevant discipline to this issue. Whatever your beliefs about free will, everyone feels like they have it, even those who dispute that it exists. What neuroscience has been showing us, however, is that it all works differently than how we feel it must work. For instance, neuroscientific experiments indicate that human decisions for action are made before the individual is consciously aware of them. Instead of this finding answering the age-old question of whether the brain decides before the mind decides, it makes us wonder if that is even the way to think about how the brain works. Research is focused on many aspects of decision making and actions, such as where in the brain decisions to act are formed and executed, how a bunch of interacting neurons becomes a moral agent, and even how one’s beliefs about whether they have free will affect their actions. The list of issues where neuroscience will weigh in is endless.
Cook: Please explain what you mean by the idea of an "emergent mind," and the distinction you draw between this and the brain?
Gazzaniga: Leibnitz raised the question almost 300 years ago with his analogy of the mill. Imagine that you can blow the mill up in size such that all components are magnified and you can walk among them. All you find are individual mechanical components, a wheel here, a spindle there. By looking at the parts of the mill you cannot deduce its function. The physical brain can also be broken into parts and their interactions examined. We now understand neurons and how they fire and a bit about neurotransmitters and so forth. But somehow the mental properties are indivisible and can’t be described in terms of neuronal firings. They need to be understood in another vocabulary.
This is sometimes called the emergent mind. Emergence as a concept in general is widely accepted in physics, chemistry, biology, sociology, you name it. Neuroscientists, however, have a hard time with it because they are suspicious that this concept is sneaking a ghost into the machine. That is not it at all. The motivation for this suggestion is to conceptualize the actual architecture of the layered brain/mind interaction so it can be properly studied. It is lazy to stay locked into one layer of analysis and to dismiss the other.
Cook: How does the mind constrain the brain?
Gazzaniga: No one said this is going to be easy and here is where the going gets tough. Picking up on the last thought the idea: we are dealing with a layered system, and each layer has its own laws and protocols, just like in physics where Newton’s Laws apply to one layer of physics and quantum mechanics to another. Think of hardware-software layers. Hardware is useless without software and software is useless without hardware.
How are we to capture an understanding how the two layers interact? For now, no one really captures that reality and certainly no one has yet captured how mental states interact with the neurons that produce them. Yet we know the top mental layers and the layers beneath it, which produce it, interact. Patients suffering from depression can be aided by talk therapy (top-down). They can also be aided by pharmacological drugs (bottom up). When these two therapies are combined the therapy is even better. That is an example of the mind constraining the brain.
Cook: And how does this idea of the mind and brain interacting bring you to your position on free will?
Gazzaniga: For me, it captures the fact that we are trying to understand a layered system. One becomes cognizant there is a system on top of the personal mind/brain layers which is yet another layer--the social world. It interacts massively with our mental processes and vice versa. In many ways we humans, in achieving our robustness, have uploaded many of our critical needs to the social system around us so that the stuff we invent can survive our own fragile and vulnerable lives.
Cook: You talk about “abandoning” the idea of free will. Can you explain what you mean by this, and how you came to this conclusion?
Gazzaniga: As I see it, this is the way to think about it: If you were a Martian landing on Earth today and were gathering information how humans work, the idea of free will as commonly understood in folk psychology would not come up. The Martian would learn humans had learned about physics and chemistry and causation in the standard sense. They would be astonished to see the amount of information that has accumulated about how cells work, how brains work and would conclude, “OK, they are getting it. Just like cells are complex wonderful machines, so are brains. They work in cool ways even though there is this strong tug on them to think there is some little guy in their head calling the shots. There is not.”
The world is not flat. Before this truth was realized, people use to wonder what happened when you got to the end of the earth-- did you fall off? Once we knew the earth was round, the new perspective, made us see how the old questions were silly. New questions also seem silly many times until a new perspective is accepted. I think we will get over the idea of free will and and accept we are a special kind of machine, one with a moral agency which comes from living in social groups. This perspective will make us ask new kinds of questions.
Cook: Are there particular experiments which you think have shed important light on the question of free will?
Gazzaniga: All of neuroscience in one way or another is shining light on how the brain works. That is the reality of it and it is that knowledge, slowly accumulating that will drive us to think more deeply. One way to get going on this is to try and answer the simple question. Free from what? What does anybody want to be free from? I surely do not want to be free from the laws of nature.
Cook: Do you think this science is going to force philosophers to change how they think about free will? And how about the rest of us?
Gazzaniga: Human knowledge can’t help itself in the long run. Things slowly, gradually become more clear. As humans continue on their journey they will come to believe certain things about the nature of things and those abstractions will then be reflected in the rules that are set up to allow people to live together. Beliefs have consequences and we will see them reflected in all kinds of ways. Certainly how we come to think and understand human responsibility in the context of modern knowledge of biologic mechanisms will dictate how we choose our laws and our punishments. What could be more important?
''''''''''''''''''''''''''''''''''''''''''''''''''''''''
Fuente... http://www.scientificamerican.com/article.cfm?id=free-will-and-the-brain-michael-gazzaniga-interview
By Gareth Cook | Tuesday, November 15, 2011 | 41
'''''''''''''''''''''''''''''''''''''''''''''''''''
Do we have free will? It is an age-old question which has attracted the attention of philosophers, theologians, lawyers and political theorists. Now it is attracting the attention of neuroscience, explains Michael S. Gazzaniga, director of the SAGE Center for the Study of the Mind at the University of California, Santa Barbara, and author of the new book, “Who’s In Charge: Free Will and the Science of the Brain.” He spoke with Mind Matters editor Gareth Cook.
Cook: Why did you decide to tackle the question of free will?
Gazzaniga: I think the issue is on every thinking person’s mind. I can remember wondering about it 50 years ago when I was a student at Dartmouth. At that time, the issue was raw and simply stated. Physics and chemistry were king and while all of us were too young to shave, we saw the implications. For me, those were back in the days when I went to Church every Sunday, and sometimes on Monday if I had an exam coming up!
Now, after 50 years of studying the brain, listening to philosophers, and most recently being slowly educated about the law, the issue is back on my front burner. The question of whether we are responsible for our actions -- or robots that respond automatically -- has been around a long time but until recently the great scholars who spoke out on the issue didn’t know modern science with its deep knowledge and implications.
Cook: What makes you think that neuroscience can shed any light on what has long been a philosophical question?
Gazzaniga: Philosophers are the best at articulating the nature of a problem before anybody knows anything empirical. The modern philosophers of mind now seize on neuroscience and cognitive science to help illuminate age old questions and to this day are frequently ahead of the pack. Among other skills, they have time to think! The laboratory scientist is consumed with experimental details, analyzing data, and frequently does not have the time to place a scientific finding into a larger landscape. It is a constant tension.
Having said that, philosophers can’t have all the fun. Faced with the nature of biologic mechanisms morning, noon, and night, neuroscientists can’t help but think about such questions as the nature of “freedom of action in a mechanistic universe” as one great neuroscientist put it years ago. At a minimum, neuroscience directs one’s attention to the question of how does action come about.
Cook: Do you think that neuroscience, as a field, needs to tackle these questions? That is, do you consider free will an important scientific question?
Gazzaniga: We all need to understand more about free will, or more wisely put, the nature of action. Neuroscience is one highly relevant discipline to this issue. Whatever your beliefs about free will, everyone feels like they have it, even those who dispute that it exists. What neuroscience has been showing us, however, is that it all works differently than how we feel it must work. For instance, neuroscientific experiments indicate that human decisions for action are made before the individual is consciously aware of them. Instead of this finding answering the age-old question of whether the brain decides before the mind decides, it makes us wonder if that is even the way to think about how the brain works. Research is focused on many aspects of decision making and actions, such as where in the brain decisions to act are formed and executed, how a bunch of interacting neurons becomes a moral agent, and even how one’s beliefs about whether they have free will affect their actions. The list of issues where neuroscience will weigh in is endless.
Cook: Please explain what you mean by the idea of an "emergent mind," and the distinction you draw between this and the brain?
Gazzaniga: Leibnitz raised the question almost 300 years ago with his analogy of the mill. Imagine that you can blow the mill up in size such that all components are magnified and you can walk among them. All you find are individual mechanical components, a wheel here, a spindle there. By looking at the parts of the mill you cannot deduce its function. The physical brain can also be broken into parts and their interactions examined. We now understand neurons and how they fire and a bit about neurotransmitters and so forth. But somehow the mental properties are indivisible and can’t be described in terms of neuronal firings. They need to be understood in another vocabulary.
This is sometimes called the emergent mind. Emergence as a concept in general is widely accepted in physics, chemistry, biology, sociology, you name it. Neuroscientists, however, have a hard time with it because they are suspicious that this concept is sneaking a ghost into the machine. That is not it at all. The motivation for this suggestion is to conceptualize the actual architecture of the layered brain/mind interaction so it can be properly studied. It is lazy to stay locked into one layer of analysis and to dismiss the other.
Cook: How does the mind constrain the brain?
Gazzaniga: No one said this is going to be easy and here is where the going gets tough. Picking up on the last thought the idea: we are dealing with a layered system, and each layer has its own laws and protocols, just like in physics where Newton’s Laws apply to one layer of physics and quantum mechanics to another. Think of hardware-software layers. Hardware is useless without software and software is useless without hardware.
How are we to capture an understanding how the two layers interact? For now, no one really captures that reality and certainly no one has yet captured how mental states interact with the neurons that produce them. Yet we know the top mental layers and the layers beneath it, which produce it, interact. Patients suffering from depression can be aided by talk therapy (top-down). They can also be aided by pharmacological drugs (bottom up). When these two therapies are combined the therapy is even better. That is an example of the mind constraining the brain.
Cook: And how does this idea of the mind and brain interacting bring you to your position on free will?
Gazzaniga: For me, it captures the fact that we are trying to understand a layered system. One becomes cognizant there is a system on top of the personal mind/brain layers which is yet another layer--the social world. It interacts massively with our mental processes and vice versa. In many ways we humans, in achieving our robustness, have uploaded many of our critical needs to the social system around us so that the stuff we invent can survive our own fragile and vulnerable lives.
Cook: You talk about “abandoning” the idea of free will. Can you explain what you mean by this, and how you came to this conclusion?
Gazzaniga: As I see it, this is the way to think about it: If you were a Martian landing on Earth today and were gathering information how humans work, the idea of free will as commonly understood in folk psychology would not come up. The Martian would learn humans had learned about physics and chemistry and causation in the standard sense. They would be astonished to see the amount of information that has accumulated about how cells work, how brains work and would conclude, “OK, they are getting it. Just like cells are complex wonderful machines, so are brains. They work in cool ways even though there is this strong tug on them to think there is some little guy in their head calling the shots. There is not.”
The world is not flat. Before this truth was realized, people use to wonder what happened when you got to the end of the earth-- did you fall off? Once we knew the earth was round, the new perspective, made us see how the old questions were silly. New questions also seem silly many times until a new perspective is accepted. I think we will get over the idea of free will and and accept we are a special kind of machine, one with a moral agency which comes from living in social groups. This perspective will make us ask new kinds of questions.
Cook: Are there particular experiments which you think have shed important light on the question of free will?
Gazzaniga: All of neuroscience in one way or another is shining light on how the brain works. That is the reality of it and it is that knowledge, slowly accumulating that will drive us to think more deeply. One way to get going on this is to try and answer the simple question. Free from what? What does anybody want to be free from? I surely do not want to be free from the laws of nature.
Cook: Do you think this science is going to force philosophers to change how they think about free will? And how about the rest of us?
Gazzaniga: Human knowledge can’t help itself in the long run. Things slowly, gradually become more clear. As humans continue on their journey they will come to believe certain things about the nature of things and those abstractions will then be reflected in the rules that are set up to allow people to live together. Beliefs have consequences and we will see them reflected in all kinds of ways. Certainly how we come to think and understand human responsibility in the context of modern knowledge of biologic mechanisms will dictate how we choose our laws and our punishments. What could be more important?
''''''''''''''''''''''''''''''''''''''''''''''''''''''''
Fuente... http://www.scientificamerican.com/article.cfm?id=free-will-and-the-brain-michael-gazzaniga-interview
Extremófilos estelares
Noviembre 14, 2011: En los años '70, los biólogos se sorprendieron al descubrir una forma de vida que nunca esperaron que existiera. Pequeños microorganismos con un antiguo ADN vivían en los manantiales hirvientes del Parque Nacional Yellowstone. En vez de disolverse en aquellas aguas en ebullición, los microbios se desarrollaban con éxito, iluminando los manantiales con un color brillante.
Los científicos inventaron entonces el término "extremófilo", que significa "amante de las condiciones extremas", para describir a estas criaturas —y entonces comenzó la búsqueda de otras más. Pronto, se encontraron más organismos extremófilos viviendo a gran profundidad en el hielo de la Antártida, en los núcleos de los reactores nucleares y en otros lugares inesperados. La biología no ha sido la misma desde entonces.
¿Podría la astronomía estar a punto de experimentar una transformación similar?
Usando un telescopio de la NASA, llamado GALEX, los investigadores han descubierto un nuevo tipo de extremófilo: las estrellas amantes de las condiciones extremas.
"Hemos estado encontrando estrellas que viven en ambientes galácticos extremos, donde la formación estelar no se supone que suceda", explica Susan Neff, quien es científica del proyecto GALEX en el Centro Goddard para Vuelos Espaciales (Goddard Space Flight Center, en idioma inglés). "Esta es una situación absolutamente sorprendente".
Stellar Extremophiles (splash, 558px)
Esta imagen compuesta (radio + UV) muestra largos brazos, como los de un pulpo, donde se produce la formación de estrellas a gran distancia del disco principal de la galaxia espiral M83. [Más información] [Video].
GALEX, que es la sigla en idioma inglés de "Galaxy Evolution Explorer" ("Explorador de la Evolución Galáctica", en idioma español), es un telescopio espacial destinado a realizar observaciones en la zona ultravioleta del espectro, y tiene una habilidad especial: es super sensible al tipo de rayos UV (ultravioleta) que emiten las estrellas más jóvenes. Esto significa que el observatorio puede detectar estrellas que están naciendo a muy grandes distancias de la Tierra, a más de la mitad de la distancia que existe desde aquí hasta el extremo del universo. El observatorio fue lanzado al espacio en 2003 en una misión para estudiar cómo las galaxias cambian y evolucionan conforme nuevas estrellas se unen en su interior.
GALEX ha cumplido con dicha misión y ha hecho más también.
"En algunas imágenes proporcionadas por el telescopio GALEX, vemos estrellas que están formándose afuera de las galaxias, en lugares donde pensábamos que la densidad del gas sería demasiado baja como para permitir que se produzca el nacimiento de estrellas", dice Don Neil, de Caltech, quien es miembro del equipo GALEX.
Las estrellas nacen cuando las nubes de gas interestelar colapsan y se contraen bajo el tirón de su propia gravedad. Si una nube logra volverse lo suficientemente densa y caliente conforme colapsa, puede darse una fusión nuclear y ¡voilà!, una estrella ha nacido.
Los brazos espirales de la Vía Láctea son la zona denominada "Ricitos de Oro" para este proceso. "Aquí en la Vía Láctea, tenemos suficiente gas. Es un lugar cómodo para que se formen las estrellas", dice Neil.
Pero cuando el GALEX mira hacia otras galaxias espirales más lejanas, ve que se forman estrellas muy afuera del disco espiral gaseoso.
Stellar Extremophiles (signup)
"Quedé anonadado", dijo. "Estas estrellas de verdad están 'viviendo al extremo'".
Las galaxias espirales no son los únicos lugares con extremófilos estelares. El observatorio también ha encontrado estrellas que nacen en:
—galaxias elípticas e irregulares, de las cuales se pensaba que eran pobres en gas (por ejemplo 1, y 2),
—los residuos gaseosos de galaxias en colisión (1, y 2),
—vastas colas "de tipo cometario" que dejan atrás algunas galaxias al moverse a grandes velocidades (1, 2),
—nubes de frío gas primordial, las cuales son pequeñas y apenas lo suficientemente masivas como para sostenerse a sí mismas.
Adiós a la idea de la zona llamada "Ricitos de Oro". De acuerdo con las observaciones llevadas a cabo por el telescopio GALEX, los extremófilos estelares pueblan casi cualquier esquina o rincón del cosmos en donde haya una bocanada de gas que pueda juntarse para dar lugar a un nuevo sol.
"Esto podría estar diciéndonos que hay algo profundamente importante en el proceso de formación de las estrellas", relata Neff. "Podría haber maneras de que se formen estrellas en ambientes extremos que ni siquiera hemos imaginado todavía".
¿Transformarán los extremófilos a la astronomía, tal como lo hicieron con la biología? Es demasiado pronto para saberlo, insisten los investigadores. Pero el telescopio GALEX definitivamente les ha dado algo en qué pensar.
Tomado de NASA
Créditos y Contactos
Autor: Dr. Tony Phillips
Funcionaria Responsable de NASA: Ruth Netting
Editor de Producción: Dr. Tony Phillips
Traducción al Español: Carlos Román Zúñiga
Editora en Español: Angela Atadía de Borghetti
Formato: Carlos Román Zúñiga
Más información (en inglés)
GALEX —Portal
Los científicos inventaron entonces el término "extremófilo", que significa "amante de las condiciones extremas", para describir a estas criaturas —y entonces comenzó la búsqueda de otras más. Pronto, se encontraron más organismos extremófilos viviendo a gran profundidad en el hielo de la Antártida, en los núcleos de los reactores nucleares y en otros lugares inesperados. La biología no ha sido la misma desde entonces.
¿Podría la astronomía estar a punto de experimentar una transformación similar?
Usando un telescopio de la NASA, llamado GALEX, los investigadores han descubierto un nuevo tipo de extremófilo: las estrellas amantes de las condiciones extremas.
"Hemos estado encontrando estrellas que viven en ambientes galácticos extremos, donde la formación estelar no se supone que suceda", explica Susan Neff, quien es científica del proyecto GALEX en el Centro Goddard para Vuelos Espaciales (Goddard Space Flight Center, en idioma inglés). "Esta es una situación absolutamente sorprendente".
Stellar Extremophiles (splash, 558px)
Esta imagen compuesta (radio + UV) muestra largos brazos, como los de un pulpo, donde se produce la formación de estrellas a gran distancia del disco principal de la galaxia espiral M83. [Más información] [Video].
GALEX, que es la sigla en idioma inglés de "Galaxy Evolution Explorer" ("Explorador de la Evolución Galáctica", en idioma español), es un telescopio espacial destinado a realizar observaciones en la zona ultravioleta del espectro, y tiene una habilidad especial: es super sensible al tipo de rayos UV (ultravioleta) que emiten las estrellas más jóvenes. Esto significa que el observatorio puede detectar estrellas que están naciendo a muy grandes distancias de la Tierra, a más de la mitad de la distancia que existe desde aquí hasta el extremo del universo. El observatorio fue lanzado al espacio en 2003 en una misión para estudiar cómo las galaxias cambian y evolucionan conforme nuevas estrellas se unen en su interior.
GALEX ha cumplido con dicha misión y ha hecho más también.
"En algunas imágenes proporcionadas por el telescopio GALEX, vemos estrellas que están formándose afuera de las galaxias, en lugares donde pensábamos que la densidad del gas sería demasiado baja como para permitir que se produzca el nacimiento de estrellas", dice Don Neil, de Caltech, quien es miembro del equipo GALEX.
Las estrellas nacen cuando las nubes de gas interestelar colapsan y se contraen bajo el tirón de su propia gravedad. Si una nube logra volverse lo suficientemente densa y caliente conforme colapsa, puede darse una fusión nuclear y ¡voilà!, una estrella ha nacido.
Los brazos espirales de la Vía Láctea son la zona denominada "Ricitos de Oro" para este proceso. "Aquí en la Vía Láctea, tenemos suficiente gas. Es un lugar cómodo para que se formen las estrellas", dice Neil.
Pero cuando el GALEX mira hacia otras galaxias espirales más lejanas, ve que se forman estrellas muy afuera del disco espiral gaseoso.
Stellar Extremophiles (signup)
"Quedé anonadado", dijo. "Estas estrellas de verdad están 'viviendo al extremo'".
Las galaxias espirales no son los únicos lugares con extremófilos estelares. El observatorio también ha encontrado estrellas que nacen en:
—galaxias elípticas e irregulares, de las cuales se pensaba que eran pobres en gas (por ejemplo 1, y 2),
—los residuos gaseosos de galaxias en colisión (1, y 2),
—vastas colas "de tipo cometario" que dejan atrás algunas galaxias al moverse a grandes velocidades (1, 2),
—nubes de frío gas primordial, las cuales son pequeñas y apenas lo suficientemente masivas como para sostenerse a sí mismas.
Adiós a la idea de la zona llamada "Ricitos de Oro". De acuerdo con las observaciones llevadas a cabo por el telescopio GALEX, los extremófilos estelares pueblan casi cualquier esquina o rincón del cosmos en donde haya una bocanada de gas que pueda juntarse para dar lugar a un nuevo sol.
"Esto podría estar diciéndonos que hay algo profundamente importante en el proceso de formación de las estrellas", relata Neff. "Podría haber maneras de que se formen estrellas en ambientes extremos que ni siquiera hemos imaginado todavía".
¿Transformarán los extremófilos a la astronomía, tal como lo hicieron con la biología? Es demasiado pronto para saberlo, insisten los investigadores. Pero el telescopio GALEX definitivamente les ha dado algo en qué pensar.
Tomado de NASA
Créditos y Contactos
Autor: Dr. Tony Phillips
Funcionaria Responsable de NASA: Ruth Netting
Editor de Producción: Dr. Tony Phillips
Traducción al Español: Carlos Román Zúñiga
Editora en Español: Angela Atadía de Borghetti
Formato: Carlos Román Zúñiga
Más información (en inglés)
GALEX —Portal
martes, 15 de noviembre de 2011
Planeta gigante expulsado del Sistema Solar ....
ASTRONOMÍA | Formación planetaria
Un planeta gigante expulsado del primitivo Sistema Solar. Se estima su expulsión evitó la destrucción de la Tierra hace 600 millones de años . Se formó en los orígenes del Sistema Solar, hoy con cuatro planetas gigantes
Un equipo de astrónomos acaba de publicar un trabajo que añade la existencia de un quinto planeta gigante al primitivo Sistema Solar. Este astro axplicaría uno de los misterios de nuestro sistema, que se refiere a la formación de las órbitas de los planetas.
Por lo que se conoce, cuando se formó el Sistema Solar, hace unos 4.500 millones de años, hubo un gran inestabilidad en las órbitas de los grandes planetas, hasta el punto que tendrían que haber acabado colisionando con la Tierra primigenia. Su conclusión es que si no ocurrió, se debe a que existía este misterioso cuerpo celeste.
La investigación, publicada en la revista 'Astrophysical Journal', se basa en simulaciones informáticas. Según David Nesvorny, del Southwest Research Institute, sus datos proceden del estudio de los muchos objetos pequeños que hay más allá de Neptuno, en el llamado 'Cinturón de Kuiper', y también del registro de cráteres que hay en la Luna.
De su ánalisis ya se había concluido que cuando el Sistema Solar tenía sólo unos 600 millones de años, había una gran inestabilidad en las órbitas de los planetas gigantes, de los que ahora hay cuatro: Júpiter, Saturno, Neptuno y Urano. Debido a ello, infinidad de cuerpos pequeños se dispersaron (algunos de conforman el Cinturón de Kuiper), pero otros se acercaron hacia el Sol, afectando a la Tierra y la Luna.
Y lo mismo pasó con los grandes. Júpiter, por ejemplo, se habría movido hacia dentro del Sistema lentamente. El problema es que ese movimiento habría afectado a las órbitas de los planetas rocosos como la Tierra, que habría colisionado con sus vecinos, Marte o Venus.
Los astrónomos, en trabajos previos, presentaron una alternativa que evitaba esta opción: propusieron que la órbita de Júpiter cambió con rapidez cuando se dispersó, alejandose de Urano o de Neptuno, durante ese periodo de inestabilidad. Este 'salto' de Júpiter habría sido menos dañino para el resto de los planetas pero, ¿qué lo causó?
Nesvorny realizó millones de simulaciones informáticas para encontrar la respuesta. Si efectivamente Júpiter saltó dispersando a sus dos vecinos gigantes, uno de los dos tendría que haber sido expulsado del Sistema Solar, algo que tampoco ocurrió. "Había algo claramente incorrecto", afirma el investigador.
La única alternativa que se le ocurrió era que había habido un quinto planeta gigante en nuestro entorno cósmico. Y Nesvorny acertó: comprobó que, con esa simulación, todo volvía a su lugar. Ese astro debía haber sido expulsado del Sistema Solar en sus inicios. "Es una explicación que parece bastante concebible debido al descubrimiento reciente de una gran cantidad de planetas que flotan libremente en el espacio ineterestelar, sin orbitar ninguna estrella, lo que indica que estas eyecciones de planetas podían ser comunes", afirma Nesvorny.
Autor: Rosa M. Tristán | Madrid , Actualizado lunes 14/11/2011 16:46 horas
Tomado de : El Pais, España.
Un planeta gigante expulsado del primitivo Sistema Solar. Se estima su expulsión evitó la destrucción de la Tierra hace 600 millones de años . Se formó en los orígenes del Sistema Solar, hoy con cuatro planetas gigantes
Un equipo de astrónomos acaba de publicar un trabajo que añade la existencia de un quinto planeta gigante al primitivo Sistema Solar. Este astro axplicaría uno de los misterios de nuestro sistema, que se refiere a la formación de las órbitas de los planetas.
Por lo que se conoce, cuando se formó el Sistema Solar, hace unos 4.500 millones de años, hubo un gran inestabilidad en las órbitas de los grandes planetas, hasta el punto que tendrían que haber acabado colisionando con la Tierra primigenia. Su conclusión es que si no ocurrió, se debe a que existía este misterioso cuerpo celeste.
La investigación, publicada en la revista 'Astrophysical Journal', se basa en simulaciones informáticas. Según David Nesvorny, del Southwest Research Institute, sus datos proceden del estudio de los muchos objetos pequeños que hay más allá de Neptuno, en el llamado 'Cinturón de Kuiper', y también del registro de cráteres que hay en la Luna.
De su ánalisis ya se había concluido que cuando el Sistema Solar tenía sólo unos 600 millones de años, había una gran inestabilidad en las órbitas de los planetas gigantes, de los que ahora hay cuatro: Júpiter, Saturno, Neptuno y Urano. Debido a ello, infinidad de cuerpos pequeños se dispersaron (algunos de conforman el Cinturón de Kuiper), pero otros se acercaron hacia el Sol, afectando a la Tierra y la Luna.
Y lo mismo pasó con los grandes. Júpiter, por ejemplo, se habría movido hacia dentro del Sistema lentamente. El problema es que ese movimiento habría afectado a las órbitas de los planetas rocosos como la Tierra, que habría colisionado con sus vecinos, Marte o Venus.
Los astrónomos, en trabajos previos, presentaron una alternativa que evitaba esta opción: propusieron que la órbita de Júpiter cambió con rapidez cuando se dispersó, alejandose de Urano o de Neptuno, durante ese periodo de inestabilidad. Este 'salto' de Júpiter habría sido menos dañino para el resto de los planetas pero, ¿qué lo causó?
Nesvorny realizó millones de simulaciones informáticas para encontrar la respuesta. Si efectivamente Júpiter saltó dispersando a sus dos vecinos gigantes, uno de los dos tendría que haber sido expulsado del Sistema Solar, algo que tampoco ocurrió. "Había algo claramente incorrecto", afirma el investigador.
La única alternativa que se le ocurrió era que había habido un quinto planeta gigante en nuestro entorno cósmico. Y Nesvorny acertó: comprobó que, con esa simulación, todo volvía a su lugar. Ese astro debía haber sido expulsado del Sistema Solar en sus inicios. "Es una explicación que parece bastante concebible debido al descubrimiento reciente de una gran cantidad de planetas que flotan libremente en el espacio ineterestelar, sin orbitar ninguna estrella, lo que indica que estas eyecciones de planetas podían ser comunes", afirma Nesvorny.
Autor: Rosa M. Tristán | Madrid , Actualizado lunes 14/11/2011 16:46 horas
Tomado de : El Pais, España.
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