The illusion of now

diumenge, 16/06/2019

Hinze Hogendoorn is an assistant professor at the department of Experimental Psychology (Faculty of Social Sciences) at Utrecht University. His research interests lie in the temporal aspects of perception, particularly vision.

The arrow of time: Sean Carroll

dissabte, 15/06/2019


Transcript Translated by Francisco Gnecco
Reviewed by Sebastian Betti
The universe is really big. We live in a galaxy, the Milky Way Galaxy. There are about a hundred billion stars in the Milky Way Galaxy. And if you take a camera and you point it at a random part of the sky, and you just keep the shutter open, as long as your camera is attached to the Hubble Space Telescope, it will see something like this. Every one of these little blobs is a galaxy roughly the size of our Milky Way — a hundred billion stars in each of those blobs. There are approximately a hundred billion galaxies in the observable universe. 100 billion is the only number you need to know. The age of the universe, between now and the Big Bang, is a hundred billion in dog years. (Laughter) Which tells you something about our place in the universe. 


One thing you can do with a picture like this is simply admire it. It’s extremely beautiful. I’ve often wondered, what is the evolutionary pressure that made our ancestors in the Veldt adapt and evolve to really enjoy pictures of galaxies when they didn’t have any. But we would also like to understand it. As a cosmologist, I want to ask, why is the universe like this? One big clue we have is that the universe is changing with time. If you looked at one of these galaxies and measured its velocity, it would be moving away from you. And if you look at a galaxy even farther away, it would be moving away faster. So we say the universe is expanding.


What that means, of course, is that, in the past, things were closer together. In the past, the universe was more dense, and it was also hotter. If you squeeze things together, the temperature goes up. That kind of makes sense to us. The thing that doesn’t make sense to us as much is that the universe, at early times, near the Big Bang, was also very, very smooth. You might think that that’s not a surprise. The air in this room is very smooth. You might say, “Well, maybe things just smoothed themselves out.” But the conditions near the Big Bang are very, very different than the conditions of the air in this room. In particular, things were a lot denser. The gravitational pull of things was a lot stronger near the Big Bang.


What you have to think about is we have a universe with a hundred billion galaxies, a hundred billion stars each. At early times, those hundred billion galaxies were squeezed into a region about this big — literally — at early times. And you have to imagine doing that squeezing without any imperfections, without any little spots where there were a few more atoms than somewhere else. Because if there had been, they would have collapsed under the gravitational pull into a huge black hole. Keeping the universe very, very smooth at early times is not easy; it’s a delicate arrangement. It’s a clue that the early universe is not chosen randomly. There is something that made it that way. We would like to know what.



So part of our understanding of this was given to us by Ludwig Boltzmann, an Austrian physicist in the 19th century. And Boltzmann’s contribution was that he helped us understand entropy. You’ve heard of entropy. It’s the randomness, the disorder, the chaoticness of some systems. Boltzmann gave us a formula — engraved on his tombstone now — that really quantifies what entropy is. And it’s basically just saying that entropy is the number of ways we can rearrange the constituents of a system so that you don’t notice, so that macroscopically it looks the same. If you have the air in this room, you don’t notice each individual atom. A low entropy configuration is one in which there’s only a few arrangements that look that way. A high entropy arrangement is one that there are many arrangements that look that way. This is a crucially important insight because it helps us explain the second law of thermodynamics — the law that says that entropy increases in the universe, or in some isolated bit of the universe.


The reason why entropy increases is simply because there are many more ways to be high entropy than to be low entropy. That’s a wonderful insight, but it leaves something out. This insight that entropy increases, by the way, is what’s behind what we call the arrow of time, the difference between the past and the future. Every difference that there is between the past and the future is because entropy is increasing — the fact that you can remember the past, but not the future. The fact that you are born, and then you live, and then you die, always in that order, that’s because entropy is increasing. Boltzmann explained that if you start with low entropy, it’s very natural for it to increase because there’s more ways to be high entropy. What he didn’t explain was why the entropy was ever low in the first place.


The fact that the entropy of the universe was low was a reflection of the fact that the early universe was very, very smooth. We’d like to understand that. That’s our job as cosmologists. Unfortunately, it’s actually not a problem that we’ve been giving enough attention to. It’s not one of the first things people would say, if you asked a modern cosmologist, “What are the problems we’re trying to address?” One of the people who did understand that this was a problem was Richard Feynman. 50 years ago, he gave a series of a bunch of different lectures. He gave the popular lectures that became “The Character of Physical Law.” He gave lectures to Caltech undergrads that became “The Feynman Lectures on Physics.” He gave lectures to Caltech graduate students that became “The Feynman Lectures on Gravitation.” In every one of these books, every one of these sets of lectures, he emphasized this puzzle: Why did the early universe have such a small entropy?


So he says — I’m not going to do the accent — he says, “For some reason, the universe, at one time, had a very low entropy for its energy content, and since then the entropy has increased. The arrow of time cannot be completely understood until the mystery of the beginnings of the history of the universe are reduced still further from speculation to understanding.” So that’s our job. We want to know — this is 50 years ago, “Surely,” you’re thinking, “we’ve figured it out by now.” It’s not true that we’ve figured it out by now.


The reason the problem has gotten worse, rather than better, is because in 1998 we learned something crucial about the universe that we didn’t know before. We learned that it’s accelerating. The universe is not only expanding. If you look at the galaxy, it’s moving away. If you come back a billion years later and look at it again, it will be moving away faster. Individual galaxies are speeding away from us faster and faster so we say the universe is accelerating. Unlike the low entropy of the early universe, even though we don’t know the answer for this, we at least have a good theory that can explain it, if that theory is right, and that’s the theory of dark energy. It’s just the idea that empty space itself has energy.


In every little cubic centimeter of space, whether or not there’s stuff, whether or not there’s particles, matter, radiation or whatever, there’s still energy, even in the space itself. And this energy, according to Einstein, exerts a push on the universe. It is a perpetual impulse that pushes galaxies apart from each other. Because dark energy, unlike matter or radiation, does not dilute away as the universe expands. The amount of energy in each cubic centimeter remains the same, even as the universe gets bigger and bigger. This has crucial implications for what the universe is going to do in the future. For one thing, the universe will expand forever.



Back when I was your age, we didn’t know what the universe was going to do. Some people thought that the universe would recollapse in the future. Einstein was fond of this idea. But if there’s dark energy, and the dark energy does not go away, the universe is just going to keep expanding forever and ever and ever. 14 billion years in the past, 100 billion dog years, but an infinite number of years into the future. Meanwhile, for all intents and purposes, space looks finite to us. Space may be finite or infinite, but because the universe is accelerating, there are parts of it we cannot see and never will see. There’s a finite region of space that we have access to, surrounded by a horizon. So even though time goes on forever, space is limited to us. Finally, empty space has a temperature.


In the 1970s, Stephen Hawking told us that a black hole, even though you think it’s black, it actually emits radiation when you take into account quantum mechanics. The curvature of space-time around the black hole brings to life the quantum mechanical fluctuation, and the black hole radiates. A precisely similar calculation by Hawking and Gary Gibbons showed that if you have dark energy in empty space, then the whole universe radiates. The energy of empty space brings to life quantum fluctuations. And so even though the universe will last forever, and ordinary matter and radiation will dilute away, there will always be some radiation, some thermal fluctuations, even in empty space. So what this means is that the universe is like a box of gas that lasts forever. Well what is the implication of that?


That implication was studied by Boltzmann back in the 19th century. He said, well, entropy increases because there are many, many more ways for the universe to be high entropy, rather than low entropy. But that’s a probabilistic statement. It will probably increase, and the probability is enormously huge. It’s not something you have to worry about — the air in this room all gathering over one part of the room and suffocating us. It’s very, very unlikely. Except if they locked the doors and kept us here literally forever, that would happen. Everything that is allowed, every configuration that is allowed to be obtained by the molecules in this room, would eventually be obtained.


So Boltzmann says, look, you could start with a universe that was in thermal equilibrium. He didn’t know about the Big Bang. He didn’t know about the expansion of the universe. He thought that space and time were explained by Isaac Newton — they were absolute; they just stuck there forever. So his idea of a natural universe was one in which the air molecules were just spread out evenly everywhere — the everything molecules. But if you’re Boltzmann, you know that if you wait long enough, the random fluctuations of those molecules will occasionally bring them into lower entropy configurations. And then, of course, in the natural course of things, they will expand back. So it’s not that entropy must always increase — you can get fluctuations into lower entropy, more organized situations.


Well if that’s true, Boltzmann then goes onto invent two very modern-sounding ideas — the multiverse and the anthropic principle. He says, the problem with thermal equilibrium is that we can’t live there. Remember, life itself depends on the arrow of time. We would not be able to process information, metabolize, walk and talk, if we lived in thermal equilibrium. So if you imagine a very, very big universe, an infinitely big universe, with randomly bumping into each other particles, there will occasionally be small fluctuations in the lower entropy states, and then they relax back. But there will also be large fluctuations. Occasionally, you will make a planet or a star or a galaxy or a hundred billion galaxies. So Boltzmann says, we will only live in the part of the multiverse, in the part of this infinitely big set of fluctuating particles, where life is possible. That’s the region where entropy is low. Maybe our universe is just one of those things that happens from time to time.


Now your homework assignment is to really think about this, to contemplate what it means. Carl Sagan once famously said that “in order to make an apple pie, you must first invent the universe.” But he was not right. In Boltzmann’s scenario, if you want to make an apple pie, you just wait for the random motion of atoms to make you an apple pie. That will happen much more frequently than the random motions of atoms making you an apple orchard and some sugar and an oven, and then making you an apple pie. So this scenario makes predictions. And the predictions are that the fluctuations that make us are minimal. Even if you imagine that this room we are in now exists and is real and here we are, and we have, not only our memories, but our impression that outside there’s something called Caltech and the United States and the Milky Way Galaxy, it’s much easier for all those impressions to randomly fluctuate into your brain than for them actually to randomly fluctuate into Caltech, the United States and the galaxy.



The good news is that, therefore, this scenario does not work; it is not right. This scenario predicts that we should be a minimal fluctuation. Even if you left our galaxy out, you would not get a hundred billion other galaxies. And Feynman also understood this. Feynman says, “From the hypothesis that the world is a fluctuation, all the predictions are that if we look at a part of the world we’ve never seen before, we will find it mixed up, and not like the piece we’ve just looked at — high entropy. If our order were due to a fluctuation, we would not expect order anywhere but where we have just noticed it. We therefore conclude the universe is not a fluctuation.” So that’s good. The question is then what is the right answer? If the universe is not a fluctuation, why did the early universe have a low entropy? And I would love to tell you the answer, but I’m running out of time.




Here is the universe that we tell you about, versus the universe that really exists. I just showed you this picture. The universe is expanding for the last 10 billion years or so. It’s cooling off. But we now know enough about the future of the universe to say a lot more. If the dark energy remains around, the stars around us will use up their nuclear fuel, they will stop burning. They will fall into black holes. We will live in a universe with nothing in it but black holes. That universe will last 10 to the 100 years — a lot longer than our little universe has lived. The future is much longer than the past. But even black holes don’t last forever. They will evaporate, and we will be left with nothing but empty space. That empty space lasts essentially forever. However, you notice, since empty space gives off radiation, there’s actually thermal fluctuations, and it cycles around all the different possible combinations of the degrees of freedom that exist in empty space. So even though the universe lasts forever, there’s only a finite number of things that can possibly happen in the universe. They all happen over a period of time equal to 10 to the 10 to the 120 years.


So here’s two questions for you. Number one: If the universe lasts for 10 to the 10 to the 120 years, why are we born in the first 14 billion years of it, in the warm, comfortable afterglow of the Big Bang? Why aren’t we in empty space? You might say, “Well there’s nothing there to be living,” but that’s not right. You could be a random fluctuation out of the nothingness. Why aren’t you? More homework assignment for you.



So like I said, I don’t actually know the answer. I’m going to give you my favorite scenario. Either it’s just like that. There is no explanation. This is a brute fact about the universe that you should learn to accept and stop asking questions. Or maybe the Big Bang is not the beginning of the universe. An egg, an unbroken egg, is a low entropy configuration, and yet, when we open our refrigerator, we do not go, “Hah, how surprising to find this low entropy configuration in our refrigerator.” That’s because an egg is not a closed system; it comes out of a chicken. Maybe the universe comes out of a universal chicken. Maybe there is something that naturally, through the growth of the laws of physics, gives rise to universe like ours in low entropy configurations. If that’s true, it would happen more than once; we would be part of a much bigger multiverse. That’s my favorite scenario.


So the organizers asked me to end with a bold speculation. My bold speculation is that I will be absolutely vindicated by history. And 50 years from now, all of my current wild ideas will be accepted as truths by the scientific and external communities. We will all believe that our little universe is just a small part of a much larger multiverse. And even better, we will understand what happened at the Big Bang in terms of a theory that we will be able to compare to observations. This is a prediction. I might be wrong. But we’ve been thinking as a human race about what the universe was like, why it came to be in the way it did for many, many years. It’s exciting to think we may finally know the answer someday.

Thank you.


El Universo es realmente grande. Vivimos en una galaxia, la Vía Láctea. Hay unas cien mil millones de estrellas en la Vía Láctea. Y si toman sus cámaras y las enfocan hacia cualquier parte del firmamento y dejan el obturador abierto, siempre que la cámara esté atada al Telescopio espacial Hubble, se verá algo como esto. Cada una de estas pequeñas gotas es una galaxia aproximadamente del mismo tamaño de la Vía Láctea; cien mil millones de estrellas en cada una de esas gotas. Hay unas cien mil millones de galaxias en el Universo observable. Cien mil millones es el único número que hay que saber. La edad del Universo, desde el Big Bang hasta ahora, es como cien mil millones de años caninos. (Risas) Esto nos dice algo sobre nuestro lugar en el Universo. 


Algo que podemos hacer con una foto como ésta, es simplemente admirarla. Es en extremo hermo-sa. A menudo me pregunto, ¿cuál sería la presión evolutiva que hizo que nuestros antepasados en las praderas africanas se adaptaran y evolucio-naran hasta llegar a disfrutar las fotos de las galaxias cuando aún no tenían ninguna? Nos encantaría entenderlo. Como cosmólogo, quisiera preguntar ¿por qué el Universo es como es? Un gran indicio que tenemos es que con el tiempo, el Universo ha ido cambiando. Si miramos una de estas galaxias y medimos su velocidad, vemos que se aleja de nosotros. Y si miramos otra galaxia más lejana aún, se ve moverse más rápido. Así, decimos que el Universo está un expansión.


Esto quiere decir, desde luego, que en el pasado, las cosas estaban más cerca. En el pasado, el Universo era más denso y también más caliente. Si las cosas se comprimen, se eleva la temperatu-ra. Eso tiene sentido. Lo que no parece tener tanto sentido es que el Universo, en su inicio, cerca al Big Bang, era también muy, muy homogéneo. Podría pensarse que esto no es sorpresivo. El aire en esta sala es bien homogéneo. Podría decirse, “bueno, quizá las cosas se homogeneizaron solas”. Pero las condiciones cercanas al Big Bang eran muy, muy diferentes de las del aire de esta sala. En especial, todo era mucho más denso. La fuerza de la gravedad era mucho más fuerte cerca al Big Bang.


Lo que hay que pensar es que tenemos un Universo con cien mil millones de galaxias, de cien mil millones de estrellas cada una. En el principio esas cien mil millones de galaxias estaban concentradas en una región de este tamaño, literalmente, en los tiempos iniciales. Imagínense Uds produciendo esa compactación, sin imperfecciones, sin ningún punto con unos pocos átomos de más que en otros lugares. Porque si lo hubiera habido, habría colapsado por la fuerza gravitatoria para volverse un enorme agujero negro. Conservar el Universo bien homogéneo en etapas tempranas, no es fácil; es un arreglo delicado. Es un indicio de que el Universo primitivo no se elige al azar. Hay algo que lo hizo así. Quisiéramos saber qué fue.


En parte lo que sabemos sobre esto se lo debemos a Ludwig Boltzmann, un físico austríaco del siglo XIX. Boltzmann ayudó a entender la entropía. Habrán oído de la entropía. Es la aleatoridad, el desorden, el caos de un sistema. Boltzmann nos dio una fórmula, ahora grabada en su tumba, que cuantifica la entropía. Básicamente, es como decir que la entropía es la cantidad de formas en que pueden organizarse las partes de un sistema, sin que se note, o sea, que macroscópicamente se vea igual. En el aire de este salón, no se nota cada átomo en forma individual. Una configuración de baja entropía es aquella que tiene pocas maneras de lograrlo. Una configuración de alta entropía es aquella en la que hay muchas maneras de hacer-lo. Esta es una idea muy importante, porque nos ayuda a entender la segunda ley de la termodi-námica; la que dice que la entropía aumenta en el Universo o en partes aisladas del Universo.



La razón por la que aumenta la entropía es simplemente porque hay muchas más formas de tener alta entropía, que de tenerla baja. Una idea estupenda. pero deja algo por fuera. A propósito, esta idea de que la entropía crece, es el funda-mento de lo que llamamos la flecha del tiempo, la diferencia entre el pasado y el futuro. Todas las diferencias que hay entre el pasado y el futuro se deben al aumento de la entropía; lo cual hace que podamos recordar el pasado, pero no el futuro. Que nacemos, luego vivimos y después morimos, siempre en ese orden, se debe a que la entropía va en aumento. Boltzmann explicaba que si se empieza con baja entropía, es muy natural que ésta aumente, porque hay más maneras de tener alta entropía. Lo que él nunca dijo es, por qué la entropía era tan baja al principio.


Que la entropía del Universo fuese baja es otra manera de decir que el Universo era muy, muy homogéneo. Nos gustaría entender esto. Esa es nuestra tarea como cosmólogos. Desafortunadamente, este no es un problema al que le hayamos dedicado suficiente atención. No es una de las primeras respuestas que contestaría un cosmólogo moderno, a la pregunta: “¿Cuáles son los problemas que están abordando?” Uno de los que sí entendió que ahí había un problema fue Richard Feynman. Hace 50 años que dio unas cuantas conferencias. Dictó las conocidas charlas denominadas “El carácter de la ley física”. Dio clases a los estudiantes de pregrado de Caltech que luego se llamaron “Clases de física de Feynman”. Dictó clases a los estudiantes gra-duados de Caltech que se volvieron “Clases de gravitación de Feynman”. En todos sus libros, en todas esas series, él hacía hincapié en el enigma: ¿por qué el Universo temprano tenía tan baja entropía?


El decía (no voy a imitar su acento) “Por alguna razón el Universo en ese tiempo, tenía baja entropía para su contenido de energía y desde entonces la entropía ha venido creciendo. No es posible entender completamente la flecha del tiempo sin antes descubrir el misterio del co-mienzo del Universo, avanzando de la especu-lación a la comprensión”. Y ese es nuestro tra-bajo. Queremos conocerlo –esto fue hace 50 años, “Sí, claro”, pensarán Uds. “pensábamos que estaba resuelto” Pero no es cierto que ya esté resuelto.


La razón por la que el problema se ha compli-cado, en lugar de mejorarse, es porque en 1998 se descubrió algo crucial sobre el Universo, que antes no se sabía. Se supo que está acelerándose. El Universo no sólo se está expandiendo. Si miramos una galaxia, se está alejando. Y si volvemos a mirar mil millones de años después, la veremos moverse más rápido. Las galaxias, individualmente, se aceleran alejándose cada vez más rápido. Por eso decimos que el Universo se está acelerando. A diferencia de la baja entropía del Universo temprano, aunque no sabemos la respuesta, al menos tenemos una buena teoría para explicarlo, esperemos sea la correcta, es la teoría de la energía oscura. Es la idea que dice que el espacio vacío tiene energía.



En cada pequeño centímetro cúbico de espacio, haya o no algo ahí, haya o no partículas, materia, radiación o lo que sea, de todas formas hay energía en el espacio mismo. Y, según Einstein, esta energía ejerce presión sobre el Universo. Un impulso perpetuo que hace alejar las galaxias, unas de otras. Porque la energía oscura, a diferencia de la materia o la radiación, no se diluye con la expansión del Universo. La cantidad de energía en cada centímetro cúbico permanece igual, aunque el Universo se haga cada vez más grande. Esto tiene unas implicaciones cruciales en el futuro del Universo. En primer lugar, el Universo siempre continuará expandiéndose.


Cuando yo tenía la edad de ustedes, no sabíamos lo que iba a pasar con el Universo. Algunos pensaban que en el futuro volvería a colapsar. Einstein creía eso. Pero si existe la energía oscura y ésta no desaparece, el Universo continuará expandiéndose eternamente. 14 mil millones de años en el pasado, 100 mil millones de años caninos, una cantidad infinita de años hacia el futuro. Entre tanto, desde todo punto de vista, vemos el espacio como finito. Puede ser finito o infinito, pero como el Universo se está acelerando, hay partes que no podemos ver y nunca veremos. Hay una región finita del espacio a la cual podemos acceder, limitada por un horizonte. Así, aunque el tiempo continúe para siempre, el espacio, para nosotros, es limitado. Finalmente, el espacio vacío tiene una temperatura.


En la década del 70, Stephen Hawking dijo que un agujero negro, aunque se crea que es negro, en realidad emite radiación, de acuerdo con la mecánica cuántica. La curvatura del espacio-tiempo cerca de un agujero negro hace realidad las fluctuaciones mecánico-cuánticas, y el agujero negro emite radiación. Unos cálculos similares, muy precisos, de Hawking y Gary Gibbons, demostraron que si se tiene energía oscura en el espacio vacío, el Universo entero emite radiación. La energía del espacio vacío hace realidad las fluctuaciones cuánticas. Y aunque el Universo dure eternamente y la materia común y la radiación se diluyan, siempre habrá algo de radiación, algunas fluctuaciones térmicas, aún en el espacio vacío. Lo que quiero decir es que el Universo es como una caja llena de gas que durará eternamente. ¿Y eso qué consecuencia tiene?


Boltzmann estudió la consecuencia en el siglo XIX. Él dijo que la entropía aumenta porque hay muchas más formas que el Universo tenga alta entropía, a que la tenga baja. Pero esta es una afirmación probabilística. Se espera que siga aumentando con una probabilidad enormemente grande. No hay por qué preocuparse porque el aire en esta sala se concentre en una pequeña parte y nos asfixiemos. Es muy, muy poco probable. Salvo que cerraran las puertas y nos mantuvieran aquí, literalmente para siempre, así sí podría suceder. Todo lo que es permitido, toda configuración permitida para las moléculas en este salón, eventualmente podría ocurrir.



Boltzmann dice que podríamos comenzar con un Universo en equilibrio térmico. Él no sabía nada del Big Bang, ni de la expansión del Universo. Él pensaba que el espacio y el tiempo, como lo explicó Isaac Newton, eran absolutos y que así continuarían eternamente. Su idea de un Universo natural era tal que las moléculas de aire se esparcían uniformemente por todas partes, moléculas de todo. Pero si usted fuera Boltzmann, sabría que si espera lo suficiente, las fluctuaciones aleatorias de esas moléculas eventualmente las llevarán a configuraciones de entropía menor. Y entonces, en el curso natural de las cosas, se expandirán nuevamente. O sea, no es que la entropía siempre aumente; pueden tenerse fluctuaciones de menor entropía, situaciones más organizadas.


Y si esto es cierto, Boltzmann habría inventado dos ideas que hoy suenan muy modernas; el multiverso y el principio antrópico. Él decía que el problema del equilibrio térmico es que no podemos vivir en él. Recuerden que la vida misma depende de la flecha del tiempo. No podríamos procesar información, metabolizar, caminar o hablar si viviéramos en equilibrio térmico. Imagínense ahora un Universo muy, muy grande, infinitamente grande, con partículas que se chocan al azar; ocasionalmente habrá pequeñas fluctuaciones con estados de baja entropía para luego volver al estado de distensión. Pero también habrá grandes fluctuaciones. Ocasionalmente surgirá un planeta o una estrella, o una galaxia, o cien mil millones de galaxias. Y Boltzmann dice que solamente viviremos en esta parte del multiverso, en esta parte del conjunto infinitamente grande de partículas que fluctúan, donde es posible la vida. Esa es la región de baja entropía. Puede que nuestro Universo sea una de esas cosas que suceden cada tanto.


Ahora viene la tarea para Uds.; hay que pensar en esto, pensar qué significa. Carl Sagan dijo una vez: “para hacer un pastel de manzana, primero hay que inventar el Universo”. Pero no es correcto. En el escenario de Boltzmann, si quieres hacer un pastel de manzana, sólo hay que esperar a que los movimientos aleatorios de los átomos te hagan el pastel. Eso sucederá con frecuencia mucho mayor a que los movimientos aleatorios de los átomos generen una huerta de manzanos azúcar, un horno y luego hagan el pastel de manzana. Este escenario hace predicciones. Y esas predicciones dicen que las fluctuaciones que nos generan a nosotros, son mínimas. Imagínense que este salón en el que estamos hoy existe y es real y aquí estamos, y no sólo tenemos recuerdos sino también la impresión de que allá afuera hay algo llamado Caltech y los Estados Unidos y la Vía Láctea. Es más fácil que estas impresiones fluctúen aleatoriamente en sus cerebros a que las cosas, en la realidad, fluctúen y existan Caltech y los Estados Unidos y la galaxia.


La buena noticia es que, como consecuencia, ese escenario no se da; no es correcto. El escenario predice que somos una mínima fluctuación. Aunque dejáramos por fuera nuestra galaxia, no llegaríamos a tener cien mil millones de otras galaxias. Y Feynman también entendía esto. Él dijo: “Por la hipótesis de que el mundo es una fluctuación, las predicciones dicen que si miramos una parte del mundo que nunca antes habíamos visto, la encontraremos toda revuelta, más que cualquiera que vimos antes; con mayor entropía. Si nuestro orden se debe a una fluctuación, no podemos esperar orden en todas partes, sólo en donde lo acabamos de encontrar. Por consiguiente, concluimos que el Universo no es una fluctuación”. Eso está bien. La pregunta es entonces: ¿Cuál será la respuesta? Si el Universo no es una fluctuación, ¿por qué razón el Universo temprano tiene baja entropía? Me encantaría poder darles la respuesta, pero se me está acabando el tiempo.



Aquí está el Universo del que hablábamos, frente al que existe en realidad. Ya les había mostrado esta gráfica. El Universo se viene expandiendo desde hace unos 10 mil millones de años. Se viene enfriando. Pero ahora sabemos lo suficiente sobre el futuro del Universo, dicho ambiciosamente. Si la energía oscura permanece a nuestro alrededor, las estrellas que nos rodean usarán todo su combustible nuclear y dejarán de alumbrar. Se reducirán a agujeros negros. Viviremos en un Universo sin nada, sólo agujeros negros. Ese Universo habrá de durar 10 elevado a la 100 años; mucho más de lo que ha vivido hasta ahora. El futuro es mucho más largo que el pasado. Pero aún los agujeros negros no duran para siempre. Se evaporan y quedaremos sin nada, sólo espacio vacío. Ese espacio vacío, esencialmente ha de durar eternamente. Sin embargo, fíjense que como ese espacio vacío emite radiación, habrá fluctuaciones térmicas y se reciclarán las distintas combinaciones posibles de los grados de libertad que existan en el espacio vacío. Así que aunque el Universo ha de durar para siempre, sólo habrá un número finito de cosas que pueden suceder en él. Y todas ellas han de suceder en un período de tiempo igual a 10 elevado a la 10, elevado a la 120, años.


Y ahora hay dos preguntas para ustedes. La primera: Si el Universo durará 10 elevado a la 10, elevado a la 120, años, ¿por qué razón nacimos en los primeros 14 mil millones de años, pasado el Big Bang, en un momento cálido y confortable, ¿Por qué no estamos en el espacio vacío? Dirán ustedes, “es que no hay nada ahí para vivir”. Pero eso no es correcto. Podríamos ser una fluctuación aleatoria de esa nada. ¿Por qué no lo somos? Otra tarea para el hogar.


Cómo ya dije: no sé la respuesta. Pero voy a darles mi escenario favorito. Puede que así sea. Pero no hay explicación. Son datos fríos sobre el Universo que toca aceptar sin hacer preguntas. Puede ser que el Big Bang no sea el principio del Universo. Un huevo sin abrir es una configura-ción de baja entropía y aún así, al abrir el refrigerador no decimos, “¡Ajá!, qué sorpresa encontrar esta configuración de baja entropía en mi refrigerador”. Esto es porque el huevo no es un sistema cerrado; viene de una gallina. Es posible que el Universo venga de una gallina universal. Puede ser que exista algo que, de manera natural, según el desarrollo de las leyes de la física, le dé origen a un Universo como el nuestro, con una configuración de baja entropía. Si es así, esto habría de suceder más de una vez; seríamos parte de un multiverso mucho más grande. Este es mi escenario favorito.


Pero los organizadores me pidieron que terminara con una especulación atrevida. Mi especulación audaz es que la historia me dará la razón totalmente. Y dentro de 50 años, todas mis ideas extravagantes serán aceptadas como verdaderas por la comunidad científica y por todo el mundo. Todos aceptaremos que nuestro pequeño Universo es sólo una pequeña parte de un multiverso mucho mayor. Y aún mejor, entenderemos lo que sucedió en el Big Bang en función de una teoría que podremos comparar con observaciones. Esta es mi predicción. Puedo estar equivocado. Pero la especie humana ha venido pensando por muchos, muchos años, sobre cómo es el Universo y por qué surgió de esta forma. Es emocionante pensar que finalmente podemos conocer la respuesta.



Sightings are increasing

divendres, 14/06/2019

Police UFO Sighting

divendres, 14/06/2019

Sara Seager at TEDx

dijous, 13/06/2019

 TRANSCRIPT Translated by Lidia Cámara de la Fuente

Reviewed by Ciro Gomez
I’m here to tell you about the real search for alien life. Not little green humanoids arriving in shiny UFOs, although that would be nice. But it’s the search for planets orbiting stars far away.
Every star in our sky is a sun. And if our sun has planets — Mercury, Venus, Earth, Mars, etc., surely those other stars should have planets also, and they do. And in the last two decades, astronomers have found thousands of exoplanets.
Our night sky is literally teeming with exoplanets. We know, statistically speaking, that every star has at least one planet. And in the search for planets, and in the future, planets that might be like Earth, we’re able to help address some of the most amazing and mysterious questions that have faced humankind for centuries. Why are we here? Why does our universe exist? How did Earth form and evolve? How and why did life originate and populate our planet? The second question that we often think about is: Are we alone? Is there life out there? Who is out there? You know, this question has been around for thousands of years, since at least the time of the Greek philosophers. But I’m here to tell you just how close we’re getting to finding out the answer to this question. It’s the first time in human history that this really is within reach for us.
Now when I think about the possibilities for life out there, I think of the fact that our sun is but one of many stars. This is a photograph of a real galaxy, we think our Milky Way looks like this galaxy. It’s a collection of bound stars. But our [sun] is one of hundreds of billions of stars and our galaxy is one of upwards of hundreds of billions of galaxies. Knowing that small planets are very common, you can just do the math. And there are just so many stars and so many planets out there, that surely, there must be life somewhere out there. Well, the biologists get furious with me for saying that, because we have absolutely no evidence for life beyond Earth yet.
Well, if we were able to look at our galaxy from the outside and zoom in to where our sun is, we see a real map of the stars. And the highlighted stars are those with known exoplanets. This is really just the tip of the iceberg. Here, this animation is zooming in onto our solar system. And you’ll see here the planets as well as some spacecraft that are also orbiting our sun. Now if we can imagine going to the West Coast of North America, and looking out at the night sky, here’s what we’d see on a spring night. And you can see the constellations overlaid and again, so many stars with planets. There’s a special patch of the sky where we have thousands of planets.
This is where the Kepler Space Telescope focused for many years. Let’s zoom in and look at one of the favorite exoplanets. This star is called Kepler-186f. It’s a system of about five planets. And by the way, most of these exoplanets, we don’t know too much about. We know their size, and their orbit and things like that. But there’s a very special planet here called Kepler-186f. This planet is in a zone that is not too far from the star, so that the temperature may be just right for life. Here, the artist’s conception is just zooming in and showing you what that planet might be like.
So, many people have this romantic notion of astronomers going to the telescope on a lonely mountaintop and looking at the spectacular night sky through a big telescope. But actually, we just work on our computers like everyone else, and we get our data by email or downloading from a database. So instead of coming here to tell you about the somewhat tedious nature of the data and data analysis and the complex computer models we make, I have a different way to try to explain to you some of the things that we’re thinking about exoplanets.
Here’s a travel poster: “Kepler-186f: Where the grass is always redder on the other side.” That’s because Kepler-186f orbits a red star, and we’re just speculating that perhaps the plants there, if there is vegetation that does photosynthesis, it has different pigments and looks red. “Enjoy the gravity on HD 40307g, a Super-Earth.” This planet is more massive than Earth and has a higher surface gravity. “Relax on Kepler-16b, where your shadow always has company.”(Laughter)

We know of a dozen planets that orbit two stars, and there’s likely many more out there. If we could visit one of those planets, you literally would see two sunsets and have two shadows. So actually, science fiction got some things right. Tatooine from Star Wars. And I have a couple of other favorite exoplanets to tell you about. This one is Kepler-10b, it’s a hot, hot planet. It orbits over 50 times closer to its star than our Earth does to our sun. And actually, it’s so hot, we can’t visit any of these planets, but if we could, we would melt long before we got there. We think the surface is hot enough to melt rock and has liquid lava lakes.


Gliese 1214b. This planet, we know the mass and the size and it has a fairly low density. It’s somewhat warm. We actually don’t know really anything about this planet, but one possibility is that it’s a water world, like a scaled-up version of one of Jupiter’s icy moons that might be 50 percent water by mass. And in this case, it would have a thick steam atmosphere overlaying an ocean, not of liquid water, but of an exotic form of water, a superfluid — not quite a gas, not quite a liquid. And under that wouldn’t be rock, but a form of high-pressure ice, like ice IX.


So out of all these planets out there and the variety is just simply astonishing, we mostly want to find the planets that are Goldilocks planets, we call them. Not too big, not too small, not too hot, not too cold — but just right for life. But to do that, we’d have to be able to look at the planet’s atmosphere, because the atmosphere acts like a blanket trapping heat — the greenhouse effect. We have to be able to assess the greenhouse gases on other planets. Well, science fiction got some things wrong. The Star Trek Enterprise had to travel vast distances at incredible speeds to orbit other planets so that First Officer Spock could analyze the atmosphere to see if the planet was habitable or if there were life forms there.


Well, we don’t need to travel at warp speeds to see other planet atmospheres, although I don’t want to dissuade any budding engineers from figuring out how to do that. We actually can and do study planet atmospheres from here, from Earth orbit. This is a picture, a photograph of the Hubble Space Telescope taken by the shuttle Atlantis as it was departing after the last human space flight to Hubble. They installed a new camera, actually, that we use for exoplanet atmospheres. And so far, we’ve been able to study dozens of exoplanet atmospheres, about six of them in great detail. But those are not small planets like Earth. They’re big, hot planets that are easy to see. We’re not ready, we don’t have the right technology yet to study small exoplanets. But nevertheless, I wanted to try to explain to you how we study exoplanet atmospheres.


I want you to imagine, for a moment, a rainbow. And if we could look at this rainbow closely, we would see that some dark lines are missing. And here’s our sun, the white light of our sun split up, not by raindrops, but by a spectrograph. And you can see all these dark, vertical lines. Some are very narrow, some are wide, some are shaded at the edges. And this is actually how astronomers have studied objects in the heavens, literally, for over a century. So here, each different atom and molecule has a special set of lines, a fingerprint, if you will. And that’s how we study exoplanet atmospheres. And I’ll just never forget when I started working on exoplanet atmospheres 20 years ago, how many people told me, “This will never happen. We’ll never be able to study them. Why are you bothering?” And that’s why I’m pleased to tell you about all the atmospheres studied now, and this is really a field of its own. So when it comes to other planets, other Earths, in the future when we can observe them, what kind of gases would we be looking for? Well, you know, our own Earth has oxygen in the atmosphere to 20 percent by volume. That’s a lot of oxygen. But without plants and photosynthetic life, there would be no oxygen, virtually no oxygen in our atmosphere. So oxygen is here because of life. And our goal then is to look for gases in other planet atmospheres, gases that don’t belong, that we might be able to attribute to life. But which molecules should we search for? I actually told you how diverse exoplanets are. We expect that to continue in the future when we find other Earths.


And that’s one of the main things I’m working on now, I have a theory about this. It reminds me that nearly every day, I receive an email or emails from someone with a crazy theory about physics of gravity or cosmology or some such. So, please don’t email me one of your crazy theories. (Laughter) Well, I had my own crazy theory. But, who does the MIT professor go to? Well, I emailed a Nobel Laureate in Physiology or Medicine and he said, “Sure, come and talk to me.” So I brought my two biochemistry friends and we went to talk to him about our crazy theory. And that theory was that life produces all small molecules, so many molecules. Like, everything I could think of, but not being a chemist. Think about it: carbon dioxide, carbon monoxide, molecular hydrogen, molecular nitrogen, methane, methyl chloride — so many gases. They also exist for other reasons, but just life even produces ozone. So we go to talk to him about this, and immediately, he shot down the theory. He found an example that didn’t exist. So, we went back to the drawing board and we think we have found something very interesting in another field.


But back to exoplanets, the point is that life produces so many different types of gases, literally thousands of gases. And so what we’re doing now is just trying to figure out on which types of exoplanets, which gases could be attributed to life. And so when it comes time when we find gases in exoplanet atmospheres that we won’t know if they’re being produced by intelligent aliens or by trees, or a swamp, or even just by simple, single-celled microbial life.


So working on the models and thinking about biochemistry, it’s all well and good. But a really big challenge ahead of us is: how? How are we going to find these planets? There are actually many ways to find planets, several different ways. But the one that I’m most focused on is how can we open a gateway so that in the future, we can find hundreds of Earths. We have a real shot at finding signs of life. And actually, I just finished leading a two-year project in this very special phase of a concept we call the starshade. And the starshade is a very specially shaped screen and the goal is to fly that starshade so it blocks out the light of a star so that the telescope can see the planets directly. Here, you can see myself and two team members holding up one small part of the starshade. It’s shaped like a giant flower, and this is one of the prototype petals. The concept is that a starshade and telescope could launch together, with the petals unfurling from the stowed position. The central truss would expand, with the petals snapping into place. Now, this has to be made very precisely, literally, the petals to microns and they have to deploy to millimeters. And this whole structure would have to fly tens of thousands of kilometers away from the telescope. It’s about tens of meters in diameter. And the goal is to block out the starlight to incredible precision so that we’d be able to see the planets directly. And it has to be a very special shape, because of the physics of defraction. Now this is a real project that we worked on, literally, you would not believe how hard. Just so you believe it’s not just in movie format, here’s a real photograph of a second-generation stars hade deployment test bed in the lab. And in this case, I just wanted you to know that that central truss has heritage left over from large radio deployables in space.


So after all of that hard work where we try to think of all the crazy gases that might be out there, and we build the very complicated space telescopes that might be out there, what are we going to find? Well, in the best case, we will find an image of another exo-Earth. Here is Earth as a pale blue dot. And this is actually a real photograph of Earth taken by the Voyager 1 spacecraft, four billion miles away. And that red light is just scattered light in the camera optics.


But what’s so awesome to consider is that if there are intelligent aliens orbiting on a planet around a star near to us and they build complicated space telescopes of the kind that we’re trying to build, all they’ll see is this pale blue dot, a pinprick of light. And so sometimes, when I pause to think about my professional struggle and huge ambition, it’s hard to think about that in contrast to the vastness of the universe. But nonetheless, I am devoting the rest of my life to finding another Earth.


And I can guarantee that in the next generation of space telescopes, in the second generation, we will have the capability to find and identity other Earths. And the capability to split up the starlight so that we can look for gases and assess the greenhouse gases in the atmosphere, estimate the surface temperature, and look for signs of life.


But there’s more. In this case of searching for other planets like Earth, we are making a new kind of map of the nearby stars and of the planets orbiting them, including [planets] that actually might be inhabitable by humans.


And so I envision that our descendants, hundreds of years from now, will embark on an interstellar journey to other worlds. And they will look back at all of us as the generation who first found the Earth-like worlds.
Thank you.
June Cohen: And I give you, for a question, Rosetta Mission Manager Fred Jansen.


Fred Jansen: You mentioned halfway through that the technology to actually look at the spectrum of an exoplanet like Earth is not there yet. When do you expect this will be there, and what’s needed?


Actually, what we expect is what we call our next-generation Hubble telescope. And this is called the James Webb Space Telescope, and that will launch in 2018, and that’s what we’re going to do, we’re going to look at a special kind of planet called transient exoplanets, and that will be our first shot at studying small planets for gases that might indicate the planet is habitable.


JC: I’m going to ask you one follow-up question, too, Sara, as the generalist. So I am really struck by the notion in your career of the opposition you faced, that when you began thinking about exoplanets, there was extreme skepticism in the scientific community that they existed, and you proved them wrong. What did it take to take that on?


SS: Well, the thing is that as scientists, we’re supposed to be skeptical, because our job to make sure that what the other person is saying actually makes sense or not. But being a scientist, I think you’ve seen it from this session, it’s like being an explorer. You have this immense curiosity, this stubbornness, this sort of resolute will that you will go forward no matter what other people say.
JC: I love that. Thank you, Sara.


Estoy aquí para hablarles de la verdadera búsqueda de vida extraterrestre. No de pequeños humanoides verdes que llegan en ovnis brillantes, aunque eso sería estupendo. Sino de la búsqueda de planetas que orbitan alrededor de estrellas lejanas.Cada estrella en nuestro cielo es un sol. Y si nuestro Sol tiene planetas: Mercurio, Venus, Tierra, Marte, etc., seguramente esas otras estrellas también tienen planetas, y los tienen. Y en las últimas dos décadas, los astrónomos han encontrado miles de exoplanetas.Nuestro cielo nocturno está literalmente lleno de exoplanetas. Sabemos, estadísticamente hablando, que cada estrella tiene, al menos, un planeta. Y en la búsqueda de planetas, y, en el futuro, los planetas que podrían ser como la Tierra, podemos contribuir a resolver algunas de las preguntas más sorprendentes y misteriosas a las que se ha enfrentado la humanidad durante siglos. ¿Por qué estamos aquí? ¿Por qué existe el universo? ¿Cómo se formó y evolucionó la Tierra ? ¿Cómo y por qué se originó la vida que ha poblado nuestro planeta? La segunda pregunta que a menudo se plantea es: ¿Estamos solos? ¿Hay vida ahí fuera? ¿Quién está ahí? Ya saben, esa pregunta ha existido miles de años, por lo menos desde la época de los filósofos griegos. Pero estoy aquí para decirles lo cerca que estamos de encontrar la respuesta a esta pregunta. Es la primera vez en la historia que eso realmente está a nuestro alcance.Ahora, cuando pienso en las posibilidades de la vida por ahí, pienso en el hecho de que nuestro Sol no es sino una de las muchas estrellas. Esta es una foto de una galaxia real creemos que nuestra Vía Láctea se parece a esta galaxia. Es una colección de estrellas unidas. Pero nuestro Sol es uno de cientos de miles de millones de estrellas y nuestra galaxia es una de más de cientos de miles de millones de galaxias. Sabiendo que los planetas pequeños son muy comunes, uno puede hacer los cálculos. Y hay tantas estrellas y tantos planetas ahí fuera, que sin duda, en algún lugar, tiene que haber vida. Bueno, los biólogos se ponen furiosos conmigo por decir esto, porque no tenemos evidencia alguna de vida extraterrestre todavía.Si pudiéramos ver nuestra galaxia desde el exterior y acercar la imagen de nuestro Sol, veríamos un mapa real de estrellas. Y las estrellas destacadas son las que tienen exoplanetas conocidos. Esto es realmente solo la punta del iceberg. Aquí, esta animación es el zoom en nuestro sistema solar. Y verán aquí los planetas así como naves espaciales orbitando alrededor de nuestro Sol. Si nos podemos imaginar ir a la costa oeste de Norteamérica, y mirar hacia el cielo nocturno, esto es lo que nos gustaría ver en una noche de primavera. Pueden ver las constelaciones superpuestas y muchas estrellas con planetas. Hay un parche especial del cielo, donde tenemos miles de planetas.Aquí es donde el telescopio espacial Kepler se centró durante muchos años. Vamos a acercar y mirar a uno de los exoplanetas favoritos. Esta estrella se llama Kepler-186F. Es un sistema de unos cinco planetas. Y, por cierto, de la mayoría de estos exoplanetas, no sabemos demasiado. Sabemos su tamaño, órbita y cosas por el estilo. Pero hay un planeta muy especial llamado Kepler-186F. Este planeta se encuentra en una zona no demasiado lejos de la estrella, de modo que la temperatura puede ser adecuada para la vida. Aquí, la concepción del artista es solo hacer zoom y mostrar lo que el planeta podría ser.Muchas personas tienen la noción romántica de astrónomos yendo al telescopio en la cima de una montaña solitaria y mirando el cielo nocturno espectacular a través de un gran telescopio. Pero, en realidad, tan solo trabajamos en nuestras computadoras como los demás, y obtenemos los datos por correo o descargando una base de datos. Y en vez de venir aquí para hablarles de la naturaleza algo tediosa de los datos y su análisis, y los modelos complejos de computación usados, tengo una forma diferente de explicarles cosas en las que pensamos en relación a los exoplanetas.Aquí un cartel de viaje: “Kepler-186F: Donde la hierba está siempre más roja en el otro lado”. Esto se debe a Kepler-186F orbita alrededor de una estrella roja, y solo especulamos que tal vez haya plantas allí, si hay vegetación que hace fotosíntesis, tiene diferentes pigmentos y se ve roja. “Disfruta de la gravedad en HD 40307g, una Super-Tierra”. Este planeta es más masivo que la Tierra y tiene una gravedad en la superficie superior. “Relájese en Kepler-16b, donde su sombra siempre tiene compañía”.(Risas)

Sabemos de una docena de planetas que orbitan dos estrellas, y hay probablemente muchos más por ahí. Si pudiéramos visitar uno de esos planetas, se podrían ver literalmente dos puestas de sol y tener dos sombras. En realidad, la ciencia ficción tiene algunas cosas correctas. Tatooine de La Guerra de las Galaxias. Y tengo otros exoplanetas favoritos de los que hablar. Este es Kepler-10b, es un planeta caliente, caliente. Orbita 50 veces más cerca de su estrella que nuestra Tierra alrededor de nuestro Sol. Y, de hecho, es tan caliente, que no podemos visitar estos planetas, pero si pudiéramos, nos fundiríamos mucho antes de llegar. Creemos que la superficie es tan caliente como para derretir la roca y tiene lagos de lava líquida.

Gliese 1214b De este planeta sabemos la masa y el tamaño y que tiene una densidad baja. Es un poco caliente. En realidad no sabemos nada sobre este planeta, pero una posibilidad es que sea un mundo acuático, como una versión a escala de una de las lunas heladas de Júpiter que podría componerse del 50 % de agua en masa. Y en este caso, tendría una atmósfera de vapor de espesor superpuesta a un océano, no de agua líquida, sino de una forma exótica de agua, un superfluido. No es un gas, no es un líquido. Y debajo de eso no habría roca, sino una forma de hielo de alta presión, como el hielo IX.

Así que de todos estos planetas ahí fuera, su variedad es simplemente asombrosa, normalmente queremos encontrar planetas Ricitos de Oro, así los llamamos. Ni demasiado grandes, ni demasiado pequeños, ni demasiado calientes, ni demasiado fríos, sino justo el ideal para la vida. Pero para hacer eso, debemos poder mirar la atmósfera del planeta, ya que la atmósfera actúa como una manta que captura calor, el efecto invernadero. Tenemos que poder evaluar los gases de efecto invernadero en otros planetas. Bueno, la ciencia ficción tiene algunas cosas mal. La nave Star Trek tuvo que viajar a grandes distancias a velocidades increíbles a la órbita de otros planetas de manera que el primer oficial Spock pudiera analizar la atmósfera para ver si el planeta era habitable o si había formas de vida allí.

Bueno, no necesitamos viajar a velocidades ‘warp’ para ver otras atmósferas planetarias, aunque no quiero disuadir a los ingenieros de buscar la manera de hacerlo. En realidad podemos estudiar las atmósferas planetarias desde aquí, desde la órbita terrestre. Esta es una imagen, una fotografía del telescopio espacial Hubble tomada por el transbordador Atlantis, cuando partía después del último vuelo espacial humano de Hubble. Instalaron una nueva cámara, que utilizamos para atmósferas de exoplanetas. Y hasta ahora, hemos podido estudiar decenas de atmósferas de exoplanetas, alrededor de seis de ellas con gran detalle. Pero no son pequeños planetas como la Tierra. Son planetas grandes y calientes que son fáciles de ver. No estamos listos, no tenemos todavía la tecnología adecuada para estudiar pequeños exoplanetas. Pero, sin embargo, quería explicarles cómo se estudian las atmósferas de exoplanetas.

Quiero que se imaginen, por un momento, un arco iris. Y si pudiéramos mirar este arco iris de cerca, veríamos que faltan algunas líneas oscuras. Y aquí está nuestro Sol, la luz blanca del Sol se dividió, no por las gotas de lluvia, sino por un espectrógrafo. Y pueden ver estas líneas verticales oscuras. Algunas muy estrechas, algunas son anchas, otras sombreadas en los bordes. Y así es cómo los astrónomos han estudiado objetos en los cielos, durante más de un siglo. Así que aquí, cada átomo y molécula diferente tiene un conjunto especial de líneas, una huella digital, si se quiere. Y así es cómo se estudian las atmósferas de exoplanetas. Nunca olvidaré cuando empecé a trabajar en atmósferas de exoplanetas hace 20 años, cuántas personas me dijeron, “Esto nunca sucederá. Nunca podremos estudiarlas. ¿Por qué lo intentas?” Y por eso me complace hablarles sobre todos los ambientes estudiados ahora, y esto es realmente un campo propio. Así que cuando se trata de otros planetas, otras Tierras, en el futuro, cuando podamos observarlos, ¿qué tipo de gas buscaríamos? Bueno, nuestra propia Tierra tiene oxígeno en la atmósfera en un 20 % de su volumen. Eso es una gran cantidad de oxígeno. Pero sin las plantas y la vida fotosintética, no habría oxígeno, prácticamente nada de oxígeno en nuestra atmósfera. Así que el oxígeno existe, porque hay vida. Y nuestro objetivo es buscar gases en otras atmósferas planetarias, gases a los que no les atribuiríamos la capacidad de contribuir a la vida. Pero ¿qué moléculas deberíamos buscar? En realidad, ya dije cuán diversos son los exoplanetas. Esperamos que esto continúe en el futuro cuando nos encontramos con otras Tierras.

Y esa es una de las cosas en las que estoy trabajando. Tengo una teoría al respecto. Me recuerda que casi todos los días, recibo mensajes de correo electrónico de alguien con una teoría loca sobre la física de la gravedad o la cosmología o algo así. Así que, por favor, no me envíen ninguna de sus locas teorías. (Risas) Yo tenía mi propia teoría loca. Pero ¿quién iba a ir a ver al profesor del MIT? Se lo envié a un Premio Nobel de Fisiología, en Medicina y él dijo: “Claro, venga a hablar conmigo”. Así que me llevé a mis dos amigos bioquímicos y nos fuimos a hablar con él acerca de nuestra loca teoría. Y esa teoría era que la vida produce todas las moléculas pequeñas, tantas moléculas. Como, todas en las que puedo pensar, pero sin ser una química. Piensen en ello: dióxido de carbono, monóxido de carbono, hidrógeno molecular, nitrógeno molecular, metano, cloruro de metilo, tantos gases. Existen también por otras razones, pero justo igual que la vida produce ozono. Así que fuimos a hablar con él e inmediatamente, derribó la teoría. Encontró un ejemplo que no existía. Así, nos fuimos de nuevo al tablero de dibujo y creímos haber encontrado algo muy interesante en otro campo.

Pero volvamos a los exoplanetas, el punto es que la vida produce tantos tipos diferentes de gases, literalmente miles de gases. Y así, lo que hacemos ahora es simplemente tratar de averiguar en qué tipo de exoplanetas, cuáles gases se podrían atribuir a la vida. Y así, al toparnos con los gases en atmósferas de exoplanetas que no sabemos si los producen extraterrestres inteligentes o árboles, o un pantano, o incluso solo vida microbiana simple, unicelular.

Así que trabajar en los modelos y pensar en bioquímica, todo está muy bien. Pero realmente un gran reto ante nosotros es: ¿cómo? ¿Cómo vamos a encontrar estos planetas? Existen muchas maneras de encontrar planetas, varias maneras diferentes. Pero en la que me centro es en cómo establecer una puerta de enlace de modo que en el futuro, podamos encontrar cientos de Tierras. Tenemos una oportunidad real de encontrar señales de vida. Y, de hecho, acabo de liderar un proyecto de dos años en esa fase muy especial de un concepto que llamamos la sombrilla estelar. Y la sombrilla estelar es una pantalla en forma muy especial y el objetivo es volar esa sombrilla estelar que bloquee la luz de una estrella para que el telescopio puede ver los planetas directamente. Aquí, pueden verme a mí y a dos miembros del equipo viendo una pequeña parte de la sombrilla estelar. Tiene la forma de una flor gigante, y este es uno de los pétalos prototipo. El concepto es que una sombrilla estelar y el telescopio podría lanzarse juntos, con los pétalos desplegados desde la posición de estiba. La armadura central podría expandirse, con los pétalos abriéndose en el lugar. Ahora, esto debe hacerse con mucha precisión, literalmente, los pétalos a micras y tienen que desplegarse en milímetros. Y toda esta estructura tendría que volar decenas de miles de km de distancia desde el telescopio. Se trata de decenas de metros de diámetro. Y el objetivo es bloquear la luz de las estrellas con increíble precisión con lo que podríamos ver directamente los planetas. Y tiene que tener una forma muy especial, debido a la física de difracción. Este es un proyecto real en el que trabajé, literalmente, no se pueden imaginar lo difícil. Solo para que me crean, no es solo en formato de película, aquí está una foto real de pruebas para implementar la sombrilla estelar de 2ª generación Y en este caso, quería que supieran que esa armadura central es lo sobrante desde grandes desplegables de radio en el espacio.

Así que tras todo ese trabajo duro donde intentamos pensar en todos los locos gases que podrían estar por ahí, y construimos telescopios espaciales muy complicados que podrían estar por ahí, ¿qué vamos a encontrar? Pues bien, en el mejor de los casos, nos encontraremos con una imagen de otra exo-Tierra. Aquí está la Tierra como un punto azul pálido. Y esta es realmente una foto real de la Tierra tomada por la nave espacial Voyager 1, 6,4 mil millones de km de distancia. Y esa luz roja es solo luz dispersada en la óptica de la cámara.

Pero lo que es impresionante a tener en cuenta es que si hay extraterrestres inteligentes orbitando en un planeta alrededor de una estrella cerca de nosotros y construyen complicados telescopios espaciales como los que tratamos de construir, todos verán es este punto azul pálido, un punto de luz. Y así, a veces, cuando me detengo a pensar acerca de mi lucha profesional y ambición, es difícil pensar en eso en contraste con la inmensidad del universo. Pero, sin embargo, estoy dedicando el resto de mi vida a la búsqueda de otra Tierra.

Y puedo garantizar que en la próxima generación de telescopios espaciales, en la segunda generación, podremos encontrar e identificar otras Tierras. Y la capacidad de dividir la luz de las estrellas para poder buscar gases y evaluar los gases de efecto invernadero en la atmósfera, estimar la temperatura de la superficie, y buscar signos de vida.


Pero hay más. En este caso de la búsqueda de otros planetas como la Tierra, estamos haciendo una nueva especie de mapa de estrellas cercanas y de planetas que orbitan alrededor de ellos, incluyendo aquellos que podrían ser habitable por los humanos.

Y así me imagino que nuestros descendientes, cientos de años a partir de ahora, se embarcarán en un viaje interestelar a otros mundos. Y nos mirarán en retrospectiva a todos nosotros como la generación que primero encontró mundos similares a la Tierra.



June Cohen: Te paso una pregunta, del gerente del Rosetta Misión, Fred Jansen.


Fred Jansen: Mencionaste que la tecnología para ver realmente en el espectro de un exoplaneta similar a la Tierra no existe todavía. ¿Cuándo esperas que esté, y qué se necesita?


Lo que esperamos es lo que llamamos telescopio Hubble de próxima generación. Se llama Telescopio Espacial James Webb, y se pondrá en marcha en 2018, y eso es lo que vamos a hacer, miraremos un tipo especial de planeta llamados exoplanetas transitorios, y será nuestra primera oportunidad de estudiar planetas pequeños para gases que podrían indicar si el planeta es habitable.

JC: Te haré una pregunta de seguimiento, también, Sara, como generalista. Estoy muy impresionada por la idea en tu carrera por la oposición que enfrentaste, cuando empezaste a pensar en exoplanetas, había gran escepticismo en la comunidad científica que todavía existe, y demostraste que estaban equivocados. ¿Qué hizo que siguieras?


SS: Bueno, como científicos, se supone que debemos ser escépticos, porque nuestro trabajo para asegurarnos de que lo que otra persona dice en realidad tiene sentido o no. Pero ser científico, creo que lo has visto en esta sesión, es ser un explorador. Uno tiene esta inmensa curiosidad, esta terquedad, esa firmeza que nos lleva adelante no importa lo que otros digan.

JC: Me encanta eso. Gracias, Sara.



Cash-Landrum Incident, 1980

dimecres, 12/06/2019



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Edinburg, Texas, 1966

dimarts , 11/06/2019

The Edinburg UFO Conference & Festival was inspired, in part, by a very strange event that occurred north of town in 1966. Here is a presentation that was done at the location of the incident by author Noe Torres and Joe Ponce, son of the deputy sheriff that investigated the original case:

Below is the full report on what happened.

Number of witnesses: 8
Location: Farm to Market Rd 490, approximately 4 miles west of U.S. Highway 281.
Just North of Edinburg, Texas
Date: October or November 1966 (exact date unknown)
Time: Approximately midnight

In October or November of 1966, J. R. “Milo” Ponce, a deputy sheriff with the Hidalgo County Sheriff’s Department, received a phone call at around midnight from the sheriff’s department dispatcher, George Rapp. The dispatcher stated that someone had called in to report a group of “disturbed” men standing alongside Farm to Market Highway 490, north of Edinburg, Texas, near Laguna Seca Road.

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Harlingen, 1976

dilluns, 10/06/2019

By Noe Torres, 2014


In the mid 1970s, South Texas experienced a rash of sightings of a large, winged “Mothman” type creature, having some bird-like characteristics. Many witnesses saw the creature, and their panicked descriptions surprisingly agreed in many general aspects.

In a typical description, the creature was described as five feet tall with a dark body; membranous, leathery wings that folded around its body; a wingspan of about 15 feet; dark red eyes; a hairless, gray, gorilla-like face; a bald head; and a beak or snout that extended at least six inches. In addition, the creature emitted a blood-curdling shrill screech.


The terrifying Mothman-like creature was first spotted on a school playground in Robstown, Texas in November of 1975. A couple of weeks later, the creature was seen about 100 miles south of Robstown, in San Benito. Ted Cortez, then police chief of San Benito, told the media that a man rushed into the police station saying excitedly, “I’m not drunk. I’m sober. But I saw it.” Later, two other witnesses contacted San Benito police to report that they had seen a large bird with a bald head, like a monkey.

Shortly thereafter, on New Year’s Day 1976, just outside Harlingen, 11-year-old Tracey Dawson and her 14-year old cousin, Jackie Davies were playing outside their home when they spotted a similar creature standing in a plowed field about 100 yards away from them. Tracey rushed into her house, retrieved a pair of binoculars, and used them to observe a “horrible black bird.” The girls rushed back into the house to tell Lawson’s parent about what they saw, but the adults did not believe them.

The following day, however, Tom Waldon, the stepfather of Jackie Davies, found eerie three-toed tracks that were 8 or 9 inches wide, 12 inches long, and pressed an inch and a half into the hard ground. Tracey’s father, Stan Lawson, who weighed 170 pounds, tried to make a similarly deep impression in the ground with his own foot but found he could hardly make any.

Later, two San Benito policemen, Arturo Padilla and Homero Galvan, traveling in separate squad cards, reported seeing a huge bird with a wingspan of about 15 feet gliding above their town. Officer Padilla later said, “I’ve done a lot of hunting, but I’ve never seen anything like that.” They described it as an oversized stork or pelican.

Big Bird

Another sighting was reported at this time in Laredo. Arturo Rodriguez and his nephew Ricardo were fishing on the banks of the Rio Grande River when they saw the creature, according to media accounts at the time.

The next incident occurred on January 7, when Brownsville resident Alverico Guajardo heard something slam into the outside of his mobile home. Frightened by the sound, the 35-year-old man left his wife and child in the house, grabbed a knife, and ran outside for a look. Getting inside his station wagon for protection, Guajardo positioned the headlights so that they illuminated the area around his mobile home, when suddenly he saw a nightmarish bird-like creature on the ground in front of him. As Guajardo’s headlights shone on the huge bird-like animal, it rose up to its full height and displayed two huge red eyes that struck terror in Guajardo. He later told reporters that he sat staring at those eyes for at least three minutes, after which, the creature issued a horrifying screech and receded into the darkness.

“I was scared,” Guajardo said. “It’s got wings like a bird, but it’s not a bird. That animal is not of this world.”

Another sighting occurred on January 14 in the Willacy County town of Raymondville. 26-year-old Armando Grimaldo was enjoying a smoke in his mother-in-law’s backyard when he heard what sounded like the flapping of bat wings, followed by a whistling or screeching sound. As he rose up out of his seat to investigate, he felt “something with claws” grab him from behind. Running toward a nearby tree and struggling to free himself from the creature’s grasp, Grimaldo felt his clothes being torn away from his body as he ran. Shortly thereafter, the creature broke off its attack and disappeared into the night. Grimaldo’s neighbors found him in the yard shaking and screaming with his clothes in shreds.

Yet another sighting was reported some 300 miles away, in Eagle Pass, Texas, where 21-year-old Francisco Magallanez claimed he was attacked by the creature. Although Magallanez admitted that he had been drinking at the time of the incident, a physician who examined him confirmed that he had suffered scratch marks such from an animal or bird.

On February 24, a creature matching the previous descriptions was seen in San Antonio by three teachers. The teachers later picked out a picture of the extinct flying reptile Pteranodan as matching the creature they saw. Pteranodan, the largest of the pterosaurs with a wingspan of up to 25 feet, is believed to have become extinct at about the same time as the dinosaurs. They are viewed as the precursors of modern-day birds.

Following the San Antonio sighting, no further media reports seem to have been filed about the creature. As suddenly as it had appeared, the so-called “big bird” had vanished. Still, it remains deeply etched in the memories of many South Texas residents who lived through the creature’s brief “reign of terror.” Afterward, many legends and tales about the creature spread among the local population.

Scientists and others attempted to explain away the unearthly winged creature, insisting that it was likely just a large stork, a heron, or other large bird. However, those few individuals who stood face to face with the creature, staring at the terrifying large red eyes set in the ape-like face, never “bought in” to the mundane explanations. The words of eyewitness Alverico Guajardo, who called it “not of this world,” bear strong testimony to an encounter with something out of the ordinary.

Despite the theories and speculations, the mystery of this strange creature has never been solved. It remains filed away in the recesses of our imagination, awaiting a time when we ourselves may be confronted by the sound of large, leathery wings rustling outside our window late in the night, followed by an other-worldly high-pitched screech.


Between West Columbia and Damon, 1965

diumenge, 9/06/2019

On Friday, September 3, 1965 at 11 p.m. Brazoria County Chief Deputy Sheriff Billy E. McCoy and Deputy Sheriff Bob Goode of Angleton, Texas were patrolling the West Columbia area of Brazoria County (South of Houston), on Highway 36 between West Columbia and Damon (29°16’04.7″N 95°43’05.7″W).

McCoy spotted a brilliant purple glow at horizon level beyond vast pasture land and was unable to identify the source. The deputies headed south with Goode driving and McCoy to the driver’s right. The object was off to their left. The glow soon became discernible as a bright, round light.

Next, McCoy noted a somewhat smaller less powerful blue light seemingly “emerge” from the larger purple light and move some distance to its right. He later realized this effect resulted from the triangular object making a 90-degree turn so that it “faced” them, and the blue light, which had been parallel with and “behind” the purple one, now became visible.

Goode had maintained until this time that the lights were oil field lights, but McCoy disagreed. McCoy then noticed that both lights had apparently risen simultaneously slightly above the horizon level, and Goode then conceded that the objects could not be oil field lights. Goode swung the car around for a better view as they were now directly opposite the light, with McCoy, the passenger, now on the side closest to the pasture.

Based on knowledge of the terrain and upon further investigation in daylight, McCoy and Goode estimated that the object at this point was 5 to 7 miles from the highway.

McCoy feels certain that within the next three or four seconds, after the car was turned around, the object traversed the distance from its initial position to a spot approximately 150 feet from the highway, 100 feet above the ground level, and parallel to their car.

The vehicle and its surrounding area was brightly illuminated in purple light. The UFO now being only 100 feet away, it was evident that there were not two separate objects, but that the two lights were opposite ends of one enormous, triangle-shaped object. Later, McCoy described the object to the Air Force:

“The bulk of the object was plainly visible at this time and appeared to be triangular shaped with a bright purple light on the left end and the smaller, less bright, blue light on the right end. The bulk of the object appeared to be dark gray in color with no other distinguishing features. It appeared to be about 200 feet wide and 40-50 feet thick in the middle, tapering off toward both ends.”


The two patrolmen made a break for it with the object almost directly overhead. Driving at speeds of up to 110 mph, they finally found themselves free of the object. As they fled the scene, they could see the object maneuver back to its original position in the old fields. After gaining their composure, they decided to return to the scene.

Arriving at the spot where they first saw the object, they observed the object begin the same routine as before. Frightened, they sped away.

They reported their unusual encounter to Ellington Air Force Base. The subsequent investigation was conducted by Major Laurence Leach, Jr. who later wrote about the case, “There is no doubt in my mind that they definitely saw some unusual object or phenomenon… Both officers appeared to be intelligent, mature, level-headed persons capable of sound judgment and reasoning.”


There has been no explanation for what the two patrolmen saw that night, but on an interesting side note, this case occurred on the same night as the celebrated UFO Incident in Exeter.




Statement given to the Air Force by Chief McCoy:




Deputy Sheriff Goode and I were driving south on Highway 36 from Damon, Texas toward West Columbia at about  11:00 p.m. on Friday, September 3, 1965.

When we were about two or three miles south of Damon, I saw a very bright purple light stationary on the horizon about 5-6 miles away and southwest of our position. After a few seconds a smaller blue light appeared out of the larger purple light and traveled to the right of the purple light, pausing momentarily in two distinct positions before becoming stationary. The lights then floated upwards to an angle about 5-10 above the horizon. They remained at a distance of 5-6 miles and we were unable to distinguish any other features other than the two bright lights.

We turned the car around and Deputy Sheriff Goode looked at the lights through binoculars. We decided to investigate further and headed back toward Damon to look for a back road to take us nearer the lights. After traveling about 3/4 of a mile on Highway 36 we slowed down. Goode had his window open (rolled down) and looked through the binoculars again and the lights appeared to still be in the same position.

We slowed down to almost a stop off the edge of the highway and while watching the lights they started coming toward us at a rapid speed. The object came up to the pasture next to the highway about 150 feet off the highway and about 100 feet high. The bulk of the object was plainly visible at this time and appeared to be triangular shaped with a bright purple light on the left end and the smaller, less bright, blue light on the right end. The bulk of the object appeared to be dark gray in color with no other distinguishing features. It appeared to be about 200′ wide and 40-50 feet thick in the middle, tapering off toward both ends. There was no noise or any trail. The bright purple light illuminated the ground directly underneath it and the area in front of it, including the highway and the interior of our patrol car. The tall grass under the object did not appear to be disturbed. There was a bright moon out and it cast a shadow of the object on the ground immediately below it in the grass.


Deputy Sheriff Goode was in the driver’s seat with his left arm laying in the open window. Although he was wearing a long sleeved shirt and a coat, he later said that he felt the heat apparently emanating from the object. We immediately put the car in motion and headed toward Damon as fast as we could go. While traveling at speeds up to 110 mph, toward Damon, continued to watch the object out of the back window of the car. It appeared to remain in the same position for approximately ten seconds and then move off in the direction where we first saw it at a very high speed. There was no noise. While it was in motion the smaller blue light on the right side disappeared entirely and the larger purple light became smaller but retained its brilliance apparently caused by its movement away from us. After arriving at approximately its original position, it went straight up in the air and disappeared at 25-30 above the horizon.
When we got to Damon, we drove slowly through the town, discussed what we saw, and decided to go back to the area and see if the object was still there. We were both scared but still wanted to find out what it was. We decided to take the old Damon-West Columbia road which would put us closer to the area where we first saw it. However, we traveled the full length of this road until we turned off to go back on Highway 36 and we didn’t see anything.
We headed back toward Damon on Highway 36 and when we got to the area where we first saw the bright lights we again saw the bright purple light on the horizon and the smaller blue light again appeared out of the larger purple light. After the blue light moved exactly like it did the first time and became stationary the lights floated in the air at about 8-10 degrees. We decided to leave the area because we figured that the object would start coming towards us again.


We returned to West Columbia and told the City Judge of West Columbia, Jim Scott, about what we saw. Jim and his family went over to the area and remained for about an hour and a half but they didn’t see anything.

I returned to the area the following 3 nights at approximately the same time and have not seen anything like what we saw the first night. I have been unable to come up with any plausible explanation of our sightings. There are no ground lights in this area which could cause a reflection. I am positive that the object was not any type of aircraft that I know to exist and I have never seen anything like it before.

I have been a Brazoria County Deputy Sheriff for 11 years and now occupy the position of Chief Deputy Sheriff. I am 38 years old. Deputy Sheriff Goode has been with the department for 10 years and is 50 years old. Neither of us had anything to drink on the night we saw the lights and the object. We were working the football game at Sweeney on this night.

The area where we saw the object is in Goode’s area of responsibility and we were on patrol duty. The night was clear and there were no clouds or haze. There were some spots of ground fog but not in the area where we saw the object.


Texas UFO Museum & Research Library


Several police officers, 1966

dissabte, 8/06/2019

Summary: E of Akron Deputy Sheriff Dale F. Spaur and associate Wilbur Neff saw a 30-45 ft metallic object approach over the treetops from the woods, bathing the witnesses and the whole area in light while making a transformer-like hum, then headed E and they gave chase in the patrol car at speeds up to 105 mph for 85 miles. Officer Wayne Huston about 35 miles to the ESE saw the object he described as ice cream cone-shaped, point downwards, approach from the W and pass overhead at about 800-900 ft height with Spaur and Neff in pursuit to the SE and he joined them near Unity, Ohio, with the object about 1/2 to 3/4 mile ahead of them, reaching the Penna. state line at 5:35. They lost sight of object at Brady Run Park regained it in Bridgeport, Penna.

At about this time officers Lonnie Johnson and Ray Esterly in Salem, Ohio, saw 3 jet fighters attempting to intercept a bright object at about 10,000-20,000 ft about 25° elevation to the E for about 2 mins. In Conway, Penna., at 6 a.m. they met with officer Frank Panzarella who had been watching the object for 10 mins to the E or SE which he described as 25­35 ft half-football-shaped object at about 1,000 ft height (or 1,500-2,000 ft according to the others), when it stopped in the NE towards Harmony, Pennsylvania, then rose. They watched as the object climbed to about 3,500 ft to the left of and level with the quarter moon in the ESE (which was at about azimuth 116° elevation 14° and 11 % illuminated at 6:00 a.m.) and Venus (at 122° azimuth 22° elevation) and it passed near a 707 airliner taking off from Pittsburgh Airport and disappeared shooting up vertically at about 6:10 

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