viernes, 13 de septiembre de 2013

Voyager 1 alcanza el espacio interestelar

Aparentemente desde el 25 de agosto de 2012.

El 8 o 9 de abril de este año la sonda espacial Voyager 1, de 39 años y que está a una distancia de diecinueve mil millones de kilómetros de la Tierra, fue alcanzada por una onda de plasma proveniente de una expulsión de masa coronal en el Sol, probablemente ocurrida en marzo de 2012.
Dicha onda puso a vibrar el detector de plasma del Voyager, como una cuerda de violín, a una frecuencia tal que permitió a los científicos determinar que la densidad de dicho plasma era unas 40 veces mayor que la existente en las capas exteriores de heliosfera.
Esto permitió establecer la fecha de agosto del año pasado, cuando se detectaron por primera vez las partículas de la onda de plasma (viento solar).


Voyager 1 Has Left the Solar System:

Voyager Reaches Interstellar Space:

Voyager Captures Sounds of Interstellar Space:

Message to Voyager: Welcome to Interstellar Space:

NASA News Conference: Voyager Reaches Interstellar Space:

martes, 3 de septiembre de 2013

Del Big Bang a la energía oscura (From the Big Bang to Dark Energy)

Se trata de un curso en linea de 4 semanas enseñado en idioma inglés, con varios vídeos semanales, quices y exámenes parciales. Solo necesita algo de matemática, física y unas 10 horas semanales de su tiempo. Parece muy interesante y de un nivel para universitario. Inicia hoy, se lo recomiendo. Podemos tomarlo juntos y así podremos estudiar y apoyarnos.

I made this illustrated PDF from the first video lecture of the course (Coursera) From the Big Bang to Dark Energy  by Hitoshi Murayama, from The University of Tokyo, in which I am enrolled now. Anyone can do it from the provided Subtitles (srt), just eliminating the video codes and adding the images from the PDFGraphics. It is a nice working tool; I used it in Volcanic Eruptions: a material science, with good results. The course starts today, but still there is time to enroll during this week.
Remember that blogger (and word) may translate this text to many languages.

Week 1: From daily life to the Big Bang

Introduction: Course Outline (08:37)

Hi, I'm Hitoshi Murayama.I work at the University of California, Berkeley as well as at the University of Tokyo. And I'm, I'm giving four lectures about the recent status of our understanding about the universe. So, the title of my lectures is From the Big Bang to Dark Energy. And the Big Bang, as everybody knows, is the beginning of the universe. So, in most of my lectures I will be talking about how we understand how the universe began. Starting from where things start today and gradually move back in time and try to, reach as much as possible at the very beginning of the universe. But towards the very end of my lectures, I'm going to talk about the future of the universe that has to do with this other part of the title called dark energy. So, in in our understanding of the universe has made a huge progress in the last 15 years or so. And what we used to think we knew about the universe is now totally wrong and outdated. A sort of undergoing a big revolution right now. So, what I would like to communicate to you in this lecture is, is what we have learned in the last, you know, 20, 15 years. And, and what we think we know about the Beginning of the universe as was the future of the universe. And we try to put that together in, in a bigger context. So, I organized this content in four lectures, as I said already. And it will be extremely helpful if you know some calculus but I also organized the content in such a way that if you want to skip some of the equations, you can do so. And still you can probably get some conceptual understanding of what's going on there. But if you do know Calculus, then you can follow some of the equations and get a deeper understanding that way. And the homework will also be organized in a way that you have some conceptual problems, which you can understand without the need of Calculus. And some other more advanced problems where you really need to do some math and, and algebra to work things out. So, hopefully this kind of combination would reach you in, in a, to a much, much wider audience that way. So, many of you who may not have that kind of background you can still get something out of my lectures, hopefully. And if you do, you can get a lot more that way. Okay? So, that's the way we'd like to get started. As I said, From the Big Bang to Dark Energy, the kind of questions we would like to ask in these lectures are really, sort of, questions you might have had when you were a little child. So, if you go to, let's say vacation and camping, you watch up the star in the starry sky in the evenings and, of course, one of the sense we always get is kind of awe. We always feel that the universe is so beautiful, stars are so beautiful, and we’d like to at least understand what's going on there. And you tend to get into really philosophical thoughts just by looking at the stars. And this is kind of questions you might have asked when you were little. How does the universe began? So, this is such a big universe out there? But, you know, we hear that this was actually the beginning, that's the big bang. So, what exactly was the big bang?
How did the universe begin? And the next question might be what is its fate? So, we live in this universe and, of course, for natural reasons we would like to understand where we're heading to. And that is about the fate of the universe. And that has to do with this last part of my lectures called dark energy.
What is it made of? And for us to understand how the universe works, of course, we need to understand what the universe is made of. And as we'll tell you as we go along, we used to think that the entire universe was made of kind of atoms, we are made of as well. But that actually didn't turn out to be the right understanding and you will see that, atoms make up only less than 5% of the entire universe. And the rest is actually unknown. So, we will talk about these things as well.
And what are its fundamental laws? And of course, for us to understand how universe works, we need to understand its basic laws. So, there are laws of physics that tell you how things fall, how things move and so and so forth. And there are also laws that would govern the evolution of the universe as well. So, we will talk about some of these things. Finally, of course, we are very curious about where do we come from?. And, and in order to understand where we come from, of course, the part of the question may be biological or evolution but a part of the question also has to do with what are we made of and where did our ingredients come from? Where did the chemical elements come from and why do we have matter in the universe? I will also mention that anti-matter, which could have been the anti-verse, is actually not there so that's the kind of question we would like to understand as well. And all of these questions, as you see on this list, used to be in the realm of, say, theology or philosophy. But now we can address some of these really big questions, fundamental questions in the realm of science. And that's the kind of progress we are making these days and that's extremely exciting. So, I'd like to tell you what these excitements are as we go along. So, as I told you already I organize my lectures in four lectures.
So, the first one today is from daily life to the Big Bang. And when you think about the universe you might have this impression that well, It’s far out there, it has nothing to do with me, but that's not true at all. What we experience in daily life actually has a lot to do with what's going on in the universe. And that eventually leads all the way back to the big bang. So, that's the first lecture I am going to present today.
In, in the second lecture we'll talk about the birth of elements and something you haven't heard about recently the Higgs boson. So, if you think about where we come from, we're made of chemical elements. And unless there are chemical elements out there in our universe we couldn't have been possibly be born. So, where do they come from? That actually turns out to be a real scientific question we can ask today. And I can tell you about our recent understanding about this. And it does have to do with this newly discovered Higgs boson that was discovered in July fourth 2012. And without this Higgs Boson we could not exist. So, that's the connection I would like to make in my second lecture.
In the third lecture, we get into more mysterious side of the Universe. The first one is called dark matter and this dark matter is actually a bulk of matter in a Universe. But we still don't know what it is. At the same time, though, we know the dark matter had played a very important role in forming the universe as we see today. And without it again, we could not have existed in this universe. So, we'd like to talk about what it may be and what we're looking for so that we may gain some understanding on the nature of dark matter as we continue our research program. And the second half of the lecture will be antimatter. And antimatter may sound like something that might show up in a science fiction movies. But they do exist, we can even make them. So, they actually must have been born at the very beginning of the universe in the Big Bang. But fortunately antimatter doesn't seem to exist today. And that's actually very important as well. So, where did it go? So, that's another very fundamental question about where we came from, how we come to exist and so absence of antimatter is a very important question, it turns out.
In the final lecture, the lecture number four, we talk about inflation and dark energy. So, if we really want to go back to very, very beginning of the universe, we think it's still hypothesis. But there's a very good evidence for it. We think there was a period called cosmic inflation that made the universe that was born at a much, much smaller size than an atom to a macroscopic size we see today. That's a tremendous expansion of the universe and that idea has been borne out with the latest data. So, we will talk about that and that was what happened at the very beginning of the universe. But it so happens that universe seems to have started yet another stage of inflation very recently. And that that has to do with this last subject called dark energy. And depending on the nature of dark energy, the universe may have an end. Or it may continue expanding forever. We don't know which one is the right Future yet, but Dark energy is definitely the key to that question. So, we'd like to talk about this very beginning of the universe as well as what might be waiting for us in the future that has to do with the nature of Dark energy. So, that will be my fourth lecture. So, that's the way I organize my lectures for this course.

domingo, 1 de septiembre de 2013

Llegó el máximo solar 24, pero no muy activo

Las predicciones para el pico de actividad de este máximo solar, de acuerdo con lo esperado en el ciclo solar, cuyo promedio es de 11 años, suponían que ocurriría a mediados de este año 2013.
En efecto parece que ya llevamos varios meses en el máximo número 24, pero la actividad solar reflejada en el poco número de manchas solares y erupciones solares, harán de este máximo, uno bastante disminuido, si se compara por ejemplo con el ciclo 19 (201 manchas solares en junio de 1958) y el ciclo 21 (164 manchas solares en diciembre de 1979). Posiblemente este máximo alcance un número de manchas solares por día, entre 70 y 100.
El máximo del ciclo anterior número 23 produjo un número modesto de manchas solares (121 en enero de 200), además de un profundo mínimo a finales del 2008. No se observaron manchas solares durante 266 días de los 366 del año (73%). En el 2009 no se observaron manchas solares durante 260 días (71%).

Resumen de actividad solar
Los científicos solares han llegado a la conclusión de que luego de un profundo mínimo  generalmente sigue un máximo débil, que es lo que parece estar sucediendo ahora (ciclo 24), con una particularidad que ya ha sucedido algunas veces; un doble pico, el primero en el año 2013 y el segundo en el año 2015.
No quiero despedirme sin hacer una breve alusión a lo que se dijo sobre el sol antes del 21 de diciembre de 2012; las especulaciones apocalípticas resultaron totalmente falsas y algunas veces mal intencionadas. Todo fue simplemente una campaña de desinformación basada en creencias y supersticiones, no en hechos verificables.  Más bien todo lo contrario, este máximo solar parece que será muy mansito.
Casi nada sustituye al análisis científico de la naturaleza y a la correcta, leal y verídica información hacia el público,  como lo hacen los centros de investigación especializados y de reconocido prestigio.  

Sea muy crítico con los sitios de internet que visita.