Quanto Magazine

How many planets are there? (2/3)

We spoke a few days ago what one immediately thinks for “planet” when you hear that word. Mercury, Venus … etc, until a few years ago, it was certainly no more than ten. In recent decades there have been dozens of space missions to different planets, comets and satellites. The results of these explorations have largely been available to the general public that have seen detailed images of Mars sent by the probes Viking and Mars Pathfinder.

But even though the exploration of the solar system still has a long way to go, the idea of worlds (and life) around other stars is surely back to the dawn of human imagination. Interestingly the first two planets detected are not found orbiting a quiet star (such as our beloved Sun), but in a strange place
where no one would have thought to find such a thing: the pulsar PSR 1257 +12 that is in the Virgo constellation about 2,000 light years from us. It came to fame in 1992 for harboring two planets of a size about twice that of our Earth. The discoverers of such a finding were the Polish Alexander Wolszczan and Canadian Dale Frail.

The pulsars (see the artistic recreation of one on the right) are tiny neutron stars that spin at breakneck speeds (specifically PSR B1257 + 12 has a diameter of about 30 km and a rotation period of 6 milliseconds, or that is, rotates about 160 times per second!). A curiosity is that both the discovery of this pulsar and observations that revealed the presence of these exoplanets were made at the Arecibo radio telescope in Puerto Rico. Antenna we have all seen in the movie “Contact” based on the novel by Carl Sagan. Interestingly this telescope today provides data project SETI @ home that seeks to detect radio emissions by extraterrestrial civilizations.

The method to detect these planets around pulsars is quite simple to understand. Pulsars have a period of extremely regular rotation, so the radio broadcast we received with a radio telescope has a fairly well-defined period. One example is the following video showing an auditory representation of electromagnetic pulses that are detected in some famous pulsars:

Now imagine a small planet revolving around one of these pulsars. This pulls gravity on the planet in the same way that the planet pulls on the pulsar, or in other words, both bodies will revolve around the center of mass system common. In the case of system PSR B1257 + 12 and the largest of its planets (called B as the second in distance) the center of mass is about 700 km from the pulsar (remember that its diameter is about 30 km). To calculate this figure just we need to know that the planet B has an estimated mass 4.3 times the mass of Earth and is orbiting at about 0.36 astronomical units pulsar).

From our reference system on Earth, the pulsar will have a very small oscillation around its center of mass, which will add to the intrinsic rotation of the neutron star. Thus the periodic pulse emitted will be modulated in turn by this oscillation another almost imperceptible.

The residue left after subtracting the period of the pulsar can determine the axis of the orbit of the object that produces the disturbance (the supposed planet), as well as having an upper limit on its mass.

Of course all this is complicated when instead of having a single planet we have a planetary system with several components. Each planet then exerts a little tug on the pulsar and slightly modulate its intrinsic pulse. So it becomes even more complicated demodulation. This is the case of PSR B1257 + 12 in which 4 planets have been detected in different sizes and orbital distances.

The advantage of this method is that it is quite accurate because the pulsar signals can be digitized with enough time to be picked up by radio telescopes resolution. In addition to being the natural clocks so precise pulsar is easy to detect tiny anomalies in the period due to relatively small planets, even smaller than Earth. No other method to discover planets as small.

The disadvantage is that there are not many known pulsars which severely limits the potential planets to discover. In fact, today, less than a dozen extra solar planets have been discovered using this technique. In addition, another point that takes some of the interest the matter is that all these planets would not harbor life almost certainly. Pulsars are neutron stars that remain as residue after the recent explosion of a massive star as a supernova . Therefore any planet in the area would have to be formed at some time after the explosion and would be subjected to intense high – energy radiation that would prevent the formation of life.

I guess I still need to answer the question. We’ll save that for next week.

Archaeoastronomy: Newgrange

Archaeoastronomy combines astronomy with archaeology and history to unravel the mysteries and possible intentions of buildings and the legacy of past civilizations.

The examples are abundant, prehistoric buildings whose orientation is related to the position of the stars, such as Stonehedge or some structures Maya . The sun worship and knowledge of the solstices and equinoxes is present in many cultures and civilizations now extinct, was later replaced by purely religious holidays such as Hanukkah  Jewish, the Christian Christmas or the Feast of San Juan (night bonfires at many points of the Spanish coast)

Others, such as the Pyramids of Egypt , are always surrounded by speculation and theories that emerge around them. However, given the number of stars it is not difficult to guess or experiment new hypotheses that fit the layout of a given complex. Archaeoastronomy is responsible for taking the necessary measures validated on the ground and running the relevant calculations on the exact position of the stars at stake during the time of execution of the works.

Today we will deal with one of these constructions, less known than others and yet very interesting for several issues.

Newgrange was accidentally discovered in 1699 and described as “a cave” ; it was not until the 60s when it was excavated and restored thoroughly.

Perhaps the first thing that draws attention is its age. Carbon 14 tests locate their origin between 3300 and 2900 BC (period neolithic ), the order of 500 years prior to the Great Pyramid of Giza and almost 1000 to Stonehedge .

Located in the eastern part of the current Ireland is part of the neolithic complex of Brú na Bóinne . The outward appearance is of a hill surrounded by a wall. Inside the mound, made of stone carved with peat inside, runs a passage of about 18 meters, up to a third of the diameter, leading to a cross – shaped chamber. Most of the stones come from nearby, but granite and quartz had to be transported from more distant areas, which indicates that the location was specifically chosen.

The interior ceiling dome shaped primitive rises to about 6 meters. The fit of the stones has remained intact for more than 5000 years of construction, avoiding completely efficient filtering water and the effect of erosion.

The finding inside the cremated remains of 5 individuals indicates its more than likely use as a necropolis.

The tumulus is oriented astronomically so that each year, on the morning of the winter solstice, sunlight enters through an opening above the entrance, walking the corridor 18 meters to illuminate the floor of the chamber for 17 minutes. The accuracy of the guidance brings credibility to the intention of this “birth”, probably based on the observation and measurement of the inhabitants of the area during the Neolithic. Decoration stones has the spiral ( of course solar symbol) as recurring element.

You can see all these details with great quality in the video that accompanies the entrance.

You can only be accessed within Newgrange through guided tours, a service specially requested for the solstice. I remember my visit to the tumulus the existence of a draw for invitations to date as indicated. Definitely a highly recommended visit if you pass through Dublin.

Gustav Dalen

A good part of our “technological world” passes every day unnoticed, either by the force of habit, or because there are so many technologies that we take for granted. Many everyday technological developments were at one time engineering triumphs, and before that, the science or dream of a visionary.

One of the greatest awards for a technological advance is the Nobel prize. The history books say that the Swedish Alfred Nobel, was tormented by his fortune amassed in the industry arms of dynamite (of which he was the inventor) and wanted to remove the awards that bore his name. According to his testament :

“The totality of what that remains of my fortune be disposed of as follows : capital, invested in securities insurance by my executors , shall constitute one fund whose interest will be distributed each year in the form of prizes among those who during the year preceding have made the greater benefit to mankind. These interests are divided into five parts equal, which will be distributed in the following way: one part to the person who has made the discovery or invention more important within the field of physics; one part to the person which has made the discovery or improvement more important in the chemistry ; one part to the person who has made the discovery more important in the field of physiology and medicine ; one part to the person who has produced the work most outstanding of trend idealist in the field of literature , and one part to the person who has worked more or better in favor of fraternity between the nations , the abolition or reduction of armies existing and celebration and promotion of processes of peace . the awards for the physics and chemistry will be awarded by the Academy Swedish of the Sciences , that of physiology and medicine will be awarded by the Institute Karolinska of Stockholm ; that of literature , by the Academy of Stockholm , and the advocates of peace , by one committee formed by five people elected by the Storting ( Parliament ) Norwegian . It is my express wish that , by granting these awards , not be in consideration the nationality of the candidates , but they are the most deserving those who receive the prize , whether Scandinavian or not. “

It is since then very complicated the role of the different institutions responsible for choosing the winners based on their contribution to the benefit of humanity, and more when those contributions can not be neither obvious nor immediate.

For example, the prize Nobel of Physics has moved always between the extremes reflected in the will of Alfred : discoveries and inventions. The award has been split between work of theorists such as Van der Waals or effect Photoelectric of Einstein and others with more practical work such as the instruments optical of Michelson or telegraphy by Marconi and Braun. Today we’ll talk about an unknown Gustaf Dalen.
The prize awarded to Gustaf Dalen in 1912 may be one of the most curious of all the history of the award. It could favor him his nationality was Swedish and also the fact of that during that same year lost sight in a serious accident during a test with acetylene, a very dangerous explosive substance. What you do not put in doubt is that he contributed to saving lives and therefore the benefit of humanity .

He born in a farm and supported by his mother her was able to study. He constantly invented things.

The main achievement of Gustaf came from for his work with acetylene. Capable of producing the lights in headlights. Developing one new porous materials, improving the safety of the storage of acetylene and discovered the way in which the flame of acetylene works.

In addition it incorporated one valve solar, which was at the tune the only lamp to work during the night. An invention that the own Edison doubted that would work and that required a demonstration to the patents office . With all this work he managed to reduce the consumption of the lamp by 94%.


The “Dalen Light”, is thus named in honor of its inventor. It increased the efficiency of the headlights, not depending on the then little reliable supply electricity. With this technology, headlamps immediately illuminated Sweden and the channel of Panama till the 1960’s. Even in 1980 an electrified lighthouse Blockhusudden was discovered which a valve that had been running continuously since 1912 without one single revision!

In spite of his accident Dalen continued his work until his death in 1937. He was an active participant in public life and policy of his country was a member of the Royal Academy Swedish of Sciences and of Science and Engineering .

Refs and photos:


http://en.wikipedia.org/wiki/ Gustaf_Dal % C3 % A9n


Interview with Christopher Fernandez Pineda

Here at Quanto we wanted to know something about the history of The University of Madrid. So we went to talk to Christopher D. Fernández Pineda, and after a bit of conversation discovered that the story of the classroom is the history of the Faculty, its spirit and its people. Professor Fernandez Pineda tells the liveliness that characterizes some of the events that happened at the Faculty in the sixties in the twilight of the Franco dictatorship. Here’s what he said.

“It was a really difficult time, at the Faculty hard times were lived because they were already the last years of the dictatorship and probably the university was the only place where you could talk a little freely, but you had to be careful, because anything that was said could be heard by the police in class. There were people in class sitting and we knew they were cops. At that time there was a police headquarters here at the Faculty. In the old department there was a thing called the police Faculty of Science, and it had about thirty guards there .. and three or four secret policemen, one of them was known as ‘the vampire’. They were hard times for both the teachers and the students.”

“The photos that I will show you was taken in the optics laboratory and through cracks in the window with shutters he pulled”.

Here’s the bridge, and water hose to the fourth floor, which was where the delegation of students was. The water had green paint in it, it made it so that you could not walk down the street. You were painted green and people knew that you had been in the mess. Of course there were democratic cravings. By then the Faculty of Physics was reputed to be a faculty which strived for this. The Faculty has changed a lot in that respect. Then, of course, when democracy arrived, the University was not a political discussion forum.”

In the classroom Magna, currently 1 D. Christopher received his first class and also taught his first class as a teacher. Then he tells some anecdotes about this classroom.

“The Classroom 1 has a great democratic tradition. I remember coming to class and sometimes could not teach because there was a hullabaloo and then a show of hands was made. Those who wanted to give class to raise their hands, those who do not want to teach raise your hands.. it’s a vote… One day, some students went to the dean and said they wanted elections. I was very young then. What happened next is that there was an election planned for May 1 … Sure, I got there on May 1, at that time we wore gowns, I put on my robe and went to class. When I got to school I found the classroom and the hallway and all full. Then I saw the police turn to me and say: “where are you going?”, and I answer that I presided over elections and they took me to the barracks. I told them to call the Dean and ask him why this had happened and why I’d been shut up there with thirty policemen. Eventually they called the Dean, but they left me a couple of hours there. Good thing they did not take me to the Directorate General of Security. So the next time elections were held, students again asked me.

“In my time there were very few professors, there were five or six compared to forty now. I think the faculty in education had a fairly acceptable level. Right now, it is working well and is being published in many journals. But during the time of the dictatorship, the issue of Physics in Spain was very weak. This has been a very strong evolution from the seventies or so. Physics has risen and, in general, Scientific and number publications. People began to publish abroad also because we were very scared to publish here. Today, here at the Faculty there are very good level. I repeat the phrase of D. Carlos Sánchez del Río, Dean of the Faculty few years ago. He promised to find someone who knew about any subject of Physics in 24 hours, here, within the Faculty. The weirdest thing that may be of Physics, in 24 hours we will look for one of the Faculty of Physics at the Complutense who knows the subject. This faculty is very complete, the average value is quite high. We are being published enough.”

“In the old system of recruitment of staff it was different. There was one thing, which in my view was very important, which is the thesis. I did a dissertation. Before when you finished the essay you could talk to people in the department, and you got a little job as you started to investigate. In that year you had time to start researching the literature, start driving magazines and to work independently. It gave you a good basis for further work.The first salary I had was 22,000 pesetas per year, some 1,800 monthly. and when I had graduated I had a salary of around 3,000 pesetas a month, but no Professor earned much then.”

Christopher Fernandez Pineda holding the chair which was once occupied Don Julio Palacios. Many other issues were discussed in our talk with Professor Fernández Pineda, a fascinating man. 

How many planets are there? (1/3)

This question automatically activates our hippocampus and transports us to our childhood where one day we learned Image of Saturn captured by Voyager 2the planets of the solar system: “Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto.” All this only altered by the grand finale of Pluto, our subsequently banished distant planet. The 9 planets of the Solar System  where it appeared, may have included the image of Saturn in false color (see afterwards that it was a composition of green ultraviolet light and violet) taken in 1981 by the space probe NASA ‘s Voyager 2 (see photo right).

Since the discovery the last and most timid on the list (Pluto) was back in 1930, one wonders how planets are discovered. An important detail of the discovery of Pluto it is that, as usual in astronomy, it was not by chance. The search for Pluto was a result of the discrepancy between the observed position of Neptune and the theoretical position of accurate astronomical calculations. In fact, some similar calculations eight decades ago by John Couch Adams and Urbain Le Verrier independently, led to the discovery of Neptune, which also seemed somehow alter the orbit of Uranus.

The discoverer of Pluto, who changed the long standing list of planets, was Clyde Tombaugh. From the Lowell Observatory in Arizona he discovered the slow movement of the icy dwarf and ran out giving it the name of the god of the underworld.

He used this device, known as blink comparator, which is a completely obsolete in our modern times. If someone wanted to see live a living relic of this device can be found in the museum of Lowell Observatory (pity there is not one in the collection of the National Geographic Institute).
Another story of Pluto is that of a girl of 11 years. Specifically Venetia Burney (pictured), a student at Oxford at that time who proposed Pluto as possible name for the newly discovered star.

I can not end this first entry without mentioning the fall of Pluto of Olympus in 2006. The IAU decided that Pluto should no longer be a planet because it was too different from the others. In particular it is too small and far away. Possibly the straw that broke the camel’s back was the discovery in 2005 of the trans – Neptunian object Eris, which is actually larger than Pluto. This forced the IAU in 2006 redefined the term planet, to prevent about 25 objects similar to Pluto from being classed as planets. I guess kids today can thank the IAU to spare them memorize more than 30 planets!

In conclusion, Pluto since 2006, along with 4 other colleagues (Ceres, Eris, Makemake and Haumea) have been classed as dwarf planets, and as a result, the number of planets that hypothetical children present should memorize (if educators do not believe too stressful) is eight. So (for now) the answer to the title of the entry is eight .

In my next post we will go a little beyond Pluto to see how planets of other stars are discovered.

Great Scientists: Hendrik Antoon Lorentz

This Dutch farmer’s son is undoubtedly one of the great theoretical physicists of history not only for his numerous scientific contributions but also for his dedication and effort in pursuit of the progress of physics and its teaching. In this last field, the fact that he was responsible for the physicians for a long time received an appropriate training in physics,, and that even after being retired at the age of seventy of from his post at Leyden University, he continued to teach until a few weeks before his death.

Lorentz was the first to use the term electron, although initially to designate elementary particles, introducing the atomistic theories in Maxwell’s theory and creating models Which would explain the interaction between radiation and matter, convinced that the latter had an atomic structure. As a result of these works, he framed Maxwell’s theory in a microscopic theory of electromagnetism considering the existing fields within matter in the void spaces between particles. All this led to what would be one of the greatest successes of his career as a theoretical physicist, the exact prediction of the normal Zeeman effect by which he received the Nobel Prize in Physics in 1902 along with Pieter Zeeman, ie by the effect of a field Magnetic uniform over spectral lines. It is curious that the normal Zeeman effect described by Lorentz is the less usual, having to frame his study within the quantum theories of radiation and that by coincidence coincides in its results with those obtained classically by Lorentz.

Undoubtedly the name of Lorentz is familiar to us above all by the Lorentz-Einstein transformation of application in special relativity when changing reference system. To explain the negative result of the Michelson-Morley experiment Lorentz adhered to Fitzgerald’s hypothesis that every moving body in the ether would undergo a longitudinal contraction. Lorentz introduced the idea of ​​local time as mathematical artifice to work with this contraction resulting from the internal tensions produced by the movement of the body in the ether. This local time as mathematical artifice would be endowed by Einstein shortly after a clear physical sense by abandoning the concept of Newtonian absolute time. Lorentz was always a classic physicist maintaining his reserves towards the ideas of Einstein but doing a fundamental work in the development of the same ones. The classical idea of ​​physics was more clearly seen with the advent of quantum theory, resisting admitting the death of determinism and the introduction of new concepts such as the quantization of energy or the fact that the position and momentum of a Particles became blurred concepts. Lorentz died in 1927, the year in which Schrödinger showed the world his equation and the concept of wave function burst in with all its force.

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