## Einstein’s Amazing Theory of Gravity

Earlier this week I attended a talk by Sir Roger Penrose FRS in celebration of the 100th anniversary of the publication of Einstein´s General Theory of Relativity. The talk was entitled Einstein’s Amazing Theory of Gravity and it was sponsored by the London Mathematical Society (of which I am a proud member) and held at the Science Museum as part of the November Lates events. It also coincided with the 150th anniversary of the LMS!

Not only was the LMS and the Science Museum commemorating the centenary of the birth of Einstein’s Theory of General Relativity but other outlets were too. It may be difficult to put an actual date to Einstein’s work, but we know that on November 25th, 1915 Einstein presented the “final” form of his theory to the Prussian Academy of Sciences. You can find a full translation of the paper “The Field Equations of Gravitation” here. It is interesting to note that he refers to a couple of earlier papers in that work, but the one we are referring to presents the theory in full.

During his talk, Penrose indeed talked about Relativity and I would have preferred that he concentrated on the theory per se at a more introductory level, after all it was part of a public talk in the Science Museum. He talked about black holes and did not shy talking about conformal geometries for example (bravo!). He finished his talk by presenting some of his own work regarding eons and cyclical cosmology. You can get a flavour of what he talked about in this recording of a lecture he gave in 2010.

## Backwards and Forwards in Time

Time flies, time is money, time is a wise counsellor, time is relative, time is… very hard to define. Paraphrasing St Augustine I can say that  I know what time is if no one asks me, but if I try to explain it I simply do not know. It seems to be very natural to acknowledge the passing of time, however when we take a moment to think about its meaning, we quickly find ourselves with a few problems.
We start by arguing that time can be defined by the interval between two successive events and thus we need a ruler to measure that interval. This is indeed a quest that us humans have pursued since the dawn of civilisation; it is very easy to see how the definition of day comes about: it is the interval between two successive sunrises. Once we have this in place a lot follows effortlessly: on the one hand we can start taking smaller intervals and define hours, minutes, seconds, and on the other, it is now possible to refer to events taking place in the past, the present and even the future. The ordering of these three concepts is intuitive as time flows from the past to the future, and we even see it manifested in the objects around us. We can imagine that we go to a museum where a film installation is being shown. The film starts with a large red stain in an otherwise immaculately white carpet. The camera spans and we see some pieces of glass strangely being attracted to each other while the red stain starts to shrink. The next thing we see is a wine glass appear before our eyes and wine droplets jump into it as if by magic. It is immediately obvious that the film was played in reverse as there seems to be a natural “forward direction”. This directionality is often referred to as the arrow of time and whenever it is discussed the subject of causality arises, and even time travel.

When I mention causality I am referring to the relationship between causes and effects; in the case of the film I used as an example, the cause of the spill is shown to us as artist hits the wine glass. When the film is shown in reverse, we tangibly notice that there is something missing: the glass cannot “unbreak” out of its own accord. What does physics have to say about this? If we were to analyse the film using the laws of motion described by Newton, we would find that there is no difference between the forward and backward directions. In other words, time reversal is not prohibited anywhere in Newtonian mechanics. This means that, given a present state under specific conditions, we are therefore able to predict the future, but also retrodict the past, as there is no distinction between the two. This sounds surprising as this sort of thing does not happen in our daily lives.

Scientists have come up with their own versions of the wine glass film described above. In one case, they have taken two particles of light, known as photons, with certain energies and mashed them together; after the collision they observed a pion and a deuteron as a result of the collision. Do not be too concerned about what these two new particles are, this will not affect the discussion. When the film is reversed, it shows a pion and a deuteron colliding and producing as a result two photons. This new experiment has been realised and lo and behold the physicists observed the generation of the two photons as predicted, giving them a confirmation that the laws that govern these phenomena do not change when time is reversed. As you may have noticed, we have blatantly ignored the present, and this is because we think of it as a transitory state between the past and the future. In other words, the past is gone while the future has not arrived, and the ephemeral present expires as soon as we try thinking of it.

From this point of view, the result of these experiments seems to indicate that the arrow of time is embedded in our perception. It has been argued that the arrow of time is a psychological effect, and that this feeling that time flows mercilessly from the past to the future is all subjective. Let us take these arguments a step further, if indeed there is no difference between past and future, then there is nothing stopping us from travelling to the future (as we imminently do) or to the past (as we clearly are not). Believe it or not, but physics has something to tell us about this. I mentioned above that time reversal is allowed by Newtonian mechanics, so why can we not put together again the wine glass by time reversing the process, rather than supergluing the broken pieces? The answer is not in the realm of mechanics, but in that of thermodynamics, in other words the study of how energy converts between heat and other forms of energy. In that manner, physicists also talk about a thermodynamic arrow of time, in the sense that a given physical system invariably becomes ever more disordered, and since disorder is therefore important we quantify it with a quantity called entropy. This rule that tells us that entropy increases with time is known as the second law of thermodynamics. Following this line of thought, we are not allowed to fix our broken wine glass by running time backwards because it would imply going from a more disordered state to a more ordered one without using any extra energy, and so travelling to the past is not an easy task to achieve.
What about travelling to the future, or in the direction pointed by entropy? Well, in that case there is certainly nothing that stops us in our tracks. In fact, as I pointed out earlier on, we are already travelling to the future, and we do that at a pace of sixty minutes an hour. However, if we wanted to travel to the future at a different rate, Einstein’s theory of relativity gives us a recipe to achieve this. In the so-called special theory of relativity the world has four dimensions: the usual three space dimensions that we know and love, i.e.. length, width and height; and one dimension that is related to time. In other words, when you walk from one place to another in the gallery where the wine glass video is being shown, you automatically change your position on the time coordinate, even if you don’t notice. Einstein tells us that if we were to travel at the speed of light, time expands from the perspective of a stationary observer, whereas space contracts from the point of view of the moving person. This brings into question the notion of simultaneity, as two events that seem to happen at the same time for the stationary person, could in principle happen at different times from the point of view of the moving person. It is fascinating to compare Einstein’s efforts to unravel the secrets of simultaneity in time, with Picasso’s cubism to depict simultaneity in space. The effect of time dilation has been experimentally confirmed with very precise caesium clocks. Unfortunately, it is completely outside of human experience, because we have not yet devised a way of travelling at speeds where relativistic effects become noticeable. Even if we were to spend our entire lives in a plane that moves at supersonic speed, we would barely win a second over our contemporaries on the ground.

So, time travel as presented to us in sci-fi films is not yet possible but that has not stopped us from imagining its consequences. As for the definition of time, I am sure that there are many other things that can be said on the subject. Unfortunately, time is a merciless master, and that is all the time and space I have for now.

Dr Jesús Rogel-Salazar
(originally appeared in Artesian : Issue Three : Time : 2011)

## Listen as Albert Einstein Reads ‘The Common Language of Science’ 1941 | Open Culture

Have you ever wondered how Albert Einstein sounded? Well here you have an opportunity to find out. In the link above there is a recording of Einstein reading an essay (in English) called “The Common Language of Science”.

Enjoy!

Ada Lovelace. Painting by Margaret Sarah Carpenter (1793–1872)

Ada Augusta Byron, Countess of Lovelace, was the daughter of the poet George Gordon, Lord Byron. She studied mathematics at the University of London with Charles Babbage, whose analytical engines were the precursors of the modern computer. Today 10th of December, it would have been her 197th birthday. That is why Google created a doodle for her (see image below).

Ada Lovelace is today known as a mathematician and computer pioneer; she created the concept of an operating system. Supplementing her translation of an Italian article on Babbage’s analytical engine with an encoded algorithm she published the first computer program, albeit for a machine that would not be built until more than 150 years later as a historical project.

The Ada computer language was named after her.

## The Babbage Difference Engine – Sci-Advent – Day 3

In 1849, British inventor Charles Babbage completed designs for a difference engine, a very early mechanical computer. Due to cost and complexity the machine was never built in his lifetime and for 150 years nobody knew if the machine would have worked. In 2002, a Babbage Difference Engine based on the original plans was completed—and it actually works. The hand-cranked device has 8,000 parts, weighs 5 tons, and is 11 feet long. Two such machines now exist, one at the Science Museum in London and another at the Computer History Museum in Mountain View, California. To get a sense of the incredible intricacy of the Babbage Difference Engine, take a look at these interactive high resolution images of the Computer History Museum machine. The images, created by xRez Studio, are each composites of up to 1,350 individual photos. The studio also shot this short video of the machine in operation.

## Happy birthday Turing

Today, a 100 years ago Alan Turing was born. As a form of celebration Google has put a functioning Turing machine as their latest doodle. A Turing machine is a device that uses a tape with symbols that are manipulated according to certain rules and as you can imagine it was proposed by Turing in 1936.

## Leonhard Euler – Quantum Tunnel Podcast

Leonhard Euler (1707-1783) was Switzerland’s foremost scientist and one of the three greatest mathematicians of modern times (the other two being Gauss and

Euler was a native of Basel and a student of Johann Bernoulli at the University, but he soon outstripped his teacher. His working life was spent as a member of the Academies of Science at Berlin and St. Petersburg. He was a man of broad culture, well versed in the classical languages and literatures (he knew the Aeneid by heart), many modern languages, physiology, medicine, botany, geography, and the entire body of physical science as it was known in his time.  His personal life was as placid and uneventful as is possible for a man with 13 children.

Though he was not himself a teacher, Euler has had a deeper influence on the teaching of mathematics than any other man. This came about chiefly through his three great treatises: Introductio in Analysin Infinitorum (1748); Institutiones Calculi Differentialis (1755); and Institutiones Calculi Integralis (1768-1794). There is considerable truth in the old saying that all elementary and advanced calculus textbooks since 1748 are essentially copies of Euler or copies of copies of Euler.

He extended and perfected plane and solid analytic geometry, introduced the analytic approach to trigonometry, and was responsible for the modern treatment of the functions $log x$ and $e^x$. He created a consistent theory of logarithms of negative and imaginary numbers, and discovered that $log x$ has an infinite number of values. It was through his work that the symbols $e$, $pi$, and $i$ became common currency for all mathematicians, and it was he who linked them together in the astonishing relation $e^{pi i} + 1=0$. This is a special case of his famous formula $exp(itheta)=cos theta + i sin theta$, which connects the exponential and trigonometric functions. Among his other contributions to standard mathematical notations were $sin x, cos x$, the use of $f(x)$ for an unspecified function, and the use of $Sigma$ for summation. He was the first and greatest master of infinite series, infinite products and continued fractions, and his works are crammed with striking discoveries in these fields.

He contributed many important ideas to differential equations: the various methods of reduction of order, the notion of an integrating factor (often called an Euler multiplier), substantial parts of the theory of second order linear equations, power series solutions – all these are due to Euler. In addition he gave the first systematic discussion of the calculus of variations (founded on his basic differential equation for a minimizing curve), discovered the Eulerian integrals defining the gamma and beta functions, and introduced the Euler constant:

$gamma=lim_{nrightarrow infty}(1+frac{1}{2} +frac{1}{3}+...frac{1}{n})=0.5772...$

which is the most important special number in mathematics after $pi$ and $e$. He also worked with Fourier series, encountered the Bessel functions in his study of the vibrations of a stretched circular membrane, and applied Laplace transforms to solve differential equations – all before Fourier, Bessel, and Laplace were born. The origins of topology – one of the dominant forces in modern mathematics – lie in his solution of the Königsberg bridge problem and his formula $V - E + F=2$ connecting the numbers of vertices, edges, and faces of a simple polyhedron.

In number theory, he gave the first published proofs of both Fermat’s theorem and Fermat’s two squares theorem. He later generalized the first of these classic results by introducing the Euler $phi$ function; his proof of the second cost him 7 years of intermittent effort. In addition, he proved that every positive integer is a sum of four squares, investigated the law of quadratic reciprocity, and initiated the theory of partitions, which deals with such problems as that of determining the number of ways in which a given positive integer can be expressed as a sum of positive integers. Some of his most interesting work was connected with the sequence of prime numbers, with those integers $p>1$ those only positive divisors are 1 and $p$. His used the divergence of harmonic series $1+frac{1}{2}+frac{1}{3}+...$ to prove Euclid’s theorem that there are infinitely many primes.

The distinction between pure and applied mathematics did not exist in Euler’s day, and for him the physical universe was a convenient object that offered scope for methods of analysis. The foundations of classical mechanics had been laid down by Newton, but Euler was the principal architect. In his treatise of 1736 he was the first to explicitly introduce the concept of a mass-point or particle, and he was also the first to study the acceleration of a particle moving along any curve and to use the notion of a vector in connection with velocity and acceleration. His continued successes in mathematical physics were so numerous, and his influence was so pervasive, that most of his discoveries are not credited to him at all and are taken for granted by physicists as part of the natural order of things.

However, we do have Euler’s equation ns of motion for the rotation ‘of a rigid body, Euler’s hydrodynamical equation for the flow of an ideal incompressible fluid, Euler’s law for the bending of elastic beams, and Euler’s critical load in the theory of the buckling of columns. On several occasions the thread of his scientific thought led him to ideas his contemporaries were not ready to assimilate. For example, he foresaw the phenomenon of radiation pressure, which is crucial for the modern theory of the stability of stars, more than a century before Maxwell rediscovered it in his own work in electromagnetism.

Euler was the Shakespeare of mathematics – universal, richly detailed, and inexhaustible.

News

Bilingualism key to language survival
There are about 6000 different languages in the world, but just a handful, including English, dominate. Some mathematical models have shown how dominating languages can lead to the decline and extinction of less popular languages. However. Physicists in Span are challenging this idea. According to Jorge Mira Pérez and his colleagues at the University of Santiago de Compostela earlier models have not taken into account bilingualism which allows both languages to co-exist and evolve.
The researchers compared the results of their model to historical data for the preponderance of Spanish and Galician from the 19th century to 1975 and found that the fit is quite good. They find that both languages can survive so long each is initially spoken by enough people and both are sufficiently similar. The paper was published in the New Journal of Physics.

Periodic Table of Shapes
We are very familiar with the periodic table of elements, whose invention is attributed to Dimitri Mendeleev in 1869 and it has become ubiquitous in many a classroom. The table is a visual representation of the periodic law which states that certain properties of the elements repeat periodically when arranged by atomic number. Researchers at Imperial College London are interested in creating a periodic table of shapes which would become a very useful resource for mathematicians and theoretical physicists looking for shapes in three, four and five dimensions that cannot be broken into simpler shapes. These basic blocks are known as “Fano variaties” and for them to represent practical solutions to physical problems, researchers need to look at slices of the Fano varieties known as Calabi-Yau 3-folds which give possible shapes of the curled extra dimensions required by string theory.

Enlarging Schrödinger’s cat
Quantum mechanics tell us that a quantum object can exist in two or more states simultaneously, this is called a quantum superposition and usually it can be seen in very tiny objects. Nonetheless researchers in Austria have recently demonstrated quantum superposition in molecules composed of up to 430 atoms each.
Erwin Schrödinger proposed a thought experiment to illustrate the apparent paradoxes of quantum theory in which a cat would ne poisoned or not depending on the state of a quantum object. Since the object could be in a superposition of states, the cat would thus be dead and alive at the same time. This highlights the difference between the classical and the quantum worlds and poses the question as to how big would the objects have to be in order to perceive their quantumness.
Markus Arndt and colleagues have shown the observation of quantum effects in large molecules tailor-made for the purpose – up to 6 nanometres across and with up to 430 atoms, several times larger than molecules used in similar experiments in the past.

Female hormone holds key to male contraceptive
Contraceptive pills have been in the market for 50 years not, but are only available for women. Scientists had known that high doses of certain hormones stopped ovulation, but extracting the quantities needed for scale production was too difficult. It was not until invention of progestine by Mexican chemist Luis Miramontes and co-workers that lead to the creation of oral contraceptives.

Recently, two studies published in Nature (1, 2)  point to a breakthrough to design a new class of contraceptive pills. Researchers have shown how sperm sense progesterone, a female sex hormone, which serves as a guide to the egg. Progesterone activates a molecular channel called CatSper, which floods sperm cells with calcium. Problems with progesterone sensing could explain cases of infertility. The results could pave the route to coming up with a male contraceptive pill in the future.

## Sir Isaac Newton (Parte II) – Quantum Tunnel en Español

Puedes descargar este podcast en iTunesFeedburner.

En el episodio anterior mencionábamos que en 1669 Newton experimentó lo que podríamos llamar un año de genialidad durante el cual realizó algunos de los más notables descubrimientos en la historia de la ciencia, sin embargo no siempre estaba interesado en hacer dichos descubrimientos públicos.

Los Principia Mathematicae siempre ha sido un libro difícil de leer, puesto que esta escrito en un estilo frío y remoto, tal vez bastante apropiado para la grandeza de los temas que aborda. Además la densa cantidad de matemáticas empleada consiste casi únicamente en geometría clásica, la cual era muy poco cultivada en ese entonces, y lo es mucho menso hoy en día.

Después de la gran actividad llevada acabo en la creación de los Principia, Newton una vez más dejó de lado la ciencia. En 1696 dejó Cambridge y se trasladó a Londres para convertirse en Jefe de la Casa de Moneda. Durante el resto de su vida entró poco en la vida en sociedad pero tuvo oportunidad de disfrutar de su posición única en la cima de su fama científica. Estos cambios en sus intereses y en su ambiente no hicieron que disminuyeran sus poderes intelectuales. Por ejemplo, una tarde, al final de un arduo día de trabajo acuñando monedas escuchó acerca de el problema de la braquistrocrona propuesto por Johann Bernoulli quien lo describió como un problema para los más agudos intelectos matemáticos del mundo entero, y así Newton lo resolvió esa misma tarde antes de ir a dormir.

De gran interés para la ciencia es también su publicación de Opticks en 1704. En este libro asimiló y extendió su trabajo acerca de la luz y el color. Como apéndice agregó sus famosas Queries o Cuestiones, que son especulaciones en áreas de la ciencia que se encuentran mucho más allá del entendimiento científico en aquel entonces. Muchas de estas cuestiones tienen que ver con la preocupación constante que Newton tenía para con la química (o alquimia como se le llamaba en su tiempo). Así pues formuló varias conclusiones tentativas pero largamente consideradas, siempre fundamentadas en experimentos, acerca de la probable naturaleza de la materia. Y aunque el probar sus ideas tuvo que esperar la llegada del refinado trabajo experimental de finales del siglo XIX y principios del XX, sus ideas generales han sido corroboradas al menos en cuanto a nociones generales se refiere.

Newton ha sido siempre considerado y descrito como el estereotipo del racionalista, como la personificación de la Edad de la Razón. Tal vez sería más preciso pensar acerca de él en términos medievales – como un místico intuitivo, consagrado y solitario, para quien la ciencia y las matemáticas eran herramientas para descubrir los misterios del Universo.

Noticias

Una clave del cáncer de mama es hallada

Expertos en cáncer han identificado un gen que causa una forma particularmente agresiva de cancer de mama. El nombre que se ha dado a este oncogen is ZNF703 y se encuentra sobreactivado en uno de cada doce canceres de mama. Científicos trabajando para Cancer Research UK llevaron a cabo la investigación y mencionan que el gen era uno de los candidatos clave para el desarrollo de nuevas medicinas contra el cáncer de mama. El estudio fue publicado en la revista EMBO Molecular Medicine.

Físicos ponen en reversa al laser

Creo que la gran mayoría de nosotros está familiarizado con la luz laser y por tanto parecería un tanto extraño el pensar en un laser que absorbe un rayo brillante en vez de emitirlo. Sin embargo, científicos de la Universidad de Yale han recientemente reportado en la revista Science el desarrollo de un aparato que convierte haces laser en calor.
Cao y sus colegas utilizaron una oblea de silicón y un laser infrarojo sintonizable para sus experimentos. Lo que hacen es dividir el haz laser en dos e iluminan con él ambos lados de la oblea de silicón. La parte anterior y posterior de la oblea funcionan como espejos, mientras que el silicón en medio juega las veces del medio dentro de una cavidad laser. Al cambiar la frecuencia del laser, así como otras propiedades, los fotones son atrapados entre las superficies de la oblea. Mientras los fotones rebotan entre las superficies, el silicón los absorbe hasta que todos desaparecen y son convertidos en calor.

Oliendo vibraciones cuánticas

Una de las teorías más arraigadas acerca de la percepción de olores es que las formas de las diferentes moléculas proveen las pistas que nuestros cerebros registran como olores. Sin embargo, se ha reportado recientemente que algunas moscas de la fruta pueden distinguir entre dos moléculas con formas idénticas, lo cual nos da la primera evidencia experimental que soporta la teoría de que el sentido del olfato opera detectando vibraciones moleculares.

Efthimios Skoulakis del Alexander Fleming Biomedical Sciences Research Center en Vari, Grecia, llevó a cabo los experimentos con moscas de la fruta. El equipo inicialmente puso a las moscas en un laberinto y las dejaron escoger entre dos ramas, una contenía un químico con fragancia tal como acetophenon, un ingrediente común en perfumes, y la otra una versión deuterada. Si las moscas estuvieran detectando olores basándose en forma únicamente, entonces no podrían diferenciar entre ambas ramas. Los científicos encontraron que las moscas preferían el acetophenon ordinario.

Projecto de prese brasileña es bloqueado

En el episodio anterior reportamos la aprobación para la construcción de una controversial presa en el Amazonas, la planta hidroeléctrica de Belo Horizonte, la cual es la tercera planta de su tipo en el mundo. Los planes han sido suspendidos por un juez brasileño debido a asuntos ambientales.

El juez Ronaldo Desterro detuvo los planes de construcción puesto que no cumplian con los requerimientos ambientales debidos, asimismo, el banco nacional de desarrollo tiene prohibido financiar el proyecto. La licencia de construcción fue otorgada en Enero.

Conferencia de Comunicación de la Ciencia en Londres

La British Science Association anunció recientemente su congreso anual de dos días acerca de la comunicación de la ciencia. El evento tiene como objetivo el abordar algunos de los temas principales que enfrentan los comunicadores de la ciencia en el Reino Unido. El evento se llevará acabo los días 25 y 26 de Mayo en King’s Place, King’s Cross, en Londres. El tema principal de la conferencia será “dialogo en línea” y se exploraran usos innovativos de los medios en línea para establecer dialogo entre el público y la ciencia. El registro para la conferencia abrió el 14 de Febrero y cerrará el 13 de Mayo. Para mayor información dirijanse a la página de internet de la asociación.

## Sir Isaac Newton (Parte I) – Quantum Tunnel en Español

Puedes descargar este podcast en iTunesFeedburner.

En esta ocasión el Quantum Tunnel Podcast en Español nos habla acerca de de uno de los científicos con mayor influencia: Sir Isaac Newton. Creo que todos estamos familiarizados con su encuentro con aquella manzana y su nombre esta por siempre ligado con la gravedad, la óptica el cálculo entre otros muchos temas. Aquellos que saben dicen que Newton es considerado como uno de los más poderos intelectos que la raza humana haya conocido.

La reputación de Isaac Newton y su fama como el descubridor de la ley de gravitación es bien reconocida. Newton nació en 1642 en una familia de agricultores en la villa de Woolsthorpe en Inglaterra.

En 1665, a la edad de 23 años, un brote de plaga hizo que las universidades cerraran sus puertas, y Newton regresó a casa donde permaneció hasta 1667. Ahí, en dos años de rústica soledad, su genio creativo floreció, haciendo descubrimientos que difícilmente pueden ser sobrepasados: la serie binomial para exponentes negativos y fraccionales, el cálculo integral y diferencial, la ley de gravitación, y la resolución de la luz solar en su espectro a través de un prisma.

Newton fue siempre un hombre tímido y reservado, a tal grado que normalmente mantenía sus monumentales descubrimientos para el mismo. No tenía interés en publicar y la mayoría de sus grandes trabajos eran casi casi extirpados gracias a la persistencia de sus colegas. Sin embargo, sus habilidades fueron evidentes para su maestro Isaac Barrow, quien en 1669 renunciara a su puesto de profesor a favor de su estudiante; algo nunca antes visto. Newton se asentó en Cambridge por los siguientes 27 años.

Sus descubrimientos matemáticos nunca fueron publicados en colección, por el contrario, la mayoría fueron dados a conocer casi accidentalmente a través de conversaciones y contestaciones a preguntas hechas por correspondencia. Por ejemplo, al mismo tiempo que Newton, Leibnitz en Alemania había inventado el cálculo de manera independiente y gracias a su correspondencia con los Bernoulli y con Euler, el liderazgo en análisis pasó al continente, donde se mantuvo por los siguientes 200 años. Es interesante ver la correspondencia de Newton con Leibnitz, a través de Oldenburg en 1676 y 1677, donde Newton discute su serie binomial pero esconde en anagramas las ideas acerca del cálculo y de las ecuaciones diferenciales, mientras que Leibnitz revela abiertamente su versión del cálculo.

No se sabe mucho acerca de la vida diaria de Newton como Profesor en Cambridge, pero se puede afirmar que la óptica así como la construcción de telescopios se encontraban entre sus mayores intereses. Experimentó con muchas técnicas para pulir lentes e hizo sus propias herramientas y en 1670 construyó su primer telescopio.

En el siguiente episodio continuaremos esta fascinante historia., no se la pierdan.

Noticias

Los granjeros más pequeños

Investigadores de la Rice University en Houston., Texas reportaron en ScienceNOW el descubrimiento de lo que puede describirse como los granjeros más pequeños del mundo – una amiba que recoje bacterias, las lleva a nuevos lugares y luego las cosecha.

T.Rex vuelve a la caza

Después de mucha discussion entre paleontólogos acerca de la naturaleza depreda-dora del Tiranosaurio Rex, los últimos descubrimientos parecen poner de nueva cuenta a esta criatura en la categoria de temible cazador y no como lamentable carroñero. Investigaciones realizadas por la Zoological Society of London han dado más peso al argumento de depredador puesto que el gran número de pequeños carroñeros en el Cretacisco tardío en Norte América habrían olido los restos de animals muertos mucho más rápidamente que el Tiranosaurio, dejando a éste como única posibilidad la de cazar.

Presa en el Amazonas

Recientemente se ha dado luz verde para la construcción en Brasil de la tercera presa más grande del mundo. Situada en un sistema tributario del Río Amazonas, la planta hidroeléctrica de Belo Monte necesitará la tala de 2.3 kilometros cuadrados así como inundar como 492 kilometros cuadrados de tierra.

Controversia acerca del kilogramo

Durante una conferencia en la Royal Society en Londres llevada a cabo los dias 24 y 25 de enero, Richard Davis, ex-jefe de la división de masa en la Oficina Internacional de Pesos y Medidas en Sèvres, Francia, sugirió una forma de reconciliación para permitir la largamente planeada redefinición del kilogramo. De acuerdo a su plan, los dos tipod de experiemento que no se ponen de acuerdo serían promediados, de manera que la media sería usada para definir el nuevo estandard.

Desde 1889, el kilogramo ha sido definido como la masa de un cilindro hecho de paltino e iridio que se encuentra en una caja de seguridad en Francia. El plan es remplazar al cilindro con una definición en terminus de una constante fundamental. Los científicos han usado dos métodos para ello. Uno es usando una “balanza de Watt” donde el kilogramo es definido en terminus de la constante de Planck. El segundo método consiste en contra los átomos en una esfera de silicio cristalino. En este caso el kilogramo estaría dado por el número de Avogadro. De cualquier forma, los físicos esperan que ambos métodos puedan ser reconciliados a tiempo para la Conferencia General de Pesos y Medidas que se llevará a cabo en 2015.

El Presidente de la Royal Society contra la falta de conifianza en la ciencia

Sir Paul Nurse, el nuevo Presidente de la Royal Society ha expresado sus preocupaciones acerca de los niveles de vilificación personal de científicos y la falta de confianza contra la ciencia.

Así pues ha pedido a los científicos el abordar a los críticos que siembran dudas concernientes a sus proyectos de investigación yendo desde el cambio climático hasta la modificación genetica de semillas.

En el documental Horizon para la BBC, Sir Paul Nurse dijo: “ Los científicos tienen que salir y ser abiertos acerca de los que están haciendo… aún si pone sus reputaciones en duda. Esto es mucho muy importante como para dejarlo en manos de polemicistas y comentaristas en los medios. Los científicos tienen que estar ahí también. Tenemos una insane combinación de medios y política que distorsiona los reportes científicos y es un problema real para todos si es que la ciencia tiene un impacto propio en la sociedad”.