This morning, framed in discussions of the cycle Appointment With Science, Professor Gabriela Barenboim has given us a lecture entitled The Dark Side Of The Universe, from which I will try make a short summary so we can all enjoy it. So, without further delay.
Dark Side Of The Universe by Gabriela Barenboim
To begin, we started, where it usually starts (^_^) What we see when we look at the sky? We can see stars if you look hard enough, we can see that are grouped in a structure which we call galaxy, our galaxy, the Milky Way.
Beremboim Professor has now to comment on the life of Edwin Hubble, who considered the Father of Cosmology: not very good student law degree, later Professor, PhD in Physics and then finally, the discovery that there is one galaxy in the universe. In fact, he finds many galaxies, and even more: it measures your speed, and discover that the universe is expanding and also the speed of the galaxies are fit to call "Hubble's Law" in which the rate is proportional to the distance to the galaxy.
But these ideas of an expanding universe do not seem to be accepted as well by the scientific community, but the case is qeu if they were, and to understand, we need to discuss what led to the revolution of Relativity. En este momento, pasamos a comentar las Leyes de Maxwell y sus diferencias con las Transformaciones de Galileo, si la una era correcta, la otra no, y viceversa. En principio, se consideró que eran las Leyes de Maxwell las que necesitarían una corrección, hasta que llegó Einstein con la Teoría de la Relatividad y postuló que en realidad lo que estaba mal eran los 200 años de mecánica que se habían hecho hasta entonces. Pero ahora tenemos que demostrar que la Teoría de la Relatividad es correcta, para ello, podemos utilizar el resultado de que la propia luz sería desviada por el paso cercano a una gran masa. Para ello, necesitamos una gran masa: el Sol, y la luz de una estrella distante, y que pase al lado del sol, and that the sun does not bother the measures: we also need a total solar eclipse, of course, it was found that the relativity worked.
Now, we can apply the theory of relativity to the entire known universe, with two outcomes: Either the universe is expanding or shrinking. And as mentioned a little earlier, Hubble proved that the universe is expanding. This has interesting consequences, but first let's make a distinction between radiation and matter. We say that the first has a rate comparable to that of light, and the second much lower. Now, with our expanding universe model, we can see that radiation should be "diluted", which is known as redshifted making its wavelength is longer.
With these data, we try to predict what will happen to the universe in the future: will expand, and what happened in the past: it contracts. And besides, we can try to estimate the age of the universe: about 14 billion (14 billion) years.
At this point, we turn to discuss the composition (known at that time) of the universe. On the one hand we have fermions, with which we can build things that occupy space, and on the other bosons, with which we can collect things and no space. Both types of particles form what is called standard model of particle.
But ... How do I know it's all there is? It is known that there is more matter must interact gravitationally, so we can make a map of the gravitational field. To this end, calls can use gravitational lensing: mass concentrations at several galaxies, near which passes the light of a galaxy that is behind, and with which, by analyzing the images generated in the galaxy can deduce the mass distribution, concluding that there is a large amount of mass in stars and galaxies we see, but there is a uniform distribution of mass below of which we know nothing: dark matter. Do you really know nothing? No, already had obtained information about their existence when Vera Rubin, considered by Prof. Barenboim as the first lady of cosmology, studied about the speed of rotation of galaxies and discovering that there should be more mass than actually see.
But to measure this dark matter, we must separate from matter 'normal'. To do this, we can monitor the sky waiting for a collision between large clusters of galaxies, where dark matter comes from the opposite side without interacting with anything, and stuff 'normal' interacts each other, so that lags behind dark matter, so they are separated.
Using the Chandra telescope, found the event and confirmed the existence of dark matter. But ... Is there anything else?
Now our challenge is to weigh the universe, so we must measure the rate of expansion or deceleration of the universe. For this we need a standard distance, from which we may offer the Supernovae 1A standard candles in astrophysics at what distance can be estimated with precision. With all this, we reach the universe is expanding ... rapidly.
There must be something to neutralize the effect of gravity, a sort of negative gravity or repulsive force. To explain this we suggest the existence of something we call dark energy, which must have the following characteristics: still exists even when empty, is uniformly distributed in the universe, has a constant density, and is invisible. And by count, we find that at present, dark energy constitutes about 70% of the universe, dark matter 25% and 5% ordinary matter remaining.
Again, we try to make predictions about future and the past of the universe: in the past, the dark energy density was much lower, and in the future will be much higher.
Finally, we can summarize what is currently cosmology. So far, we have Einstein's general relativity, the Standard Model of Particles and an inventory of the components of the universe. We still have to link quantum mechanics with relativity, know what dark matter and know what dark energy. And here we can make watching the universe with probes like Planck and Fermi, and interrogating the universe with experiments like the LHC.
And, as recent details, Professor Barenboim tells us that "The Dark Side of the force is the interesting" We plant a picture of Darth Vader and says that of "May the force be with you" (^_^) I hope you enjoyed the summary If something needs to be clarified, either because they do not understand or because I have expressed avisáis wrong and corrects me when I can.
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