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Mössbauer effect

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Recoilless emission and recoilless absorption of gamma photons is called Mossbauer effect. It provides us a technique for producing and studying gamma rays whose energies are extremely well defined. Mossbauer effect was discovered by Rudolf Mossbauer in 1958. This effect is applied in the experimental field by the name Mossbauer spectroscopy. Let us first understand why a  nuclear transitions  occurs. After a radioactive nucleus undergoes decay (alpha decay, beta decay, k-capture) it many times reaches to the daughter nuclei state but contains too much energy to be in a final stable state. Unlike our electrons orbiting the nucleus, the nucleus itself doesn’t really have such orbits which are easy to visualize. So, let us just imagine it having a particular quantized energy. Now, to be in a stable ground state it must lose this extra energy. It does this by emitting gamma radiation of that energy. This is the process of nuclear transition, where the nucleus transitions from one
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Lenses

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Lenses are those circular objects which looks like a cat's eye slit when viewed from the sides. We know that there are two kinds of spherical mirrors, concave mirror (which converges light at the focus) and convex mirror (which diverges light). Similarly, in case of lenses there are two major types concave and convex (other types are plano-concave, biconcave and convexo-concave and vice-versa). In case of lenses, convex lens converges light rays whereas concave lenses diverges light rays. In mirrors we polish and silver a surface so as to reflect light coming from an object but lenses require polishing of two spherical surfaces accurately so as to refract light from the object. We know that reflection means bouncing back of light from a shiny (mostly), polished surface. What is this refraction? Refraction means bending of light rays. But light travels in a straight line. What causes it to bend? The answer is change of density of medium. But it doesn't bend just anyho
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CZTI detects a gamma ray burst!!

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CZTI was very lucky as on its first day Swift satellite had detected a gamma ray burst(GRB) named GRB 151006A. The scientists at ISRO were eager to know whether CZTI was operational at that time(i.e., outside SAA) & if the GRB was in a favourable condition to be observed. The calculation by the scientists at ISRO showed that the burst was detected 60.7° away from the direction where CZTI was presently pointing at. At this angle CZTI is sensitive to GRBs at energies greater than about 60 keV. The group of young scientists at ISRO delved into the sea of vast data to extract the precious information from GRB 151006A. (Statistics available here .)  We have the Swift and the Fermi satellites observing lots of GRBs, so what if CZTI detects one more?  The Swift satellite, as the name says, is swift at pointing a GRBs but is unable to observe those above 150 keV and fix its spectral parameter for GRBs with hard spectrum. On the other hand, Fermi satellite is sensitive to high energy e
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Illusion created while standing in front of the mirror.

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I was recently faced by this confusing question, why do mirrors reverse left and right but not up and down? Interesting isn't it? but actually it is framed wrong because the mirrors do not reverse anything they just reflect back whatever is pointed to them. Let's take the example of the image in this post. The baby has raised its one arm. If the mirror would have reversed left and right side then the arm other than this would have been seen as raised. But it doesn't happen that way because the function of the mirror is to reflect not to reverse . Now let's make it a bit simpler. Suppose you and your friend are holding a blue paper in your right hands. If your friend would be holding it in the right hand while standing in front of you then it is said that your friend has reversed the direction in which you are holding the paper. But instead of your friend, a mirror is kept in front of you then you would be seen to be holding the paper in the same direction because
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Happy Darwin Day

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On 12th February it was Darwin's Birthday normally known as Darwin Day. We all know about the contribution of Darwin to biology. We need to thank the Darwin children for the survival of the original manuscript. Darwin was actually planned to throw away the original manuscript of " On the Origin of Species".  Assumptions are that Francis Darwin drew this famous drawing of "The Battle of the Fruit and Vegetable Soldiers" who later became a naturalist like his father.  The Appendix has an amazing article on this topic. The artistry show clear evidence for Darwin's family to be nature observers. As said in The Appendix, we really owe this safe treasury of the greatest theory to the one of the ten children of Charles Darwin. Scientists and great thinkers are often viewed as serious personnel, working in isolation over the problems of the universe but we often forget that they too are human like us and they also did have a epic family life. AS A TRIBUT
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Welcome to Crash Course astronomy.

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Crash Course series has a new surprise for us. Not alone but along with astronomer Phil Plait. CrashCourse is a YouTube channel which produces various videos regarding topics like ecology, history and biology. Hank Greene hosts science topics and John Greene hosts mostly humanitarian topics. And now Phil Plait will be teaching us astronomy through crash course astronomy series available on YouTube which will be premiering on 15 Jan. Phil Plait is said to cover the basic topics like planets, naked eye sky viewing, eclipses, universe, etc. Happy learning! 
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