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Alien Life - Where are our eyes?

Life outside Earth We have been thinking of life outside earth since time immemorial. And when it comes to the scientific search of extraterrestrial life, what and where are we searching for? The primary question - what , is thought worthy.  We assume that the Life outside Earth is like the Life on Earth. We assume the life to be water-based and to share many such similarities. Why so? Life outside could be of any form. It really need not be water based. It really need not have the needs of the terrestrial life, say, oxygen. But, it is easier to look for life with this assumption, for, as the old joke goes, the old man who lost his keys at night will search for it under the streetlights. So, although we know that life on Earth could not be representative of life elsewhere, we take up the assumption while we scout for extraterrestrial life. A similar approach is also usually taken while we decide where to hunt for life. We look for Sun-like stars and Earth-like orbits and temperatures,
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The Cosmic Web

  Order from Chaos - The Cosmic Web Imagining the universe we have known about would be a picture of innumerous galaxies sprinkled randomly all around like air bubbles suspended in a gel. Chaos . That one word would describe it. However, as we zoom out, in reality, we conceive order from chaos; we would observe that all those galaxies which we envisioned to be spread out randomly are actually existing together along paths of gases. The image is exactly like motor vehicles moving through tarred roads alone, avoiding the land amidst the roads - galaxies are only present along the filaments and these filaments are linked together to form a structure like a spider’s web and we call it the cosmic web, which is a term coined by Richard Bond in 1996 to describe a tangled structure of clumps and filaments naturally formed by dark matter left to experience the pull of gravity. The area enclosed between the roads are analogous to dark matter present as voids among the cosmic web and accounts to
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What's smaller than the smallest - An Introduction

 People have thought about the existence of particles smaller than the smallest sensible particles of matter from time immemorial. Moreover, a similar philosophy of ' anu ' is mentioned in the ancient Indian texts. However, this suspicion had no scientific grounds until one or two centuries ago. Now, we know that matter is composed of atoms, atoms of nucleons and electrons, and nucleons of quarks. The concept of an atom was first scientifically proposed by John Dalton, which was further developed by Ernest Rutherford and Neils Bohr, although J J Thomson was the first to propose a model after Dalton. While Thomson presented a model of atom in which the electrons are distributed in a positive space as if seeds in a watermelon or plums in a pudding, Rutherford's famous gold foil experiment proved that most of the space inside an atom is empty and that the positive charge is concentrated in a centre called nucleus, and thus proved Thomson to be incorrect. An interesting thing w
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Habitable Zone around a Black Hole

Black Holes are always considered as reapers of life. So, here's a twist! LIFE AROUND A BLACK HOLE! Black Hole A black hole is a point in space-time fabric with extremely high density. The gravitational pull of a black hole isa so high that not even light can  escape its gravity.  AGN - Active Galactic Nucleus Simply, the nucleus or centre of an active galaxy.  This galaxy would be having a blacl hole at its centre. Around the black hole would be a disc of stars and gas, spiraling into the black hole, called the accretion disk. Let us see the possibility of life in this accretion disk, powered by the black hole.  Life Around It AGN emit different radiations. UV rays are also emitted. UV rays have the potential to power reactions for prebiotic chemistry. i.e, if prebiotic elements are available,  which are commonly available in and around a star, the UV rays can mediate the reactions between them,  synthesizing the simple biomolecular building blocks. Thus, the ori
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Why are Black Holes black? (Gravitational Red Shift)

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Why are Black Holes black? We all know: black holes are black. No light escapes a black hole. But, why?  We come across the answer for this while studying gravitational red shift. Gravitational Red Shift Gravitational red shift is similar to the concept of Doppler red shift, but different. Doppler red shift is a change (lowering) in frequency of a wave due to its velocity. But, gravitational red shift is the lowering of frequency of a wave due to gravitational force in the space-time fabric. The derivation that explains this shift happens o be simple, but we shall leave that for now. At the end of the derivation we conclude that the relative frequency change of a wave (due to gravitational force) equals to GM/c 2 R; where G and c are our familiar constants - Newton's 'G' and the light's 'c', and M and R are the mass and radius of the star respectively. The star here could be the star of any phase - a main sequence star, a super giant or even a
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Einstein's Biggest Blunder! Einstein, Relativity and The Cosmological Constant

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ALBERT EINSTEIN'S BIGGEST BLUNDER Even the great physicist Albert Einstein made an utter foolishness? (He did!) But, the biggest quality of a scientist is to admit his mistakes, right? Pic credits: Ugur Peker, Unsplash THE COSMOLOGICAL CONSTANT When you hear the term, what's your primary guess on that? It's something related to cosmology? Okay, it's something regarding cosmology. It's a constant? Well, again yes, it is a constant; an Albert Einstein Constant. It comes in Einstein law? Uh, what do you mean? Einstein Law? What is that? So, let's get to it. THE THEORY OF RELATIVITY What is the theory of relativity? Everything is relative to one another. There is this Special Theory of Relativity which is regarding the elementary particles and their interactions and the General Theory of Relativity which is regarding the laws of gravitation and the other forces of the universe. The postulates of the Special Theory are: 1.The laws of physic
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What's wrong with Hubble's Law? The Non-Constant Constant!!?

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Hubble's Law - sounds interesting and elegant. But, then what's wrong with it? Well, that's not a law. THE HUBBLE'S LAW " All objects move from each other and the apparent relative velocity is proportional to distance . "   That is the Hubble's Law. Mathematically, Ｖ=ℍ₀ D  This  ℍ₀ is the Hubble's Constant - which is in fact, a non-constant constant. The value changes with time, and the precise value had been a matter of debate for nearly one century. Currently, as per March 2019 the Planck Mission shows the value to be 74.03±1.42% using Hubble Space Telescope observations. The Hubble's Law serves a strong evidence for the big bang theory. Don't know much about the BIG-B ? We'll post an update soon. Hubble and his Assumptions The Hubble's Law serves a basis for most of the modern cosmological concepts and views. But, even this foundational law makes many philosophical assumptions, especially on the unif
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