Researchers plan to look for more radio bridges, but do not expect such research will get underway until the next generation LoFar goes online—called the Square Kilometer Array (2024), it will represent not only the largest telescope in the world, but a means for taking a much closer look at filaments and possibly other magnetic fields stretching across vast areas of space.
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The Sloan Digital Sky Survey III (SDSS-III) has released the largest-ever three-dimensional map of massive galaxies and distant black holes, which will help astronomers explain the mysterious "dark matter" and "dark energy" that scientists know makes up 96 percent of the Universe.
With the new release of data, SDSS-III has begun to expand its earlier sky image into a full three-dimensional map. Data Release 9 (DR9) makes available the first third of the galaxy map that this six-year project will create.
The new data in DR9 are not only helping us understand the distant Universe, but also our own cosmic backyard, the Milky Way galaxy. DR9 includes better estimates for the chemical compositions of more than half a million stars in our own galaxy.
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Science is not just a subject to study; it is a way of living and improving mankind, without destroying nature.
It all started with the Big Bang, around 13.7 billion years ago. The Milky Way was formed around 13.2 billion years ago. The Sun and its family were born roughly 4.6 billion years ago.
Out of the eight planets and their satellites in the Solar System, only our planet Earth was blessed with life. Bacteria and other micro-organisms were one of the first forms of life that appeared on the earth, approximately 3.5 billion years ago. These micro-organisms developed into autotrophic plants and into fishes that came out of water and were transformed into reptiles and other creatures. Eventually, apes transformed into intelligent human beings through a long and complex process of evolution.
The primitive humans who used all four of their limbs for locomotion, stood up on their hind legs, and started using their arms to discover the amazing world around them.
In the Stone Age, the early humans learnt to make useful tools with stones and rocks, which were later developed into weapons, utensils, brushes etc. Humans learnt to make weapons by rubbing rocks against rocks, and small sparks lighted up fire, which enabled them to cook food, scare animals and keep themselves warm. By observing the rolling of a log of wood down a slope, humans understood the importance of the wheel in everyday life. Ashamed of being naked, they started covering their body using barks and animal skin.
They discovered and recognized patterns which helped them to chart the night sky as a calendar by identifying constellations and thus, the different seasons.
Previously, all calamities were explained using supernatural powers by the philosophers. Eventually, this power was classified into good and evil power. Each civilization expressed different opinions on these supernatural powers, thus inventing the concept of religion.
They discovered that plants grow when seeds germinate in the soil. So they now overcame the difficulty of shifting themselves for food. They started building houses that could withstand natural calamities. Eventually, humans started understanding the world better, and discovered things that would make their life comfortable. So, they started settling in civilizations and, staying and growing crops to obtain food for a living.
Every civilization contributed something or the other for the development of the human race. The Chinese Civilization invented paper and discovered silk which was kept secret for more than thousand years. The Egyptian Civilization gave their imagination wings to make the pyramids, one of the most splendid forms of architecture we have ever seen, by pushing up heavy bricks on an inclined plane. The system of counting completely changed when the Indian Mathematicians discovered 'zero', thus adding a hundred thousand digits to the number system.
The scientists came up with ideas like the Earth was in the middle of the solar system and all celestial bodies orbited the Earth. This thought was proved wrong by Nicolas Copernicus, and further established by Galileo Galilei who, peering through his telescope and observing the movements of the planets and satellites, changed the earlier notions.
ORIGINAL AUTHOR: Kwanit Gangopadhyay
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Synchrotron electrons typically travel at 99.99999 percent of the speed of light, and the secret behind their success lies with the time-dilation factor, which is as high as several thousand. This enormously boosts the frequency of the radiation as observed in the reference frame of the laboratory(at65c)
Synchrotron X-rays are used to great effect to elucidate the atomic structure of complicated materials, such as glasses, or large biological molecules(at68)
Synchrotron lithography has been used to make micromachines less than millimeter in size(at68)
We call this phenomenon a spontaneous symmetry breaking because nothing breaks the symmetry in the equations of the theory; the symmetry breaking appears spontaneously in the various solutions of these equations(dft195)
The value of the field that breaks the symmetry is commonly called its vacuum value, because the field takes this value in the vacuum, far from the affluence of any particles(dft196)
All the particles of the standard model get their masses from the breaking of the symmetry between the weak and electromagnetic forces(dft198)
This interplay between symmetry and renormalization, found over and over again, is one of the great mysteries of physics. These powerful symmetries are the reason why the superstring, which has the largest set of symmetries ever found in physics, has such wondrous properties(be59)
Nature actually demands symmetry from the start as an ironclad criterion for an acceptable merger of relativity and quantum mechanics. This is not obvious from the start. Previously, physicists believed that they could write down many possible self-consistent theories of the universe that were relativistic and obeyed quantum mechanics. Now, to our surprise, we are finding that perhaps the conditions for the elimination of divergences and anomalies are so stringent that only one theory is allowed(be100)
A beach ball is the simplest example of an object with O(N) symmetry. No matter at what angle the beach ball is rotated, the ball rotates back into itself. We say that this ball has 0(3) symmetry 0 stands for "othogonal," and 3 stands for the three dimensions of space)(be103)
Lie also discovered a set of symmetries called SU(N), which rotate complex numbers. The simplest example is U(1), which is the symmetry underlying Maxwell's equations (the "1" stands for the fact that there is only one photon). The next simplest is SU(2), which can rotate the proton and the neutron. SU stands for special unitary(be103)
The superstring theory works so well because it has two sets of powerful symmetries, conformal symmetry and supersymmetry(be110)
For the first time, a symmetry was created that could rotate a bosonic object into a fermionic object(be115)
According to superstrings, the universe originally existed in ten dimensions, not the four today. However, because the universe was unstable in ten dimensions, it 'cracked' into two pieces. With a small, four-dimensional universe peeling off from the rest of the universe(be12)
The superstring theory resembles the quantum field theory because it is based on elementary units of matter. Instead of point particles, however, the superstring theory is based on strings that interact by breaking and reforming via Feynman-like diagrams. But the significant advantage that superstrings have over the quantum field theory is that renormalization is not required(be82)
The great advantage, however, that the superstring theory has over the S-matrix theory is that it is possible to calculate with the superstring theory and eventually get numbers for the S-matrix. (By contrast, the S-Matrix theory is exceedingly difficult to calculate with and extract usable numbers.)(be82)
Nambu's idea was to assume that the hadron consisted of a vibrating string, with each mode of vibration corresponding to a separate Particle. (The superstring theory would not violate relativity because vibrations along the string could travel only less than or at the speed of light.)(be88)
Because each mode of the string represents a particle, understanding how strings collide allows us to calculate the S-matrix of ordinary particle interactions(be88)
Historically, the Mobius strip and the Klein bottle were little more than geometric curiosities, with no practical applications. To a string physicist, however, both appear as part of the Feynman diagram containing loops and are essential for the cancellation of divergences(be92)
The lowest vibration of the closed string corresponded to the graviton and the lowest vibration of the open string corresponded to the photon(be93)
The super-string theory was considered too symmetrical to be realistic(be95)
The superstring theory solves the problem of the proliferating quarks by postulating a single entity- the string- as the fundamental unit of matter with a symmetry E(8) x E(8)(be110)
The other six dimensions, although they are all around us, are too small to be observed(be142)
At present, superstring theorists are unable to calculate mathematically the precise mechanism by which a ten-dimensional universe can rupture into a four-dimensional one. The mathematics involved is beyond the capabilities of most physicists, because the problem involves a complicated quantum mechanical effect. However, the problem is well-defined mathematically, and hence it is only a matter of time before it is solved. Once the dynamics of how a ten-dimensional universe can crack into a four-dimensional one are understood, we should be able to calculate the energy stored in the original ten-dimensional universe. If the energy of the ten-dimensional universe turns out to be zero, then this would tend to support the "everything from nothing" theory(be190)
The superstring theory provides an answer to Dirac's objections because it requires no renormalization. All the Richard Feynman loop diagrams, physicists believe, are finite due to the enormous set of symmetries inherent in the theory(be194)
Putting together relativity and quantum mechanics yields so many divergences, anomalies, tachyons, and the like that only one iron-clad solution is probably possible(be195)
Originally, Michael Green and John Schwarz proposed a superstring based on the Lie Group 0(32), which contained both open and closed strings. However, although the 0(32) superstring did not have anomalies, the theory had difficulty explaining the experimental features of the known elementary particles. A rival superstring was soon proposed by the Princeton group, based on the Lie group E(8) x E(8), which contained only closed strings and did not have this experimental problem. Hence, the Princeton superstring, often called the "heterotic" string, is experimentally preferred over the 0(32) strings. Technically speaking, when physicists now refer to the superstring, they actually mean the heterotic superstring(be207)
The goal is to show that the original ten-dimensional space-time was unstable and "tunneled" via quantum mechanics into a more stable configuration given by the Calabi-Yau manifold of six dimensions and the usual Minkowski manifold of four dimensions. (It also has been conjectured that the topological structure of these Calabi-Yau spaces eventually will solve the problem of why there are at least three families of leptons and quarks.)(be208)
According to Feynman's rule, if we can't distinguish which path the photon took after the beam-splitter, we must assign a probability amplitude to each possibility. To capture the essential difference between the quantum description of a photon at a beam-splitter and a classical coin-toss, we say that the photon is in a superposition state after the beam-splitter(fp137)
Under certain circumstances the shrinkage becomes a catastrophic implosion, taking only a fraction of a second for the core to achieve nuclear densities. The implosion releases enormous gravitational energy, much of which is transported outwards by neutrinos. Although ordinary stars are transparent to neutrinos, the highly compact core of the star is so dense that there is an appreciable impedance exerted on the outgoing neutrinos. It is believed that the pressure exerted by the flood of neutrinos can blast away the outer envelope of the star into space(au66)
Supergravity became the first nontrivial extension of Albert Einstein's equations in sixty years(be96)
Supergravity (although just a small part of the superstring) emerges when we take the length of the string to be zero, that is, a point(be118)
The smallest Lie Group that can accommodate all particles is SU(5). However, the largest Lie group that could fit into supergravity is 0(8), which is too small to include all the quarks and leptons in a true GUT theory. The largest supergravity cannot accommodate both quarks and leptons simultaneously(be119)
Supergravity theory emerges from the superstring theory if we use the smallest closed superstring(be119)
Condensed matter physicists will doubtless eventually solve the problem of high-temperature superconductivity without any direct help from elementary particle physicists, and, when elementary particle physicists understand the origin of mass, it will very likely be without direct inputs from condensed matter physics(dft59)
Schrieffer had been led to some of his own work on superconductivity from his experience with meson theories of elementary particle physics(dft289)
A superconductor is in essence nothing but a piece of matter in which electromagnetic gauge invariance is broken(dft309)
Liquid oceans have existed on Earth for the greater part of the history of the solar system, implying rather narrow constraints on the temperature and luminosity variability of the sun(au54)
Dyson makes the reasonable assumption that a being's objective experience of the passage of time depends on the rate at which the being processes information: the faster the processing mechanism used, the more thoughts and perceptions the being has per unit time, and the faster time appears to pass(ltm110)
The strong force does not obey an inverse square law(au13)
The strong force acts only between nearest-neighbor nuclear particles. In contrast the electric force operates between all the protons in the nuclei(au68)
If the strong nuclear force were somewhat weaker then there would fewer stable chemical elements(au69)
It is probable that if the strong coupling constant g sub s were, say, half its observed value, then nuclei such as iron, or even carbon, would be unlikely to survive for long(au69b)
The fact that Kaon took trillions of times longer to decay than to be produced was very strange- so strange, in fact, that the scientists involved in the discovery bestowed upon the kaon a new quality which they called "strangeness"(at210)
The steady state theory posits the universe is infinite both in space and time and constantly generates new matter through some still unknown mechanism (ES107)
To introduce statistical reasoning into mechanics, the most exact of sciences, was an anathema to many of Boltzmann's contemporaries(sm6)
The physics of the nineteenth century was largely driven by the need to understand what restrictions physics placed on the ability of an engine to process energy(sm152)
Stars made of helium would suffer much shorter lives before exploding or burning out(au65)
Large, massive clouds will not readily form stars. However, if the cloud is cool enough to be unionized, cooling is much more efficient, and stars will form(au75)
When the frequency of the quantum wave associated with the incoming helium nucleus matches an internal vibration frequency of the composite system, the nuclear cross-section for capture of the third helium nucleus rises very sharply. By chance, the thermal energy of the nuclear constituents in a typical star lies almost exactly at the location of a resonance in C12. This happy accident ensures the efficient production of carbon inside stars(au117)
It has nineteen arbitrary parameters, including the mass of the leptons, the mass of the w and z particles, the relative strength of strong and weak interactions, and so on. (The standard model does not determine the value of these nineteen numbers. They are inserted ad hoc in the model, without justification, and are fixed by carefully measuring the properties of these particles.)(be76)