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42) Republic Day 2021: Parade right time to security arrangements traffic restrictions to Delhi Metro providers - All you need to know

India Republic Day -- Republic Day 2021 Parade Plan Chief Guest Security Bouquets: The parade normally perceives thousands of people and foreign dignitaries invited to see the parade. Nevertheless the number of guests and participants has been restricted due to the coronavirus pandemic this time. Republic Day time 2021 Parade Timings Main Guest Delhi Metro Services : India will celebrate the 72nd Republic Day in January 26. This day is marked to celebrate the day on which the Constitution involving India came into being in 1950. On this day the Republic Day parade takes place scaled-down the military might as well as the rich cultural heritage on the country. The parade typically sees thousands of people and unknown dignitaries invited to see the celebration. However the number of guests along with attendees has been restricted as a result of coronavirus pandemic this time. The 2010 season there will be no chief visitor or foreign dignitaries in Republic Day. The number of viewers ...
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Solar wind

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The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona. This plasma mostly consists of electrons, protons and alpha particles with kinetic energy between 0.5 and 10 keV . The composition of the solar wind plasma also includes a mixture of materials found in the solar plasma: trace amounts of heavy ions and atomic nuclei C, N, O, Ne, Mg, Si, S, and Fe. There are also rarer traces of some other nuclei and isotopes such as P, Ti, Cr, Ni, Fe 54 and 56, and Ni 58,60,62. Embedded within the solar-wind plasma is the interplanetary magnetic field. The solar wind varies in density, temperature and speed over time and over solar latitude and longitude. Its particles can escape the Sun's gravity because of their high energy resulting from the high temperature of the corona, which in turn is a result of the coronal magnetic field. At a distance of more than a few solar radii from the Sun, the solar wind reaches speeds of 250–750 km/s...
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History

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Observations from Earth edit The existence of particles flowing outward from the Sun to the Earth was first suggested by British astronomer Richard C. Carrington. In 1859, Carrington and Richard Hodgson independently made the first observations of what would later be called a solar flare. This is a sudden, localised increase in brightness on the solar disc, which is now known to often occur in conjunction with an episodic ejection of material and magnetic flux from the Sun's atmosphere, known as a coronal mass ejection. The following day, a powerful geomagnetic storm was observed, and Carrington suspected that there might be a connection; the geomagnetic storm is now attributed to the arrival of the coronal mass ejection in near-Earth space and its subsequent interaction with the Earth's magnetosphere. Irish academic George FitzGerald later suggested that matter was being regularly accelerated away from the Sun, reaching the Earth after several days. In 1910, British astrophysi...
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Acceleration

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While early models of the solar wind relied primarily on thermal energy to accelerate the material, by the 1960s it was clear that thermal acceleration alone cannot account for the high speed of solar wind. An additional unknown acceleration mechanism is required and likely relates to magnetic fields in the solar atmosphere. The Sun's corona, or extended outer layer, is a region of plasma that is heated to over a megakelvin. As a result of thermal collisions, the particles within the inner corona have a range and distribution of speeds described by a Maxwellian distribution. The mean velocity of these particles is about 145 km/s , which is well below the solar escape velocity of 618 km/s . However, a few of the particles achieve energies sufficient to reach the terminal velocity of 400 km/s , which allows them to feed the solar wind. At the same temperature, electrons, due to their much smaller mass, reach escape velocity and build up an electric field that further accelerates ions...
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Properties and structure

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Fast and slow solar wind edit The solar wind is observed to exist in two fundamental states, termed the slow solar wind and the fast solar wind, though their differences extend well beyond their speeds. In near-Earth space, the slow solar wind is observed to have a velocity of 300–500 km/s , a temperature of ~100 MK and a composition that is a close match to the corona. By contrast, the fast solar wind has a typical velocity of 750 km/s , a temperature of 800 MK and it nearly matches the composition of the Sun's photosphere. The slow solar wind is twice as dense and more variable in nature than the fast solar wind. The slow solar wind appears to originate from a region around the Sun's equatorial belt that is known as the "streamer belt", where coronal streamers are produced by magnetic flux open to the heliosphere draping over closed magnetic loops. The exact coronal structures involved in slow solar wind formation and the method by which the material is released is ...
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Solar System effects

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Over the Sun's lifetime, the interaction of its surface layers with the escaping solar wind has significantly decreased its surface rotation rate. The wind is considered responsible for comets' tails, along with the Sun's radiation. The solar wind contributes to fluctuations in celestial radio waves observed on the Earth, through an effect called interplanetary scintillation. Magnetospheres edit Where the solar wind intersects with a planet that has a well-developed magnetic field (such as Earth, Jupiter or Saturn), the particles are deflected by the Lorentz force. This region, known as the magnetosphere, causes the particles to travel around the planet rather than bombarding the atmosphere or surface. The magnetosphere is roughly shaped like a hemisphere on the side facing the Sun, then is drawn out in a long wake on the opposite side. The boundary of this region is called the magnetopause, and some of the particles are able to penetrate the magnetosphere through this regi...
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Outer limits

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The solar wind "blows a bubble" in the interstellar medium (the rarefied hydrogen and helium gas that permeates the galaxy). The point where the solar wind's strength is no longer great enough to push back the interstellar medium is known as the heliopause and is often considered to be the outer border of the Solar System. The distance to the heliopause is not precisely known and probably depends on the current velocity of the solar wind and the local density of the interstellar medium, but it is far outside Pluto's orbit. Scientists hope to gain perspective on the heliopause from data acquired through the Interstellar Boundary Explorer (IBEX) mission, launched in October 2008. The end of the heliosphere is noted as one of the ways defining the extent of the Solar System, along with the Kuiper Belt, and finally the radius at which of the Sun's gravitational influence is matched by other stars. The maximum extent of that influence has been estimated at between 50,0...
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