Hence, understanding the coronal magnetic field will lay the foundation to predict the volatile nature of the corona.Ī solar eclipse presents an opportunity to directly measure the magnetic fields emanating from the corona. These occur when magnetic energy stored in the corona becomes unstable. Occasionally, high-energy material hurtles across space referred to as coronal mass ejection or CME. This heats the corona which accelerates the solar wind. Energy flows from the corona to the photosphere in the form of waves as well as heat caused by ‘braiding’ or tangling of magnetic fields in the corona. Imagine hundreds of fireworks exploding constantly around the Sun. It is a chaotic display of solar flares igniting and radiating randomly. Upon closer examination, the corona, composed of hot plasma, is a lustrous whorl of solar activity. For instance, we have very little understanding of the magnetic field of the corona, which is believed to hold the key to unravelling the mysteries of its many solar activities.ĭr Edward DeLuca, from the Smithsonian Astrophysical Observatory (SAO), and his team of scientists have utilised this rare solar eclipse opportunity to plan and execute an experiment that will advance our knowledge of the Sun’s corona. Although scientists now understand a lot about the make-up of the Sun, there are still many fundamental questions that have eluded viable explanation. During a total eclipse, the Moon completely obscures much of the Sun’s light, revealing the innermost part of the corona – a difficult thing to observe under ordinary circumstances. This comprises plasma that extends hundreds and hundreds of kilometres into space. The Sun’s corona is simply its outer atmosphere. Having the Sun blocked out allows scientists to explore a relatively unknown aspect of the universe we live in – the Sun’s corona. In August 2017 in America, this rare phenomenon could actually be seen in person.īeyond its aesthetic appeal, a solar eclipse offers a rare opportunity for researchers to observe certain solar and atmospheric phenomena that cannot normally be seen because of the Sun’s light. One of science fiction’s greatest and most-beloved movies – 2001: A Space Odyssey – opens by showing a scene where the Sun and the Moon line up perfectly to form a solar eclipse. During the “Great American Eclipse” in 2017, that’s exactly what he did. Fortunately, solar eclipses (where the Moon and Sun perfectly overlap ‘in syzygy’) provide scientists, such as Dr Edward DeLuca at the Smithsonian Astrophysical Observatory, with an opportunity to explore this unknown phenomenon. Our knowledge of the outer atmosphere of the Sun – called its corona – is still fairly limited, due to difficulties observing this part of the Sun. During maximum solar activity there is sufficient ionization of the outer atmosphere to reduce the magnetic field to a low value even at the poles, and hence the outer atmospheric spray extends roughly equally in all directions, in accord with the appearance of the corona.How do you observe a faint light next to a very bright one? Put simply, with great difficulty. Whereas the wide spreading structureless coronal luminosity extending out from the lower latitudes is due to an accumulation of ionization which reduces the magnetic field to a low value and permits the radiation to blow the particles out to great distances. Thus the polar plumes, prominent during sun-spot minima, are regarded as owing their form to the magnetic field of the sun. By distillation along the lines of magnetic force the particles collect in the lower latitudes of the solar outer atmosphere and by their diamagnetism reduce the magnetic field approximately to zero in this region, leaving a stray field at the poles. The outer atmosphere of the sun is assumed to be composed mainly of ions and electrons which are actuated by gravitation, radiation pressure and the magnetic field of the sun.
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