1.
Aurora
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An aurora, sometimes referred to as a polar lights or northern lights, is a natural light display in the sky, predominantly seen in the high latitude regions. The resulting ionization and excitation of atmospheric constituents emits light of varying colour, the form of the aurora, occurring within bands around both polar regions, is also dependent on the amount of acceleration imparted to the precipitating particles. Precipitating protons generally produce optical emissions as incident hydrogen atoms after gaining electrons from the atmosphere, proton auroras are usually observed at lower latitudes. A region that currently displays an aurora is called the auroral oval, early evidence for a geomagnetic connection comes from the statistics of auroral observations. Elias Loomis, and later Hermann Fritz and S. Tromholt in more detail, day-to-day positions of the auroral ovals are posted on the internet. In northern latitudes, the effect is known as the Aurora Borealis or the Northern Lights, the former term was coined by Galileo in 1619, from the Roman goddess of the dawn and the Greek name for the north wind. The Aurora Australis is visible from southern latitudes in Antarctica, Chile, Argentina, New Zealand. A geomagnetic storm causes the auroral ovals to expand, and bring the aurora to lower latitudes and it was hardly ever seen near the geographic pole, which is about 2000 km away from the magnetic pole. The aurora can be seen best at this time, which is called magnetic midnight, Auroras also occur poleward of the auroral zone as either diffuse patches or arcs, which can be sub-visual. Auroras are occasionally seen in latitudes below the zone, when a geomagnetic storm temporarily enlarges the auroral oval. Large geomagnetic storms are most common during the peak of the sunspot cycle or during the three years after the peak. An aurora may appear overhead as a corona of rays, radiating from a distant and apparent central location, an electron spirals about a field line at an angle that is determined by its velocity vectors, parallel and perpendicular, respectively, to the local geomagnetic field vector B. This angle is known as the “pitch angle” of the particle, the distance, or radius, of the electron from the field line at any time is known as its Larmor radius. The pitch angle increases as the travels to a region of greater field strength nearer to the atmosphere. Thus it is possible for particles to return, or mirror. Other particles that do not mirror enter the atmosphere and contribute to the display over a range of altitudes. Other types of auroras have been observed from space, e. g. poleward arcs stretching sunward across the cap, the related theta aurora. These are relatively infrequent and poorly understood, there are other interesting effects such as flickering aurora, black aurora and sub-visual red arcs
2.
James Craig Watson
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James Craig Watson was a Canadian-American astronomer, discoverer of comets and minor planets, director of the Ann Arbor Observatory, and awarded with the Lalande Prize in 1869. He was born in the village of Fingal, Ontario Canada and his family relocated to Ann Arbor, Michigan in 1850. At age 15 he was matriculated at the University of Michigan and he graduated with a BA in 1857 and received a masters degree on examination after two years study in astronomy under professor Franz Brünnow. He became Professor of Physics and instructor in Mathematics, and in 1863, succeeded him as professor of Astronomy and he wrote the textbook Theoretical Astronomy in 1868. He discovered 22 asteroids, beginning with 79 Eurynome in 1863, one of his asteroid discoveries,139 Juewa was made in Beijing when Watson was there to observe the 1874 transit of Venus. The name Juewa was chosen by Chinese officials, another was 121 Hermione in 1872, from Ann Arbor, Michigan, and this asteroid was found to have a small asteroid moon in 2002. He was a member of the most important expeditions for astronomical observation sent out by the United States Government during his time. He was a believer in the existence of the planet Vulcan, a hypothetical planet closer to the Sun than Mercury. He believed he had seen such two such planets during his observation of the 1878 solar eclipse and he died of peritonitis at the age of only 42 and was buried at Forest Hill, Ann Arbor. He had amassed a considerable amount of money through non-astronomical business activities, by bequest he established the James Craig Watson Medal, awarded every two years by the National Academy of Sciences for contributions to astronomy. Watson won the Lalande Prize given by the French Academy of Sciences for 1869 and he was a member of the National Academy of Sciences and the American Philosophical Society. He received the degree of Doctor of Philosophy from the University of Leipzig in 1870, and from Yale College in 1871. The main-belt asteroid 729 Watsonia is named in his honour, as is the lunar crater Watson, in Search of Planet Vulcan, The Ghost in Newtons Clockwork Machine
3.
Aurora (mythology)
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Aurora is the Latin word for dawn, and the goddess of dawn in Roman mythology and Latin poetry. Like Greek Eos and Rigvedic Ushas, Aurora continues the name of an earlier Indo-European dawn goddess, in Roman mythology, Aurora renews herself every morning and flies across the sky, announcing the arrival of the sun. Her parentage was flexible, for Ovid, she could equally be Pallantis, signifying the daughter of Pallas and she has two siblings, a brother and a sister. Rarely Roman writers imitated Hesiod and later Greek poets and named Aurora as the mother of the Anemoi, who were the offspring of Astraeus, Aurora appears most often in sexual poetry with one of her mortal lovers. A myth taken from the Greek by Roman poets tells that one of her lovers was the prince of Troy, Tithonus was a mortal, and would therefore age and die. Wanting to be with her lover for all eternity, Aurora asked Jupiter to grant immortality to Tithonus, Jupiter granted her wish, but she failed to ask for eternal youth to accompany his immortality, and he became forever old. Aurora turned him into a cicada, but soon as early Dawn appeared, the rosy-fingered, then gathered the folk about the pyre of glorious Hector. In traditional Irish folk songs, such as Lord Courtown One day I was a-musing down by the Courtown banks The sun shone bright and clearly, there was Flora at the helm and Aurora to the stern And all their gallant fine seamen, their course for to steer on. In On Imagination, by Phillis Wheatley From Tithons bed now might Aurora rise, Her cheeks all glowing with celestial dies, Dawn goddess Eos Mater Matuta Memnon Zorya Warburg Institute Iconographic Database Aurora, the Roman goddess of the dawn. Aurora, the goddess of the morning
4.
Minor planet
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A minor planet is an astronomical object in direct orbit around the Sun that is neither a planet nor exclusively classified as a comet. Minor planets can be dwarf planets, asteroids, trojans, centaurs, Kuiper belt objects, as of 2016, the orbits of 709,706 minor planets were archived at the Minor Planet Center,469,275 of which had received permanent numbers. The first minor planet to be discovered was Ceres in 1801, the term minor planet has been used since the 19th century to describe these objects. The term planetoid has also used, especially for larger objects such as those the International Astronomical Union has called dwarf planets since 2006. Historically, the asteroid, minor planet, and planetoid have been more or less synonymous. This terminology has become complicated by the discovery of numerous minor planets beyond the orbit of Jupiter. A Minor planet seen releasing gas may be classified as a comet. Before 2006, the IAU had officially used the term minor planet, during its 2006 meeting, the IAU reclassified minor planets and comets into dwarf planets and small Solar System bodies. Objects are called dwarf planets if their self-gravity is sufficient to achieve hydrostatic equilibrium, all other minor planets and comets are called small Solar System bodies. The IAU stated that the minor planet may still be used. However, for purposes of numbering and naming, the distinction between minor planet and comet is still used. Hundreds of thousands of planets have been discovered within the Solar System. The Minor Planet Center has documented over 167 million observations and 729,626 minor planets, of these,20,570 have official names. As of March 2017, the lowest-numbered unnamed minor planet is 1974 FV1, as of March 2017, the highest-numbered named minor planet is 458063 Gustavomuler. There are various broad minor-planet populations, Asteroids, traditionally, most have been bodies in the inner Solar System. Near-Earth asteroids, those whose orbits take them inside the orbit of Mars. Further subclassification of these, based on distance, is used, Apohele asteroids orbit inside of Earths perihelion distance. Aten asteroids, those that have semi-major axes of less than Earths, Apollo asteroids are those asteroids with a semimajor axis greater than Earths, while having a perihelion distance of 1.017 AU or less. Like Aten asteroids, Apollo asteroids are Earth-crossers, amor asteroids are those near-Earth asteroids that approach the orbit of Earth from beyond, but do not cross it
5.
Asteroid belt
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The asteroid belt is the circumstellar disc in the Solar System located roughly between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called asteroids or minor planets, the asteroid belt is also termed the main asteroid belt or main belt to distinguish it from other asteroid populations in the Solar System such as near-Earth asteroids and trojan asteroids. About half the mass of the belt is contained in the four largest asteroids, Ceres, Vesta, Pallas, the total mass of the asteroid belt is approximately 4% that of the Moon, or 22% that of Pluto, and roughly twice that of Plutos moon Charon. Ceres, the belts only dwarf planet, is about 950 km in diameter, whereas Vesta, Pallas. The remaining bodies range down to the size of a dust particle, the asteroid material is so thinly distributed that numerous unmanned spacecraft have traversed it without incident. Nonetheless, collisions between large asteroids do occur, and these can form a family whose members have similar orbital characteristics. Individual asteroids within the belt are categorized by their spectra. The asteroid belt formed from the solar nebula as a group of planetesimals. Planetesimals are the precursors of the protoplanets. Between Mars and Jupiter, however, gravitational perturbations from Jupiter imbued the protoplanets with too much energy for them to accrete into a planet. Collisions became too violent, and instead of fusing together, the planetesimals, as a result,99. 9% of the asteroid belts original mass was lost in the first 100 million years of the Solar Systems history. Some fragments eventually found their way into the inner Solar System, Asteroid orbits continue to be appreciably perturbed whenever their period of revolution about the Sun forms an orbital resonance with Jupiter. At these orbital distances, a Kirkwood gap occurs as they are swept into other orbits. Classes of small Solar System bodies in other regions are the objects, the centaurs, the Kuiper belt objects, the scattered disc objects, the sednoids. On 22 January 2014, ESA scientists reported the detection, for the first definitive time, of water vapor on Ceres, the detection was made by using the far-infrared abilities of the Herschel Space Observatory. The finding was unexpected because comets, not asteroids, are considered to sprout jets. According to one of the scientists, The lines are becoming more and more blurred between comets and asteroids. This pattern, now known as the Titius–Bode law, predicted the semi-major axes of the six planets of the provided one allowed for a gap between the orbits of Mars and Jupiter
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, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009. See Table 1.
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