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In August 1908, a white mob attacked Springfield, Illinois’s Black community, destroying homes and businesses and lynching two Black men. National outrage over the violence helped spur the movement that created the NAACP the following year.
MORE →Reflects the personal views, recollections, and perspective of the author, Mike Davis.
This is a personal recollection on the Move fire on May 13, 1985
 Photograph of the comet taken by David Gill in Cape Town on 7 November 1882 | |
| Discovery | |
|---|---|
| Discovery date | 1 September 1882 |
| Designations | |
| 1882 II, 1882b[1] | |
| Orbital characteristics[3][4][5][6] | |
| Epoch | 21 September 1882 (JD 2408709.5) |
| Observation arc | 110–153 days |
| Number of observations | 4–10 |
| Orbit type | Kreutz sungrazer (Population II) |
| Aphelion |
|
| Perihelion | 0.0077 AU |
| Semi-major axis |
|
| Eccentricity |
|
| Orbital period | ≈670–950 years |
| Inclination | 142° |
| 347.65° | |
| Argument of periapsis | 69.58° |
| Last perihelion | 17 September 1882 |
| Next perihelion | 2487–2719[2] |
| TJupiter |
|
| Earth MOID | 0.5164 AU |
| Jupiter MOID | 2.9096 AU |
| Physical characteristics | |
Mean radius | 29.65 km (18.42 mi)[7][a] |
| Mass | 4.20×1019 kg[8] |
| Comet total magnitude (M1) | 0.8[10] |
| –17.0 (1882 apparition)[9] | |
The Great Comet of 1882, formally designated as C/1882 R1, 1882 II, and 1882b, was a comet which became very bright in September 1882. It is classified as one of the Kreutz sungrazers, a family of comets which pass within 1 R☉ of the Sun's photosphere at perihelion.[2][11]
The comet was bright enough to be visible next to the Sun in the daytime sky at its perihelion.[12] The comet made its closest approach to Earth on 16 September 1882 at 0.99 AU and then came to perihelion (closest approach to the Sun) the next day on 17 September.[13] Reaching a peak magnitude of –17, some sources claim that C/1882 R1 is the brightest comet ever recorded in history.[9][14][15]
The comet appeared in the morning skies of September 1882. Reports suggest that it was first seen as early as 1 September 1882, from the Cape of Good Hope as well as the Gulf of Guinea, and over the next few days many observers in the Southern Hemisphere reported the new comet.[16]
The first astronomer to record observations of the comet was W. H. Finlay,[17] the Chief Assistant at the Royal Observatory in Cape Town, South Africa. Finlay's observation on 7 September 1882, 16:00 GMT was also an independent discovery,[12] and he reported that the comet had an apparent magnitude of about 3, and a tail about a degree in length.[18][19]
The comet brightened rapidly, and within days had become an exceptionally bright object. Her Majesty's Astronomer at the Cape, David Gill, reported watching the comet rise a few minutes before the Sun on 18 September, and described it: "The nucleus was then undoubtedly single, and certainly rather under than over 4″ in diameter; in fact, as I have described it, it resembled very much a star of the 1st magnitude seen by daylight."[b][20]
The comet was rapidly approaching perihelion when it was first seen. At perihelion, the comet is estimated to have been only 300,000 miles or 480,000 kilometres (0.0032 AU) from the Sun's surface.[11] Subsequent orbital studies have determined that it was a sungrazing comet, one which passes extremely close to the surface of the Sun. For many hours on either side of its perihelion passage, the comet was easily visible in the daytime sky next to the Sun. It reached an estimated magnitude of −17.[9]
Shortly after perihelion was reached on 17 September, the comet transited the Sun.[21] At the Cape, Finlay observed the comet with the aid of a neutral density filter right up until the moment of transit, when the Sun's limb was "boiling all about it". Finlay noted that the comet disappeared from view very suddenly, and no trace of it could be seen against the Sun's surface.[19]
After its perihelion passage, the comet moved into dark skies, and although it faded as it receded from the Sun it remained one of the most prominent objects in the sky. On 30 September, observers, including Finlay and E. E. Barnard,[20] began to notice that the comet's nucleus was elongated[11] and broken into two pronounced bright balls of light,[20] and by 17 October it was clear that it had broken[11] into at least five fragments.[20] Observers reported that the relative brightness of the fragments varied from day to day.[11]
The nucleus reached its maximum apparent size in December 1882.[20] The comet faded gradually, but despite its fragmentation it remained visible to the naked eye until February 1883. The last definite sighting of the comet was made by B. A. Gould at Córdoba on 1 June 1883.[11][22]
Studies of the orbit of the comet showed that the Great Comet of 1882 was moving on an almost identical path to previous great comets seen in C/1843 D1 and C/1880 C1.[11] These comets had also suddenly appeared in the morning sky and had passed extremely close to the Sun at perihelion.[11] One suggestion was that all three were in fact the same comet, with an orbital period that was being drastically shortened at each perihelion passage.[11] However, studies showed this to be untenable, as the orbital period of this comet is 772 ± 3 years[11] and the others are 600–800 years.[citation needed]
Heinrich Kreutz studied the orbits of the three great comets, and developed the idea that the three comets were fragments of a much larger progenitor comet which had broken up at an earlier perihelion passage. The fragmentation of the Great Comet of 1882 itself demonstrated that this was plausible. It is now thought that the Great Comet of 1882 is a fragment of a comet that passed perihelion in early 12th century,[2] and that C/1945 X1 (du Toit) and C/1965 S1 (Ikeya–Seki) are two of its sister fragments.[23] It is now well established that the comets C/1843 D1, C/1880 C1, C/1882 R1, C/1887 B1, C/1963 R1, C/1965 S1, and C/1970 K1 are all members of a family known as the Kreutz sungrazers, which are all descended from one comet.[2]
Brian G. Marsden suggested that the comet of 372–371 BC may have been the source of the group.[24][25] However, more recent models do not support this supposition. The comet of 372–371 BC is often associated with Aristotle who, along with others from his time, described that comet in his writings. However, Aristotle was only twelve at the time of the comet's appearance and the historian, Callisthenes of Olynthus, who also wrote about it was born ten years after its appearance. Consequently, their reports should not be taken as eyewitness accounts. Further, there is no mention of the comet in Chinese literature of the time. Instead either the comet of February 423 or of February 467 with orbital periods of around 700 years is now considered the likely progenitor of the Sungrazers. Fragments of the Great Comet of 1882 should return around 2487 (A) to 2719 (D).[2]
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Source: Wikipedia. Article content is retrieved live through the MediaWiki API.
A great comet is a comet that becomes exceptionally bright and easily observable to the naked eye. There is no official definition; the term is often attached to comets such as Halley's Comet, which, during certain appearances, are bright enough to be noticed by casual observers not looking for them and become well known outside the astronomical community. Typically, they are as bright or brighter than a second-magnitude star and have tails that are 10 degrees or longer under dark skies. Great comets appear at irregular, unpredictable intervals, on average about once per decade. Although comets are officially named after their discoverers, great comets are sometimes also referred to by the year in which they appeared great, by using the formulation "The Great Comet of ...", followed by the year. The term can also be used as a generic name when a very bright comet is discovered by many observers simultaneously.
The Great Comet of 1811, formally designated C/1811 F1, is a comet that was visible to the naked eye for around 260 days, the longest recorded period of visibility until the appearance of Comet Hale–Bopp in 1997. In October 1811, at its brightest, and when it was 1.2 AU from Earth, it displayed an apparent magnitude of 0, with an easily-visible coma.
The Great Comet of 1843, formally designated C/1843 D1 and 1843 I, was a long-period comet which became very bright in March 1843 (it is also known as the Great March Comet). It was discovered on February 5, 1843, and rapidly brightened to become a great comet. It was a member of the Kreutz sungrazers, specifically the Population I subgroup that originated from the breakup of a large parent comet in February 1106. These comets pass extremely close to the surface of the Sun—within a few solar radii—and often become very bright as a result.
The Great Comet of 1882, formally designated as C/1882 R1, 1882 II, and 1882b, was a comet which became very bright in September 1882. It is classified as one of the Kreutz sungrazers, a family of comets which pass within 1 R☉ of the Sun's photosphere at perihelion. The comet was bright enough to be visible next to the Sun in the daytime sky at its perihelion. The comet made its closest approach to Earth on 16 September 1882 at 0.99 AU and then came to perihelion (closest approach to the Sun) the next day on 17 September. Reaching a peak magnitude of –17, some sources claim that C/1882 R1 is the brightest comet ever recorded in history.
Before the 1921 destruction of Tulsa’s Greenwood District, Black residents had created a remarkable center of business and community life. The district included stores, professional offices, entertainment venues and homes owned by Black citizens. Understanding Greenwood means learning what was built—not only what was burned.
MORE →Mae Jemison, aboard Space Shuttle Endeavour in 1992.
