|The Comet (later known as "?" and Cosmology)|
|Categories||Science fiction fanzine|
|First issue||May 1930|
|Company||Science Correspondence Club|
|Based in||Chicago, Illinois|
The fanzine's original editors were Raymond A. Palmer and Walter Dennis. Its second issue, dated July 1930, was called "?", and was the first issue to refer directly to science fiction. The third issue, dated August 1930, took on its third title, Cosmology, a name it retained for the duration of its publication, which ended in 1933.
Comet Ikeya–Zhang (Chinese, Japanese: 池谷-張彗星, officially designated 153P/Ikeya–Zhang) is a comet discovered independently by two astronomers from Japan and China in 2002.
On February 1, 2002, Chinese astronomer Zhang Daqing from Kaifeng discovered a new comet in the constellation Cetus, and reported it to the IAU. He found that Japanese astronomer Kaoru Ikeya had discovered it earlier than he had, as the time of sunset is earlier than China. According to tradition, since they discovered the new comet independently, the comet was named after both of them. The comet was initially designated as C/2002 C1 (Ikeya-Zhang).
The comet was probably observed in 1661, 341 years earlier, by Polish astronomer Johannes Hevelius. A bright comet had also been recorded by Chinese astronomers in 1661.
The permanent designation "153P" was given to the comet. It has the longest known orbital period of any periodic comet (366.51 years).
The comet passed perihelion on March 18, 2002, and with apparent magnitude 3.5, it became the brightest comet since 1997.22P/Kopff
Comet Kopff or 22P/Kopff is a periodic comet in the Solar System. Discovered on August 23, 1906, it was named after August Kopff who discovered the comet. The comet was missed on its November 1912 return, but was recovered on its June 1919 return. The comet has not been missed since its 1919 return and its last perihelion passage was on May 25, 2009. Close approaches to Jupiter in 1938 and 1943 decreased the perihelion distance and orbital period. 22P/Kopff’s next perihelion passage is 18 March 2022.29P/Schwassmann–Wachmann
Comet 29P/Schwassmann–Wachmann, also known as Schwassmann–Wachmann 1, was discovered on November 15, 1927, by Arnold Schwassmann and Arno Arthur Wachmann at the Hamburg Observatory in Bergedorf, Germany. It was discovered photographically, when the comet was in outburst and the magnitude was about 13. Precovery images of the comet from March 4, 1902, were found in 1931 and showed the comet at 12th magnitude.The comet is unusual in that while normally hovering at around 16th magnitude, it suddenly undergoes an outburst. This causes the comet to brighten by 1 to 4 magnitudes. This happens with a frequency of 7.3 outbursts per year, fading within a week or two. The magnitude of the comet has been known to vary from 19th magnitude to 9th magnitude, a ten thousand-fold increase in brightness, during its brightest outbursts. Highly changing surface processes are suspected to be responsible for the observed behavior.The comet is thought to be a member of a relatively new class of objects called "centaurs", of which at least 400 are known. These are small icy bodies with orbits between those of Jupiter and Neptune. Astronomers believe that centaurs are recent escapees from the Kuiper belt, a zone of small bodies orbiting in a cloud at the distant reaches of the Solar System. Frequent perturbations by Jupiter will likely accumulate and cause the comet to migrate either inward or outward by the year 4000.The dust and gas comprising the comet's nucleus is part of the same primordial materials from which the Sun and planets were formed billions of years ago. The complex carbon-rich molecules they contain may have provided some of the raw materials from which life originated on Earth.
The comet nucleus is estimated to be 30.8 kilometers in diameter.29P comes to perihelion on March 7, 2019 and opposition on October 9, 2019.43P/Wolf–Harrington
43P/Wolf–Harrington is a periodic comet discovered on December 22, 1924, by Max Wolf in Heidelberg, Germany. In 2019 it will pass within 0.065 AU (9,700,000 km; 6,000,000 mi) of Jupiter, which will lift the perihelion point and increase the orbital period to 9 years.During the 1997 apparition the comet reached an apparent magnitude a little bit brighter than 12.The comet had an unfavorable apparition in 2010, because during perihelion (closest approach to the Sun), the comet was only 10 degrees from the Sun as seen from Earth. The comet was not more favorably positioned in the sky until mid October 2010.
The comet nucleus is estimated to be 3.6 kilometers in diameter.4P/Faye
4P/Faye (also known as Faye's Comet or Comet Faye) is a periodic Jupiter-family comet discovered in November 1843 by Hervé Faye at the Royal Observatory in Paris. It last came to perihelion (closest approach to the Sun) on May 29, 2014, and will next come to perihelion on September 8, 2021.The comet was first observed by Faye on 23 November, but bad weather prevented its confirmation until the 25th. It was so faint that it had already passed perihelion about a month before its discovery, and only a close pass by the Earth had made it bright enough for discovery. Otto Wilhelm von Struve reported that the comet was visible to the naked eye at the end of November. It remained visible for smaller telescopes until 10 January 1844 and was finally lost to larger telescopes on 10 April 1844.In 1844, Thomas James Henderson computed that the comet was a short period comet; by May, its period had been calculated to be 7.43 years. Urbain Le Verrier computed the positions for the 1851 apparition, predicting perihelion in April 1851. The comet was found close to his predicted position on 28 November 1850 by James Challis.The comet was missed during its apparitions in 1903 and 1918 due to unfavorable observing circumstances. It reached a brightness of about the 9th magnitude in 2006.The comet is estimated at about 3.5 km in diameter.5D/Brorsen
5D/Brorsen (also known as Brorsen's Comet or Comet Brorsen) was a periodic Jupiter-family comet discovered February 26, 1846, by the Danish astronomer Theodor Brorsen.
The perihelion of 5D/Brorsen was February 25, just a day before its discovery, and maintained the approach to Earth after that, passing closest to Earth on March 27 (at a distance of 0.52 AU). As a result of this close encounter to Earth the comet's coma diameter increased. Johann Friedrich Julius Schmidt estimating it as 3 to 4 arcmin across on March 9, and 8 to 10 arcmin across on the 22nd of that same month. Last seen on April 22, it was stationed about 20 degrees from the north celestial pole. By the end of this first apparition the orbital period was identified as 5.5 years. It was discovered that a close approach to Jupiter in 1842 put in its discovery orbit.The comet's 5.5 year period would mean that apparitions would alternate between good and poor. As expected, the comet was missed in its 1851 apparition, when the comet only came as close as 1.5 AU to Earth.
The comet's orbit was still relatively uncertain, made worse by the fact it had approached Jupiter in 1854. In 1857, Karl Christian Bruhns found a comet on 18 March 1857. Soon an orbit was computed and it was found to be 5D/Brorsen, although predictions were three months off. The comet was followed until June 1857, and the orbit was now well known.The comet was missed in 1862, and the next recovery was in 1868. A close approach to Jupiter shortened the period enough to make the comet visible in 1873. A very favorable apparition followed in 1879, allowing the comet to be observed for the longest time to date – four months. The comet was missed in 1884, due to observing circumstances, but was also missed in 1890, a favorable apparition. The next favorable apparition occurred in 1901, but searches did not locate the comet.
The next serious search was started by Brian G. Marsden, who believed the comet had faded out of existence, but computed the orbit for a very favorable 1973 apparition. Japanese observers made intensive searches for the comet, but nothing turned up. The comet is currently considered lost (see lost comet).69P/Taylor
Comet Taylor, is a periodic comet in the solar system, first discovered by Clement J. Taylor (Cape Town, South Africa) on November 24, 1915.
George van Biesbroeck and E. E. Barnard (Yerkes Observatory, Wisconsin, United States) observed that the comet was split into two distinct nuclei, but this was not seen after March 16.
The comet was predicted to return in 1922, but was lost (see lost comet).
In 1928 the discovery of Comet Reinmuth 1 was originally assumed to be Comet Taylor, and again in 1951 the same assumption was made with Comet Arend-Rigaux.
The 1976 return was predicted by N. A. Belyaev and V. V. Emel'yanenko and on January 25, 1977, Charles Kowal (Palomar Observatory, California, United States) found images on photographic plates for December 13, 1976.
The comet was recovered for the returns in 1984 and 1990, and in January 1998 was observed as magnitude 12 when it was 1AU from Earth.There were 6 recovery images of 69P in October 2018 when the comet had a magnitude of about 20.5. Due to the lack of observations, when the comet is at perihelion on March 18, 2019 and 2.45AU from Earth, the 3-sigma uncertainty in the comet's Earth distance will be ±6000 km.72P/Denning–Fujikawa
72P/Denning–Fujikawa is a periodic comet discovered on 4 October 1881 by William Frederick Denning. The comet was not seen at another apparition until recovered by Shigehisa Fujikawa in 1978. From 29 December 1978 until 17 June 2014, the comet was lost. On 17 June 2014 the comet was recovered by Hidetaka Sato.Repeated failures to recover the comet during perihelion even in cases where it is estimated that it should have been magnitude 8 or, as in 1987 and 1996, it was being actively looked for suggest it is only occasionally active. This has resulted in it being classified as a transitional comet.75D/Kohoutek
75D/Kohoutek is a short-period comet discovered in February 1975, by Luboš Kohoutek.
Not to be confused with the much better-known C/1973 E1 (Kohoutek), 75D is a repeat visitor to the inner Solar System, with a period of about seven years. It was placed on the discovery orbit when it passed 0.143 AU (21,400,000 km; 13,300,000 mi) from Jupiter on 28 July 1972. Apparitions have been dim, with the brightest being in 1988 at about apparent magnitude 13. It was last predicted in 2014, but was not seen, nor was it seen in its previous approaches in 2007, in 2000, or in 1994. The comet has been estimated to be 4.6 kilometres (2.9 mi) in diameter.This comet was last observed by Mauna Kea on 19 May 1988. The Minor Planet Center has given the comet a "D/" designation as the comet is believed to be lost. The comet is calculated to come to opposition in October 2020 in the constellation of Pisces.C/1760 A1
The Great Comet of 1760 (C/1760 A1) was first seen on 7 January 1760 by Abbe Chevalier at Lisbon. Charles Messier also spotted the comet on 8 January 1760 in Paris, by the sword of Orion. The comet was his third discovery and the comet was the 51st to have a calculated orbit. Messier observed the comet for a total of 6 days.
It approached the Earth to within approximately 0.0682 astronomical unit (AU) or 6.34 million miles. This is the 17th closest approach by a comet of all time. Messier gave the comet a magnitude rating of 2.0, making it easily visible to the unaided eye. Messier also gave the comet an elongation angle of 140 degrees.
Messier came up against opposition from Navy astronomer Joseph Nicholas Delisle, who had employed Messier from October 1751, because Delisle would not publish the discovery Messier had made. This was a continuation of the mistrust that had developed between Messier and Delisle because Delisle had been slow to publish work done by Messier in 1759; Messier had independently rediscovered Halley's Comet on 21 January 1759 but because Messier had doubted the correctness of Delisle's path, Delisle instructed Messier to continue observing the comet and refused to announce his discovery. Delisle apparently later changed his mind and announced the discovery on 1 April 1759, but other French astronomers discredited Delisle's claim, labelling the discovery an April Fools' joke. Delisle retired in 1760.
As of June 2008, the comet was about 216 AU from the Sun.C/1980 E1 (Bowell)
C/1980 E1 is a non-periodic comet discovered by Edward L. G. Bowell on 11 February 1980. C/1980 E1 is leaving the Solar System on a hyperbolic trajectory with only 1I/ʻOumuamua being on a faster hyperbolic trajectory.Before entering the inner Solar System for a 1982 perihelion passage, C/1980 E1 had a barycentric (epoch 1950-Jan-01) orbit with an aphelion of 74,300 AU (1.17 light-years), and a period of approximately 7.1 million years.As the comet was approaching perihelion on December 9, 1980, it passed within 0.228 AU of Jupiter, which accelerated the comet briefly giving an (epoch 1981-Jan-09) eccentricity of 1.066. The comet came to perihelion on March 12, 1982, when it had a velocity of 23.3 km/s (52,000 mph) with respect to the Sun. Since the epoch of 1977-Mar-04, C/1980 E1 has had a barycentric eccentricity greater than 1, keeping it on a hyperbolic trajectory that will eject it from the Solar System. Objects in hyperbolic orbits have a negative semimajor axis, giving them a positive orbital energy. The Minor Planet Center does not directly list a semimajor axis for this comet.
By May 1995, the comet was 30 AU from the Sun on an ejection trajectory going 8.6 km/s (19,000 mph). Since February 2008, the comet has been more than 50 AU from the Sun.The production of OH (hydroxide) was observed pre-perihelion while the comet was nearly 5 AU from the Sun. CN (cyanide) was not detected until the comet was near perihelion. The comet nucleus was estimated to have a radius of several kilometers. The surface crust was probably a few meters thick.C/2007 W1 (Boattini)
C/2007 W1 (Boattini) is a long-period comet discovered on 20 November 2007, by Andrea Boattini at the Mt. Lemmon Survey. At the peak the comet had an apparent magnitude around 5.On 3 April 2008, when C/2007 W1 was 0.66AU from the Earth and 1.7AU from the Sun, the coma (expanding tenuous dust atmosphere) of the comet was estimated to be as large as 10 arcminutes. This made the coma roughly 290,000 km in diameter.On 12 June 2008, the comet passed within about 0.21005 AU (31,423,000 km; 19,525,000 mi) of the Earth. The comet came to perihelion (closest approach to the Sun) on 24 June 2008 at a distance of 0.8497 AU.The comet has an observation arc of 285 days allowing a good estimate of the orbit. The orbit of a long-period comet is properly obtained when the osculating orbit is computed at an epoch after leaving the planetary region and is calculated with respect to the center of mass of the solar system. Using JPL Horizons, the barycentric orbital elements for epoch 2020-Jan-01 generate a semi-major axis of 1,582 AU, an apoapsis distance of 3,163 AU, and a period of approximately 63,000 years.Before entering the planetary region, C/2007 W1 had a hyperbolic trajectory. The comet was probably in the outer Oort cloud with a loosely bound chaotic orbit that was easily perturbed by passing stars.C/2012 K1
C/2012 K1 (PANSTARRS) is a retrograde Oort cloud comet discovered at magnitude 19.7, 8.7 AU from the Sun on 17 May 2012 using the Pan-STARRS telescope located near the summit of Haleakalā, on the island of Maui in Hawaii (U.S.).The comet started 2014 as a Northern Hemisphere object. By late April 2014 it had brightened to roughly apparent magnitude ~8.8 making it a small telescope/binoculars target for experienced observers. In June and July 2014 the comet was near the Sickle of Leo. As of 3 July 2014 the comet had brightened to magnitude 7.9.From 12 July 2014 until 6 September 2014 it had an elongation less than 30 degrees from the Sun. The comet came to perihelion (closest approach to the Sun) on 27 August 2014 at a distance of 1.05 AU (157,000,000 km; 98,000,000 mi) from the Sun. It crosses the celestial equator on 15 September 2014 becoming a Southern Hemisphere object.The comet peaked around magnitude 6.9 in mid-October 2014 when it had an elongation of around 75 degrees from the Sun. It is visible in binoculars and small telescopes.Coma (cometary)
The coma is the nebulous envelope around the nucleus of a comet, formed when the comet passes close to the Sun on its highly elliptical orbit; as the comet warms, parts of it sublime. This gives a comet a "fuzzy" appearance when viewed in telescopes and distinguishes it from stars. The word coma comes from the Greek "kome" (κόμη), which means "hair" and is the origin of the word comet itself.The coma is generally made of ice and comet dust. Water dominates up to 90% of the volatiles that outflow from the nucleus when the comet is within 3-4 AU of the Sun. The H2O parent molecule is destroyed primarily through photodissociation and to a much smaller extent photoionization. The solar wind plays a minor role in the destruction of water compared to photochemistry. Larger dust particles are left along the comet's orbital path while smaller particles are pushed away from the Sun into the comet's tail by light pressure.
On 11 August 2014, astronomers released studies, using the Atacama Large Millimeter/Submillimeter Array (ALMA) for the first time, that detailed the distribution of HCN, HNC, H2CO, and dust inside the comae of comets C/2012 F6 (Lemmon) and C/2012 S1 (ISON). On 2 June 2015, NASA reported that the ALICE spectrograph on the Rosetta space probe studying comet 67P/Churyumov–Gerasimenko determined that electrons (within 1 km (0.62 mi) above the comet nucleus) produced from photoionization of water molecules by solar radiation, and not photons from the Sun as thought earlier, are responsible for the degradation of water and carbon dioxide molecules released from the comet nucleus into its coma.Comet (Archie Comics)
The Comet is a fictional character that first appeared in Pep Comics #1 in January, 1940. Possibly the first superhero killed in the line of duty, he died in issue #17 (July, 1941), which also introduced his brother, a brutal hero called the Hangman.Comet Hale–Bopp
Comet Hale–Bopp (formally designated C/1995 O1) is a comet that was perhaps the most widely observed of the 20th century, and one of the brightest seen for many decades.
Hale–Bopp was discovered on July 23, 1995, separately by Alan Hale and Thomas Bopp prior to it becoming naked-eye visible on Earth. Although predicting the maximum apparent brightness of new comets with any degree of certainty is difficult, Hale–Bopp met or exceeded most predictions when it passed perihelion on April 1, 1997. It was visible to the naked eye for a record 18 months, twice as long as the previous record holder, the Great Comet of 1811. Accordingly, Hale–Bopp was dubbed the Great Comet of 1997.De Havilland Comet
The de Havilland DH 106 Comet was the world's first commercial jet airliner. Developed and manufactured by de Havilland at its Hatfield Aerodrome in Hertfordshire, United Kingdom, the Comet 1 prototype first flew in 1949. It featured an aerodynamically clean design with four de Havilland Ghost turbojet engines buried in the wing roots, a pressurised cabin, and large square windows. For the era, it offered a relatively quiet, comfortable passenger cabin and was commercially promising at its debut in 1952.
However, within a year of entering airline service, problems started to emerge, with three Comets lost within twelve months in highly publicised accidents, after suffering catastrophic in-flight break-ups. Two of these were found to be caused by structural failure resulting from metal fatigue in the airframe, a phenomenon not fully understood at the time. The other one was due to overstressing of the airframe during flight through severe weather. The Comet was withdrawn from service and extensively tested. Design and construction flaws, including improper riveting and dangerous concentrations of stress around some of the square windows, were ultimately identified. As a result, the Comet was extensively redesigned, with oval windows, structural reinforcements and other changes. Rival manufacturers meanwhile heeded the lessons learned from the Comet while developing their own aircraft.
Although sales never fully recovered, the improved Comet 2 and the prototype Comet 3 culminated in the redesigned Comet 4 series which debuted in 1958 and had a productive career of over 30 years. The Comet was also adapted for a variety of military roles such as VIP, medical and passenger transport, as well as surveillance. The most extensive modification resulted in a specialised maritime patrol variant, the Hawker Siddeley Nimrod, which remained in service with the Royal Air Force until 2011, over 60 years after the Comet's first flight.Deep Impact (spacecraft)
Deep Impact was a NASA space probe launched from Cape Canaveral Air Force Station on January 12, 2005. It was designed to study the interior composition of the comet Tempel 1 (9P/Tempel), by releasing an impactor into the comet. At 05:52 UTC on July 4, 2005, the Impactor successfully collided with the comet's nucleus. The impact excavated debris from the interior of the nucleus, forming an impact crater. Photographs taken by the spacecraft showed the comet to be more dusty and less icy than had been expected. The impact generated an unexpectedly large and bright dust cloud, obscuring the view of the impact crater.
Previous space missions to comets, such as Giotto, Deep Space 1, and Stardust, were fly-by missions. These missions were able to photograph and examine only the surfaces of cometary nuclei, and even then from considerable distances. The Deep Impact mission was the first to eject material from a comet's surface, and the mission garnered considerable publicity from the media, international scientists, and amateur astronomers alike.
Upon the completion of its primary mission, proposals were made to further utilize the spacecraft. Consequently, Deep Impact flew by Earth on December 31, 2007 on its way to an extended mission, designated EPOXI, with a dual purpose to study extrasolar planets and comet Hartley 2 (103P/Hartley). Communication was unexpectedly lost in September 2013 while the craft was heading for another asteroid flyby.Rosetta (spacecraft)
Rosetta was a space probe built by the European Space Agency launched on 2 March 2004. Along with Philae, its lander module, Rosetta performed a detailed study of comet 67P/Churyumov–Gerasimenko (67P). During its journey to the comet, the spacecraft flew by Mars and the asteroids 21 Lutetia and 2867 Šteins. It was launched as the third cornerstone mission of the ESA's Horizon 2000 programme, after SOHO / Cluster and XMM-Newton.
On 6 August 2014, the spacecraft reached the comet and performed a series of manoeuvres to eventually orbit the comet at distances of 30 to 10 kilometres (19 to 6 mi). On 12 November, its lander module Philae performed the first successful landing on a comet, though its battery power ran out two days later. Communications with Philae were briefly restored in June and July 2015, but due to diminishing solar power, Rosetta's communications module with the lander was turned off on 27 July 2016. On 30 September 2016, the Rosetta spacecraft ended its mission by hard-landing on the comet in its Ma'at region.The probe was named after the Rosetta Stone, a stele of Egyptian origin featuring a decree in three scripts. The lander was named after the Philae obelisk, which bears a bilingual Greek and Egyptian hieroglyphic inscription.Sungrazing comet
A sungrazing comet is a comet that passes extremely close to the Sun at perihelion – sometimes within a few thousand kilometres of the Sun's surface. Although small sungrazers can completely evaporate during such a close approach to the Sun, larger sungrazers can survive many perihelion passages. However, the strong evaporation and tidal forces they experience often lead to their fragmentation.
Up until the 1880s, it was thought that all bright comets near the Sun were the repeated return of a single sungrazing comet. Then, German astronomer Heinrich Kreutz and American astronomer Daniel Kirkwood determined that, instead of the return of the same comet, each appearance was a different comet, but each were related to a group of comets that had separated from each other at an earlier passage near the Sun (at perihelion). Very little was known about the population of sungrazing comets until 1979 when coronagraphic observations allowed the detection of sungrazers. As of October 21, 2017, there are 1495 known comets that come within ~12 solar radii (~0.055 AU). This accounts for nearly one third of all comets. Most of these objects vaporize during their close approach, but a comet with a nucleus radius larger than 2–3 km is likely to survive the perihelion passage with a final radius of ~1 km.
Sungrazer comets were some of the earliest observed comets because they can appear very bright. Some are even considered Great Comets. The close passage of a comet to the Sun will brighten the comet not only because the reflection off the comet nucleus when it is closer to the Sun, but the Sun also vaporizes a large amount of gas from the comet and the gas reflects more light. This extreme brightening will allow for possible naked eye observations from Earth depending on how volatile the gases are and if the comet is large enough to survive perihelion. These comets provide a useful tool for understanding the composition of comets as we observe the outgassing activity and they also offer a way to probe the effects solar radiation has on other Solar System bodies.