After a struggle to claim the throne, Isabella reorganized the governmental system, brought the crime rate down, and unburdened the kingdom of the debt, which her half-brother King Henry IV had left behind. Isabella's marriage to Ferdinand in 1469 created the basis of the de facto unification of Spain. Her reforms and those she made with her husband had an influence that extended well beyond the borders of their united kingdoms.[4]
Isabella was born in Madrigal de las Altas Torres to King John II of Castile and his second wife, Isabella of Portugal, on 22 April 1451.[6] At the time of Isabella's birth, she was second in line to the throne after her older half-brother Henry.[5] Henry was 26 at that time and married, but childless. Isabella's younger brother Alfonso was born two years later on 17 November 1453, demoting her position to third in line.[7] When her father died in 1454, her half-brother ascended to the throne as King Henry IV. Isabella and her brother Alfonso were left in King Henry's care.[8] Isabella, her mother, and Alfonso then moved to Arévalo.[5][9]
These were times of turmoil for Isabella. The living conditions at their castle in Arévalo were poor, and they suffered from a shortage of money. Although her father arranged in his will for his children to be financially well taken care of, King Henry did not comply with their father's wishes, either from a desire to keep his half-siblings restricted or from ineptitude.[8] Even though her living conditions were difficult, Isabella was instructed in lessons of practical piety and in a deep reverence for religion under the supervision of her mother.[9]
When the king's wife, Joan of Portugal, was about to give birth to their daughter Joanna, Isabella and her brother Alfonso were summoned to court in Segovia to come under the direct supervision of the king and to finish their education.[5] Alfonso was placed in the care of a tutor while Isabella became part of the queen's household.[10]
Isabella in the Rimado de la Conquista de Granada, from 1482, by Pedro Marcuello
Some of Isabella's living conditions improved in Segovia. She always had food and clothing and lived in a castle that was adorned with gold and silver. Isabella's basic education consisted of reading, spelling, writing, grammar, history, arithmetic, art, chess, dancing, embroidery, music, and religious instruction. She and her ladies-in-waiting entertained themselves with art, embroidery, and music. She lived a relaxed lifestyle, but she rarely left Segovia since King Henry forbade this. Her half-brother was keeping her from the political turmoil going on in the kingdom, though Isabella had full knowledge of what was going on and of her role in the feuds.[11][better source needed]
After a rumor spread that Joanna was not actually the daughter of King Henry but rather of a royal favorite, Beltrán de la Cueva, noblemen confronted King Henry and demanded that the king's younger half-brother Alfonso be named his successor. They even went so far as to ask Alfonso to seize the throne. The nobles, now in control of Alfonso and claiming that he was the true heir, clashed with King Henry's forces at the Second Battle of Olmedo in 1467. The battle was a draw. King Henry agreed to recognize Alfonso as his heir presumptive, provided that he would marry his daughter, Princess Joanna.[5][12] Soon after he was named Prince of Asturias, he died at the age of fourteen in July 1468. The nobles who had supported him suspected poisoning. As she had been named in her brother's will as his successor, the nobles asked Isabella to take his place as champion of the rebellion.[5] However, support for the rebels had begun to wane, and Isabella preferred a negotiated settlement to continuing the war.[13] She met with her elder half-brother Henry at Toros de Guisando and they reached a compromise: the war would stop, King Henry would name Isabella his heir presumptive instead of his daughter Joanna, and Isabella would not marry without her half-brother's consent, but he would not be able to force her to marry against her will.[5][14] Isabella's side came out with most of what the nobles desired, though they did not go so far as to officially depose King Henry; they were not powerful enough to do so, and Isabella did not want to jeopardize the principle of fair inherited succession, since it was upon this idea that she had based her argument for legitimacy as heir-presumptive.
The question of Isabella's marriage was not a new one. She had, at the age of six, a betrothal to Ferdinand, the younger son of John II of Navarre (whose family was a cadet branch of the House of Trastámara). At that time, the two kings, Henry and John, were eager to show their mutual love and confidence and they believed that this alliance would make their eternal friendship obvious to the world.[15] This arrangement, however, did not last long.
The wedding portrait of Ferdinand and Isabella, c. 1469
Ferdinand's uncle Alfonso V of Aragon died in 1458. All of Alfonso's Spanish territories, as well as the islands of Sicily and Sardinia, were left to his brother John II. John now had a stronger position than ever before and no longer needed the security of Henry's friendship. Henry was now in need of a new alliance. He saw the chance for this much-needed new friendship in Charles of Viana, John's elder son.[16] Charles was constantly at odds with his father, and because of this, he secretly entered into an alliance with Henry IV of Castile. A major part of the alliance was that a marriage was to be arranged between Charles and Isabella. When John II learned of this arranged marriage, he was outraged. Isabella had been intended for his favorite younger son, Ferdinand, and in his eyes, this alliance was still valid. John II had his son Charles thrown in prison on charges of plotting against his father's life. Charles died in 1461.[17]
In 1465, an attempt was made to marry Isabella to Afonso V of Portugal, Henry's brother-in-law.[5] Through the medium of the queen and Count of Ledesma, a Portuguese alliance was made.[18] Isabella, however, was wary of the marriage and refused to consent.[19]
A civil war broke out in Castile over King Henry's inability to act as sovereign. Henry now needed a quick way to please the rebels of the kingdom. As part of an agreement to restore peace, Isabella was then to be betrothed to Pedro Girón Acuña Pacheco, Master of the Order of Calatrava and brother to the king's favorite, Juan Pacheco.[18] In return, Don Pedro would pay into the royal treasury an enormous sum of money. Seeing no alternative, Henry agreed to the marriage. Isabella was aghast and prayed to God that the marriage would not come to pass. Her prayers were answered when Don Pedro suddenly fell ill and died while on his way to meet his fiancée.[18][20]
When Henry had recognized Isabella as his heir-presumptive on 19 September 1468, he had also promised that his half-sister should not be compelled to marry against her will, while she in return had agreed to obtain his consent.[5][14] It seemed that the years of failed attempts at political marriages were finally over. There was talk of a marriage to Edward IV of England or to one of his brothers, probably Richard, Duke of Gloucester,[21] but this alliance was never seriously considered.[14] Once again in 1468, a marriage proposal arrived from Afonso V of Portugal. Going against his promises made in September 1468, Henry tried to make the marriage a reality. If Isabella married Afonso, Henry's daughter Joanna would marry Afonso's son John II and thus, after the death of the old king, John and Joanna could inherit Portugal and Castile.[22] Isabella refused and made a secret promise to marry her cousin and very first betrothed, Ferdinand of Aragon.[5]
Not much is know about the caravel, where and when built unknown. Tonnage 200 ton, dim. 85 x 25 x 14ft. (draught) Four masts, fore and main mast square rigged, mizzen and Bonaventura mast lateen rigged.
She was the flagship of Don Pedro de Mendoza (1487-1537) expedition to the River Plata. Mendoza held a post in the court of Charles V, when he in 1534 made an offer to Emperor Charles V to make an expedition on his own account for the discovery and conquest of Paraguay and the countries on the Rio La Plata. 24 August 1534 Mendoza on board the MAGDALENA and 13 other vessels, with 3000 men set sail from San Lucar, Spain. Receive from the Emperor before sailing 2.000 ducats, with the condition, when he transported to the new founded colonies 1000 colonists and 100 horses, build a road to the Pacific Ocean, erect three forts within two years he would receive 2.000 ducats more. Also he had to take 8 monks, a physician, a surgeon, and an apothecary, but he was forbidden to introduce a lawyer in the colony. He was to have half the treasure of the chiefs killed and nine-tenths of the ransom. Mendoza was made before sailing military governor of all the territory between the Rio de la Plata and the Strait of Magellan. The office of the Governor was also made hereditary.
Off the coast of Brazil the fleet was scattered in a heavy storm, and Medoza lieutenant Osario, was assassinated, according to some authorities by the orders of Mendoza himself because of suspected disloyalty. 1535 Mendoza sailed up the Rio de la Plata, and founded Buenos Aires on 02 February 1536. He erected two forts there to defend the place. Pestilence broke out and the natives became unfriendly after ill treatment by the Spaniards. His brother Don Diego led a force against the hostile tribes, but was killed with three-fourths of his men. A general conspiracy of the natives was formed, and Buenos Aires was captured and burned by the natives. Mendoza retired to the forth Sanctus-Spiritus, from where he dispatched Juan de Ayolas to explore the upper part of the river. Another brother, Gonzalo arrived with reinforcements and founded the city of Ascención in Paraguay in 1536. Mendoza, disappointed and with a broken health, embarked on board the MAGDALENA for Spain in 1537, leaving Juan de Ayolas in charge. During the long voyage to Spain he died maniac on board the MAGDALENA on 23 June 1537.
The Board of Lady Managers, headed by Chicago socialite Bertha Palmer, wanted a woman to design the coin and engaged Caroline Peddle, a sculptor. Peddle left the project after disagreements with Mint officials, who then decided to have Barber do the work. The reverse design, showing a kneeling woman spinning flax, with a distaff in her left hand and a spindle in her right, symbolizes women's industry and was based on a sketch by Assistant Engraver George T. Morgan.
The quarter's design was deprecated in the numismatic press. The coin did not sell well at the Exposition; its price of $1 was the same as for the Columbian half dollar, and the quarter was seen as the worse deal. Nearly half of the authorized issue was returned to the Mint to be melted; thousands more were purchased at face value by the Lady Managers and entered the coin market in the early 20th century. Today, they are popular with collectors and are valued in the hundreds to thousands of dollars, depending on condition.
In August 1892, Congress passed an act authorizing the first United States commemorative coin, a half dollar, to be sold at a premium by the managers of the World's Columbian Exposition in Chicago.[1] The event had been authorised by Congress two years previously; that legislation created a Board of Lady Managers and a Board of Gentleman Managers to oversee the fair. The Board of Lady Managers was headed by Bertha Palmer, whose husband Potter owned the Palmer House, the leading hotel in Chicago. The decisions of the Lady Managers were often reversed by their male counterparts on controversial matters: for example, Palmer sought to shut the fair's "Egyptian Girls" dancing show after deeming it obscene. The show was one of the exposition's few successful moneymakers, and the Lady Managers were overruled by the men.[2][3]
Bertha Palmer led the Exposition's Board of Lady Managers
Authorization for the Board of Lady Managers had been included in the 1890 law giving federal authority for the Exposition at the insistence of women's advocate, Susan B. Anthony, who was determined to show that women could successfully assist in the management of the fair. To that end, the Lady Managers sought a coin to sell in competition with the commemorative half dollar at the Exposition, which Congress had approved in 1892.[3] Passage of the half dollar legislation had been difficult, and the Lady Managers decided to wait until the next session of Congress to make their request. When the half dollar appeared in November 1892, the Lady Managers considered it inartistic and determined to do better. Palmer wanted the Lady Managers "to have credit of being the authors of the first really beautiful and artistic coin that has ever been issued by the government of the United States".[4]
In January 1893, Palmer approached the House Appropriations Committee, asking that $10,000 of the funds already designated to be paid over to the Lady Managers by the federal government be in the form of souvenir quarters, which they could sell at a premium. On March 3, 1893, Congress duly passed an act authorising the souvenir coin, which was to be to the specifications of the quarter struck for circulation, and with a design to be approved by the Secretary of the Treasury. Total mintage of the special quarter would be limited to 40,000 specimens.[3][4]
In 1893, Queen Isabella of Spain became the first woman featured on a United States coin, the Queen Isabella Commemorative Quarter. It was almost 100 years later, in 1979, that the first U.S. circulating coin depicted a woman. Since then, there have been a limited number of other circulating coins celebrating women. Although coin designs should represent a country’s values and culture, women are historically under-represented on American coins. But this year, the American Women Quarters™ Program brings recognition to women and their contributions to this country.
Women on Circulating Coins
Although U.S. circulating coins from the 18th to early 20th centuries portrayed female likenesses, they all depicted the mythical figure of Liberty. When creating legislation for a national mint, Congress decided that coins should represent the concept of liberty on the obverse rather than a real person. In early America, symbols of liberty as a Greco-Roman goddess were prevalent. Because of those origins, early coin designs portrayed her with classically styled clothes, facial features, and symbols.
By the early 20th century, opinions about featuring real people on coins changed, and President Abraham Lincoln replaced the figure of Liberty on the penny in 1909. The other circulating coins changed throughout the first half of the 20th century to show different presidents. Legislation still required the obverse of coins to represent the concept of liberty, but instead of a mythical figure, the presidents became that depiction.
Almost 200 years after the Mint produced its first circulating coin, Susan B. Anthony appeared on the dollar. The Susan B. Anthony Dollar was the first circulating coin to depict a non-mythical woman. Her portrait replaced President Dwight D. Eisenhower on the obverse. The reverse continued to include an adaptation of Apollo 11’s insignia used on the Eisenhower Dollar. The Mint produced the Susan B. Anthony Dollar from 1979 to 1981 and again in 1999.
The Sacagawea Golden Dollar replaced the Susan B. Anthony Dollar. The obverse showed Sacagawea carrying her baby Jean Baptiste on her back. Her portrait is unlike the traditional side-facing image; she is in three-quarters profile and looks out at the viewer. The reverse featured a soaring eagle. The Mint made the Sacagawea Golden Dollar from 2000 to 2008, before it transitioned into the Native American $1 Coin Program in 2009.
Both the Susan B. Anthony and Sacagawea dollars are unique because their portraits appear on the obverse. They are the representations of liberty instead of a male president.
1979 Susan B. Anthony Dollar and 2000 Sacagawea Golden Dollar
Circulating coin reverse designs follow different themes named in legislation, including as part of coin programs. Some of these coins show women as part of the design. The 2003 Alabama State Quarter featured Helen Keller. But even though her image was in the design, the quarter was part of the 50 State Quarters Program and honored Alabama, not Helen Keller herself.
American Women Quarters Program
The American Women Quarters Program is the first circulating coin program to exclusively honor women and their contributions to this country as the reverse theme. From 2022 through 2025, the Mint will release five designs each year recognizing a different American woman.
The women will be from ethnically, racially, and geographically diverse backgrounds and from a variety of fields. The program will celebrate familiar names such as author Maya Angelou and Dr. Sally Ride, the first American woman in space. It will also introduce Americans to under-recognized women such as Anna May Wong, the first Chinese American film star in Hollywood.
The obverse of the quarters will still depict George Washington, but in a new design sculpted by famous 20th century artist Laura Gardin Fraser. Her right-facing portrait of Washington was the recommended design for the 1932 quarter when the obverse changed from Liberty to Washington. The Treasury Secretary at the time ultimately selected the familiar left-facing portrait by John Flanagan, which the Mint used on the quarter for 90 years.
Watch for these quarters in circulation or buy American Women Quarters Program products in the Mint’s online catalog.
1893 Queen Isabella Commemorative Quarter. (Image via me)
A few things I’ve picked up from researching early commemorative coins:
The people behind them always hope they can raise a ton of money for a pet project or monument or expo. They rarely do.
The designs usually get denigrated by the numismatic press – oftentimes with a venom critics reserve for Limp Bizkit albums or Michael Bay movies.
The mint melts down the excess/unsold coins. As a result, the ones that did sell end up becoming valuable decades later – screwing over collectors on a budget like yours truly.
Those issues were all in play for the 1893 Isabella Quarter.
The Queen Isabella commemorative quarter traces its beginnings to the World’s Fair: Columbian Exposition, held in Chicago in 1893. Congress had already authorized the minting of a commemorative half dollar featuring Christopher Columbus, but a group of women, led by Bertha Palmer, whose husband, Potter, owned the famed Palmer House hotel in Chicago, thought they could do better.
Spearheaded by renowned women’s rights activist, and future $1 coin subject, Susan B. Anthony, the Board of Lady Managers had been awarded $10,000 in federal funds to help manage the Columbian Expo. In early 1893, the Board went before the House Appropriations Committee to ask that the $10,000 could be paid to them in the form of 40,000 specially designed commemorative quarters, which they could then sell at a profit. Congress obliged and the Board set about becoming “the authors of the first really beautiful and artistic coin that has ever been issued by the government of the United States.”
Obviously, the Board wanted a female on the obverse and decided on Queen Isabella I of Castile, who had provided vital financial support for Columbus’s voyages. Putting a foreign monarch on U.S. currency was unprecedented (indeed, there had a been a revolution over it), but according to Coin Week, the main source of conflict was over design.
Caroline Peddle, a former student of famed artist and coin designer Augustus Saint-Gaudens, was hired by the Board to design the coin. However, her sketches, which included a seated Isabella on the obverse and the inscription “Commemorative coin issued for the Board of Lady Managers of the World’s Columbian Exposition by Act of Congress, 1492–1892” on the reverse, were deemed to look too token-like and rejected. Rather than be allowed to redesign the coin, the Mint took away the reverse side and gave it to one of their in-house artists, Charles Barber, to design.
After some more back-and-forth and additional restrictions imposed by the Mint, Peddle resigned. The Mint then cobbled together some portraits of Isabella and ultimately produced an image of a young Isabella wearing a crown on her head for the obverse. On the reverse, the Mint went with an image of a woman kneeling while holding a distaff and spindle- symbolizing her industry. The Board had suggested an image of the Woman’s Building at the Expo, and Palmer later stated that the Board disliked the Mint’s reverse image because “we did not consider [it] typical of the woman of the present day.” However, the Mint made the final decision and approved the coin design.
To say that the reception for the commemorative quarter was not warm is a bit like saying that the American public didn’t embrace Apple’s Newton. The American Journal of Numsimatics was particularly brutal:
[W]e do not know who designed it, but in this instance, as in the half dollar, the contrast between examples of the numismatic art of the nation, as displayed on the Columbian coins, on the one hand, and the spirited and admirable work of the architects of the buildings, for instance, on the other, is painful. If these coins really represent the highest achievements of our medalist and our mints, under the inspiration of an opportunity without restrictions, the like of which has never been presented hitherto in the history of our national coinage, we might as well despair of its future…
The American Journal of Numismatics in October 1893, quoted by PCGS.
The Journal also drew a “mournful” comparison between the reverse design of the kneeling woman holding the distaff and spindle and the well-known “Am I Not a Woman and a Sister?” anti-slavery Hard Times Token. Surely, the Board felt vindicated by that line – although there’s no evidence Palmer or anyone else affiliated with them ever wrote to the Mint to say: “See? I told you we should gone with the building on the reverse.”
1838 HT-81 “Am I Not A Woman & A Sister?” (Image via me)
Sales figures, meanwhile, were disappointing. Of the 40,000 coins minted, a little more than half (21,180) ended up selling. According to NGC, the quarter’s sales were cannibalized by the Columbian Expo half dollar, which sold for the same price and was more widely available at the fair (5 million Columbian Expo half dollars were minted – 125 times as many compared to the Isabella quarter). While it didn’t come close to selling out, Coin Week points out that the quarters, which sold for $1 each, ended up being profitable for the Board. A $20,000-plus stream of revenue may not have been much, but it was double the original federal appropriation awarded to the Board. Of the remaining 19,000-plus quarters, approximately 15,000 went back to the Mint for melting.
1893 Columbian Expo Half Dollar. (Image via me)
In recent years, the coin’s reputation has been rehabilitated and has become a highly sought-after collector’s item. Contemporary reviewers have praised its quaint design and its uniqueness among U.S. commemorative coins (until the modern commemoratives came around, it held the distinction as the only commemorative quarter in U.S. history – as well as the only one to depict a foreign monarch). Even the reverse of the coin has been somewhat vindicated. Art historian Cornelius Vermeule argued that the design wasn’t necessarily evocative of the anti-slavery token and even traced elements of it back to antiquities. “[S]ome details of drapery to a servant girl from the East Pediment of the Temple of Zeus at Olympia, work of about 460 B.C. with additions and revisions in the first or second centuries A.D.,” he wrote.
I love the design and how it distinguishes this coin from other early commemoratives. Too many coins from that era have a generic male bust on the obverse and either an eagle or state symbol on the reverse. Because of the relative scarcity of this coin, buying one wasn’t cheap (this one had been cleaned, which lowered its value, but it still ended up costing over $100). The price tag was worth it, as this has become one of my favorite coins.
So I guess the lesson here is that I should buy more modern commemoratives – even those that I think are ugly. After all, maybe they’ll skyrocket in value in 100 years…
Viking fue la culminación de una serie de misiones para explorar el planeta Marte ; comenzaron en 1964 con el Mariner 4, y continuaron con los sobrevuelos del Mariner 6 y 7 en 1969, y la misión orbital del Mariner 9 en 1971 y 1972.
La Viking fue diseñada para orbitar Marte y aterrizar y operar en la superficie del planeta. Se construyeron dos naves espaciales idénticas, cada una compuesta por un módulo de aterrizaje y un orbitador.
El Centro de Investigación Langley de la NASA en Hampton, Virginia, fue el responsable de la gestión del proyecto Viking desde su inicio en 1968 hasta el 1 de abril de 1978, cuando el Laboratorio de Propulsión a Chorro asumió la tarea. Martin Marietta Aerospace en Denver, Colorado, desarrolló los módulos de aterrizaje. El Centro de Investigación Lewis de la NASA en Cleveland, Ohio, fue el responsable de los vehículos de lanzamiento Titán-Centauro. La tarea inicial del JPL fue el desarrollo de los orbitadores, el seguimiento y la adquisición de datos, y el Centro de Control de Misión y Computación.
La NASA lanzó ambas naves espaciales desde Cabo Cañaveral, Florida: la Viking 1 el 20 de agosto de 1975 y la Viking 2 el 9 de septiembre de 1975. Las sondas fueron esterilizadas antes del lanzamiento para evitar la contaminación de Marte con organismos de la Tierra. La nave espacial pasó casi un año navegando hacia Marte. La Viking 1 alcanzó la órbita de Marte el 19 de junio de 1976; la Viking 2 comenzó a orbitar Marte el 7 de agosto de 1976.
Después de estudiar las fotografías del orbitador, el equipo de certificación del sitio de aterrizaje de Viking consideró que el lugar de aterrizaje original de Viking 1 no era seguro. El equipo examinó los sitios cercanos y Viking 1 aterrizó el 20 de julio de 1976 en la ladera occidental de Chryse Planitia (las llanuras de oro) a 22,3° de latitud norte y 48,0° de longitud.
El equipo de certificación del sitio también decidió que el lugar de aterrizaje planeado para Viking 2 no era seguro después de examinar fotografías de alta resolución. La certificación de un nuevo lugar de aterrizaje se llevó a cabo a tiempo para un aterrizaje en Marte el 3 de septiembre de 1976, en Utopia Planitia, a 47,7° de latitud norte y 225,8° de longitud.
La misión Viking estaba prevista para continuar durante 90 días después del aterrizaje. Cada orbitador y módulo de aterrizaje funcionó mucho más allá de su vida útil prevista. El Viking Orbiter 1 superó los cuatro años de operaciones de vuelo activas en la órbita de Marte.
La misión principal del proyecto Viking finalizó el 15 de noviembre de 1976, 11 días antes de la conjunción superior de Marte (su paso por detrás del Sol). Después de la conjunción, a mediados de diciembre de 1976, los controladores restablecieron las operaciones de telemetría y comando y comenzaron las operaciones de la misión extendida.
La primera nave espacial que dejó de funcionar fue la Viking Orbiter 2 el 25 de julio de 1978; la nave espacial había utilizado todo el gas de su sistema de control de actitud, que mantenía los paneles solares de la nave apuntando al Sol para alimentar el orbitador. Cuando la nave espacial se alejó de la línea del Sol, los controladores del JPL enviaron órdenes para apagar el transmisor de la Viking Orbiter 2.
En 1978, la Viking Orbiter 1 empezó a quedarse sin gas para el control de actitud, pero gracias a una cuidadosa planificación para conservar el suministro restante, los ingenieros descubrieron que era posible seguir adquiriendo datos científicos a un nivel reducido durante otros dos años. El suministro de gas finalmente se agotó y la Viking Orbiter 1 dejó de funcionar el 7 de agosto de 1980, después de 1.489 órbitas alrededor de Marte.
Los últimos datos de la sonda Viking Lander 2 llegaron a la Tierra el 11 de abril de 1980. La sonda Lander 1 realizó su última transmisión a la Tierra el 11 de noviembre de 1982. Los controladores del JPL intentaron, sin éxito, durante otros seis meses y medio recuperar el contacto con la sonda Viking Lander 1. La misión finalizó el 21 de mayo de 1983.
Con una sola excepción (los instrumentos sísmicos), los instrumentos científicos adquirieron más datos de los esperados. El sismómetro de la sonda Viking Lander 1 no funcionó después del aterrizaje y el sismómetro de la sonda Viking Lander 2 detectó solo un evento que pudo haber sido sísmico. Sin embargo, proporcionó datos sobre la velocidad del viento en el lugar de aterrizaje para complementar la información del experimento meteorológico y mostró que Marte tiene un fondo sísmico muy bajo.
Los tres experimentos de biología descubrieron una actividad química inesperada y enigmática en el suelo marciano, pero no aportaron pruebas claras de la presencia de microorganismos vivos en el suelo cercano a los lugares de aterrizaje. Según los biólogos de la misión, Marte se autoesteriliza. Creen que la combinación de la radiación ultravioleta solar que satura la superficie, la extrema sequedad del suelo y la naturaleza oxidante de la química del suelo impiden la formación de organismos vivos en el suelo marciano. La cuestión de si hubo vida en Marte en algún momento del pasado lejano sigue abierta.
Los instrumentos de cromatografía de gases y espectrómetro de masas de los módulos de aterrizaje no detectaron ningún signo de química orgánica en ninguno de los dos lugares de aterrizaje, pero sí proporcionaron un análisis preciso y definitivo de la composición de la atmósfera marciana y encontraron elementos traza no detectados anteriormente. Los espectrómetros de fluorescencia de rayos X midieron la composición elemental del suelo marciano.
La sonda Viking midió las propiedades físicas y magnéticas del suelo. A medida que descendían hacia la superficie, también midieron la composición y las propiedades físicas de la atmósfera superior marciana.
Los dos módulos de aterrizaje monitorizaron continuamente el tiempo en los lugares de aterrizaje. El tiempo en pleno verano marciano era repetitivo, pero en otras estaciones se volvía variable y más interesante. Aparecieron variaciones cíclicas en los patrones meteorológicos (probablemente el paso de ciclones y anticiclones alternos). Las temperaturas atmosféricas en el lugar de aterrizaje sur (Viking Lander 1) fueron tan altas como -14 °C (7 °F) al mediodía, y la temperatura de verano antes del amanecer fue de -77 °C (-107 °F). En contraste, las temperaturas diurnas en el lugar de aterrizaje norte (Viking Lander 2) durante las tormentas de polvo de mediados de invierno variaron tan poco como 4 °C (7 °F) algunos días. La temperatura más baja antes del amanecer fue de -120 °C (-184 °F), aproximadamente el punto de congelación del dióxido de carbono. Una fina capa de escarcha de agua cubría el suelo alrededor de Viking Lander 2 cada invierno.
La presión barométrica varía en cada lugar de aterrizaje cada seis meses, porque el dióxido de carbono, el principal componente de la atmósfera, se congela formando un inmenso casquete polar, alternativamente en cada polo. El dióxido de carbono forma una gran capa de nieve y luego se evapora de nuevo con la llegada de la primavera en cada hemisferio. Cuando el casquete polar sur era más grande, la presión media diaria observada por la Viking Lander 1 era tan baja como 6,8 milibares; en otras épocas del año era tan alta como 9,0 milibares. Las presiones en el lugar de aterrizaje de la Viking Lander 2 fueron de 7,3 y 10,8 milibares. (A modo de comparación, la presión superficial en la Tierra a nivel del mar es de unos 1.000 milibares).
Los vientos marcianos suelen soplar más lentamente de lo esperado. Los científicos habían esperado que alcanzaran velocidades de varios cientos de kilómetros por hora a partir de las tormentas de polvo globales observadas, pero ninguno de los módulos de aterrizaje registró ráfagas superiores a los 120 kilómetros por hora y las velocidades medias fueron considerablemente inferiores. No obstante, los orbitadores observaron más de una docena de pequeñas tormentas de polvo. Durante el primer verano austral se produjeron dos tormentas de polvo globales, con una diferencia de unos cuatro meses terrestres. Ambas tormentas oscurecieron el Sol en los lugares de aterrizaje durante un tiempo y ocultaron la mayor parte de la superficie del planeta a las cámaras de los orbitadores. Los fuertes vientos que provocaron las tormentas soplaron en el hemisferio sur.
Las fotografías tomadas desde los módulos de aterrizaje y los orbitadores superaron las expectativas en cuanto a calidad y calidad. El total superó las 4.500 tomadas desde los módulos de aterrizaje y las 52.000 tomadas desde los orbitadores. Los módulos de aterrizaje proporcionaron la primera mirada de cerca a la superficie, monitorearon las variaciones en la opacidad atmosférica a lo largo de varios años marcianos y determinaron el tamaño medio de los aerosoles atmosféricos. Las cámaras de los orbitadores observaron terrenos nuevos y a menudo desconcertantes y proporcionaron detalles más claros sobre características conocidas, incluidas algunas observaciones en color y estéreo. Los orbitadores de Viking cartografiaron el 97 por ciento de la superficie marciana.
Los cartografiadores térmicos infrarrojos y los detectores de agua atmosférica de los orbitadores adquirieron datos casi a diario, observando el planeta en baja y alta resolución. La enorme cantidad de datos de los dos instrumentos requerirá un tiempo considerable para el análisis y la comprensión de la meteorología global de Marte. Viking también determinó definitivamente que el manto de hielo residual del polo norte (que sobrevive al verano boreal) es hielo de agua, en lugar de dióxido de carbono congelado (hielo seco) como se creía anteriormente.
El análisis de las señales de radio de los módulos de aterrizaje y los orbitadores (incluidos los datos Doppler, de distancia y de ocultación, y la intensidad de la señal del enlace de retransmisión entre el módulo de aterrizaje y el orbitador) proporcionó una variedad de información valiosa.
Otros descubrimientos importantes de la misión Viking incluyen:
La superficie marciana es un tipo de arcilla rica en hierro que contiene una sustancia altamente oxidante que libera oxígeno cuando se moja.
La superficie no contiene moléculas orgánicas detectables a nivel de partes por mil millones: menos, de hecho, que las muestras de suelo traídas de la Luna por los astronautas del Apolo.
El nitrógeno, nunca antes detectado, es un componente significativo de la atmósfera marciana, y el enriquecimiento de los isótopos más pesados de nitrógeno y argón en relación con los isótopos más ligeros implica que la densidad atmosférica era mucho mayor que en el pasado distante.
Los cambios en la superficie marciana se producen con extrema lentitud, al menos en los lugares de aterrizaje de la sonda Viking. Durante la duración de la misión, solo se produjeron unos pocos cambios menores.
La mayor concentración de vapor de agua en la atmósfera se da cerca del borde del casquete polar norte a mediados del verano. Desde el verano hasta el otoño, la concentración máxima se desplaza hacia el ecuador, con una disminución del 30 por ciento en la abundancia máxima. En el verano austral, el planeta está seco, probablemente también como efecto de las tormentas de polvo.
La densidad de ambos satélites de Marte es baja (unos dos gramos por centímetro cúbico), lo que implica que se originaron como asteroides capturados por la gravedad de Marte. La superficie de Fobos está marcada por dos familias de estrías paralelas, probablemente fracturas causadas por un gran impacto que casi pudo haber destrozado a Fobos.
Las mediciones del tiempo de ida y vuelta de las señales de radio entre la Tierra y la sonda Viking, realizadas mientras Marte se encontraba más allá del Sol (cerca de las conjunciones solares), han determinado que el retraso de las señales es causado por el campo gravitatorio del Sol. El resultado confirma la predicción de Albert Einstein con una precisión estimada del 0,1 por ciento, veinte veces mayor que cualquier otra prueba.
La presión atmosférica varía un 30 por ciento durante el año marciano porque el dióxido de carbono se condensa y sublima en los casquetes polares.
La capa norte permanente es hielo de agua; la capa sur probablemente retiene algo de hielo de dióxido de carbono durante el verano.
El vapor de agua es relativamente abundante sólo en el extremo norte durante el verano, pero el agua subterránea (permafrost) cubre gran parte, si no todo, del planeta.
Los hemisferios norte y sur son drásticamente diferentes climáticamente, debido a las tormentas de polvo globales que se originan en el sur en verano.
In 1485, Columbus presented his plans of crossing the Atlantic to John II, King of Portugal. He proposed that the king equip three sturdy ships and grant Columbus one year's time to sail out into the Atlantic, search for a western route to the Orient, and return.
Columbus also requested he be made "Great Admiral of the Ocean", appointed governor of any and all lands he discovered, and given one-tenth of all revenue from those lands.
The king submitted Columbus' proposal to his experts, who rejected it. It was their considered opinion that Columbus' estimation of a travel distance of 2,400 miles (3,860 km) was, in fact, far too low.
In 1488, Columbus appealed to the court of Portugal once again, and once again, John II invited him to an audience. That meeting also proved unsuccessful, in part because not long afterwards Bartolomeu Dias returned to Portugal with news of his successful rounding of the southern tip of Africa (near the Cape of Good Hope). With an eastern sea route to Asia apparently at hand, King John was no longer interested in Columbus's far-fetched project.
Columbus traveled from Portugal to both Genoa and Venice, but he received encouragement from neither. Columbus had also dispatched his brother Bartholomew to the court of Henry VII of England, to inquire whether the English crown might sponsor his expedition, but also without success.
Columbus had sought an audience from the monarchs Ferdinand II of Aragon and Isabella I of Castile, who had united many kingdoms in the Iberian Peninsula by marrying, and were ruling together. On 1 May 1486, permission having been granted, Columbus presented his plans to Queen Isabella, who, in turn, referred it to a committee. After the passing of much time, the savants of Spain, like their counterparts in Portugal, replied that Columbus had grossly underestimated the distance to Asia. They pronounced the idea impractical and advised their Royal Highnesses to pass on the proposed venture.
However, to keep Columbus from taking his ideas elsewhere, and perhaps to keep their options open, the Catholic Monarchs gave him an annual allowance of 12,000 maravedis and, in 1489, furnished him with a letter ordering all cities and towns under their domain to provide him food and lodging at no cost.
After continually lobbying at the Spanish court and two years of negotiations, he finally had success in January 1492. Ferdinand and Isabella had just conquered Granada, the last Muslim stronghold on the Iberian Peninsula, and they received Columbus in Córdoba, in the Alcázar castle. Isabella turned Columbus down on the advice of her confessor, and he was leaving town by mule in despair, when Ferdinand intervened. Isabella then sent a royal guard to fetch him, and Ferdinand later claimed credit for being "the principal cause why those islands were discovered".
About half of the financing was to come from private Italian investors, whom Columbus had already lined up.
Tema anterior
,_formerly_attributed_to_Titian_(Alte_Pinakothek,_Munich).jpg)
.png)
1838 HT-81 “Am I Not A Woman & A Sister?” (Image via me)
1893 Columbian Expo Half Dollar. (Image via me)
