On this day:
1781 – William Herschel discovers Uranus.
Frederick William Herschel, KH, FRS (German: Friedrich Wilhelm Herschel; 15 November 1738 – 25 August 1822) was a British astronomer and composer of German origin, and brother of fellow astronomer Caroline Herschel, with whom he worked. Born in the Electorate of Hanover, Herschel followed his father into the Military Band of Hanover, before migrating to Great Britain in 1757 at the age of nineteen.
Herschel constructed his first large telescope in 1774, after which he spent nine years carrying out sky surveys to investigate double stars. The resolving power of the Herschel telescopes revealed that the nebulae in the Messier catalogue were clusters of stars. Herschel published catalogues of nebulae in 1802 (2,500 objects) and in 1820 (5,000 objects). In the course of an observation on 13 March 1781, he realized that one celestial body he had observed was not a star, but a planet, Uranus. This was the first planet to be discovered since antiquity and Herschel became famous overnight. As a result of this discovery, George III appointed him Court Astronomer. He was elected as a Fellow of the Royal Society and grants were provided for the construction of new telescopes.
Herschel pioneered the use of astronomical spectrophotometry as a diagnostic tool, using prisms and temperature measuring equipment to measure the wavelength distribution of stellar spectra. Other work included an improved determination of the rotation period of Mars, the discovery that the Martian polar caps vary seasonally, the discovery of Titania and Oberon (moons of Uranus) and Enceladus and Mimas (moons of Saturn). In addition, Herschel discovered infrared radiation. Herschel was made a Knight of the Royal Guelphic Order in 1816. He was the first President of the Royal Astronomical Society when it was founded in 1820. He died in August 1822, and his work was continued by his only son, John Herschel.
Early life and musical activities
Herschel was born in the Electorate of Hanover in Germany, then part of the Holy Roman Empire, one of ten children of Isaac Herschel by his marriage to Anna Ilse Moritzen. His family were Lutheran Christians. His father was an oboist in the Hanover Military Band. In 1755 the Hanoverian Guards regiment, in whose band Wilhelm and his brother Jakob were engaged as oboists, was ordered to England. At the time the crowns of Great Britain and Hanover were united under King George II. As the threat of war with France loomed, the Hanoverian Guards were recalled from England to defend Hanover. After they were defeated at the Battle of Hastenbeck, Herschel’s father Isaak sent his two sons to seek refuge in England in late 1757. Although his older brother Jakob had received his dismissal from the Hanoverian Guards, Wilhelm was accused of desertion (for which he was pardoned by George III in 1782). Wilhelm, nineteen years old at this time, was a quick student of the English language. In England he went by the English rendition of his name, Frederick William Herschel.
In addition to the oboe, he played the violin and harpsichord and later the organ. He composed numerous musical works, including 24 symphonies and many concertos, as well as some church music. Six of his symphonies were recorded in April 2002 by the London Mozart Players, conducted by Matthias Bamert (Chandos 10048).
Herschel moved to Sunderland in 1761 when Charles Avison immediately engaged him as first violin and soloist for his Newcastle orchestra, where he played for one season. In ‘Sunderland in the County of Durh: apprill [sic] 20th 1761’ he wrote his Symphony No. 8 in C Minor. He was head of the Durham Militia band 1760–61 and visited the home of Sir Ralph Milbanke at Halnaby Hall in 1760, where he wrote two symphonies, as well as giving performances himself.
After Newcastle he moved to Leeds and Halifax where he was the first organist at St John the Baptist church (now Halifax Minster). He became organist of the Octagon Chapel, Bath, a fashionable chapel in a well-known spa, in which city he was also Director of Public Concerts. He was appointed as the organist in 1766 and gave his introductory concert on 1 January 1767. As the organ was still incomplete, he showed off his versatility by performing his own compositions including a violin concerto, an oboe concerto and a harpsichord sonata. The organ was completed in October 1767. His sister Caroline came to England in 1772 and lived with him there in New King Street, Bath. The house they shared is now the location of the Herschel Museum of Astronomy. His brothers Dietrich, Alexander and Jakob (1734–1792) also appeared as musicians of Bath. In 1780, Herschel was appointed director of the Bath orchestra, with his sister often appearing as soprano soloist.
Herschel’s music led him to make the acquaintance of an amateur violinist, the Rev. John Michell of Thornhill, a former leading Cambridge mathematics professor who was already noted as England’s leading geologist and was developing groundbreaking views on astronomy and the construction of telescopes. Michell sparked Herschel’s interest in mathematics and lenses. Michell was later (1783) to publish work on ‘dark stars’ (black holes). After Michell’s death in 1793, Herschel bought a ten foot long, 30-inch reflecting telescope from Michell’s estate which he had to reconstruct due to damage in transport.
His interest in astronomy grew stronger after he made the acquaintance of the English Astronomer Royal Nevil Maskelyne. He started building his own reflecting telescopes and would spend up to 16 hours a day grinding and polishing the speculum metal primary mirrors. He “began to look at the planets and the stars” in May 1773 and on 1 March 1774 began an astronomical journal by noting his observations of Saturn’s rings and the Great Orion Nebula (M 42).
Herschel’s early observational work soon focused on the search for pairs of stars that were very close together visually. Astronomers of the era expected that changes over time in the apparent separation and relative location of these stars would provide evidence for both the proper motion of stars and, by means of parallax shifts in their separation, for the distance of stars from the Earth. The latter was a method first suggested by Galileo Galilei. From the back garden of his house in New King Street, Bath, and using a 6.2-inch aperture (160 mm), 7-foot focal length (2.1 m) (f/13) Newtonian telescope “with a most capital speculum” of his own manufacture, in October 1779, Herschel began a systematic search for such stars among “every star in the Heavens”, with new discoveries listed through 1792. He soon discovered many more binary and multiple stars than expected, and compiled them with careful measurements of their relative positions in two catalogues presented to the Royal Society in London in 1782 (269 double or multiple systems) and 1784 (434 systems). A third catalogue of discoveries made after 1783 was published in 1821 (145 systems).
In 1797, Herschel measured many of the systems again, and discovered changes in their relative positions that could not be attributed to the parallax caused by the Earth’s orbit. He waited until 1802 (in Catalogue of 500 new Nebulae, nebulous Stars, planetary Nebulae, and Clusters of Stars; with Remarks on the Construction of the Heavens) to announce the hypothesis that the two stars might be “binary sidereal systems” orbiting under mutual gravitational attraction, a hypothesis he confirmed in 1803 in his Account of the Changes that have happened, during the last Twenty-five Years, in the relative Situation of Double-stars; with an Investigation of the Cause to which they are owing. In all, Herschel discovered over 800 confirmed double or multiple star systems, almost all of them physical rather than optical pairs. His theoretical and observational work provided the foundation for modern binary star astronomy; new catalogues adding to his work were not published until after 1820 by Friedrich Wilhelm Struve, James South and John Herschel.
In March 1781, during his search for double stars, Herschel noticed an object appearing as a disk. Herschel originally thought it was a comet or a stellar disk, which he believed he might actually resolve. He made many more observations of it, and afterwards Russian Academician Anders Lexell computed the orbit and found it to be probably planetary. Herschel agreed, determining that it must be a planet beyond the orbit of Saturn. He called the new planet the ‘Georgian star’ (Georgium sidus) after King George III, which also brought him favour; the name did not stick. In France, where reference to the British king was to be avoided if possible, the planet was known as ‘Herschel’ until the name ‘Uranus’ was universally adopted. The same year, Herschel was awarded the Copley Medal and elected a Fellow of the Royal Society. In 1782, he was appointed “The King’s Astronomer” (not to be confused with the Astronomer Royal). He and his sister subsequently moved to Datchet (then in Buckinghamshire but now in Berkshire) on 1 August 1782. He continued his work as a telescope maker and achieved an international reputation for their manufacture, profitably selling over 60 completed reflectors to British and Continental astronomers.
Deep sky surveys
From 1782 to 1802, and most intensively from 1783 to 1790, Herschel conducted systematic surveys in search of “deep sky” or nonstellar objects with two 20-foot focal length (610 cm), 12-inch aperture (30 cm) and 18.7-inch aperture (47 cm) telescopes (in combination with his favoured 6-inch aperture instrument). Excluding duplicated and “lost” entries, Herschel ultimately discovered over 2400 objects defined by him as nebulae. (At that time, nebula was the generic term for any visually diffuse astronomical object, including galaxies beyond the Milky Way, until galaxies were confirmed as extragalactic systems by Edwin Hubble in 1924.)
Herschel published his discoveries as three catalogues: Catalogue of One Thousand New Nebulae and Clusters of Stars (1786), Catalogue of a Second Thousand New Nebulae and Clusters of Stars (1789) and the previously cited Catalogue of 500 New Nebulae … (1802). He arranged his discoveries under eight “classes”: (I) bright nebulae, (II) faint nebulae, (III) very faint nebulae, (IV) planetary nebulae, (V) very large nebulae, (VI) very compressed and rich clusters of stars, (VII) compressed clusters of small and large [faint and bright] stars, and (VIII) coarsely scattered clusters of stars. Herschel’s discoveries were supplemented by those of Caroline Herschel (11 objects) and his son John Herschel (1754 objects) and published by him as General Catalogue of Nebulae and Clusters in 1864. This catalogue was later edited by John Dreyer, supplemented with discoveries by many other 19th century astronomers, and published in 1888 as the New General Catalogue (abbreviated NGC) of 7840 deep sky objects. The NGC numbering is still the most commonly used identifying label for these celestial landmarks.
Work with his sister Caroline
Following the death of their father, William suggested that Caroline join him in Bath, England. In 1772, Caroline was first introduced to astronomy by her brother.
Caroline spent many hours polishing the mirrors of high performance telescopes so that the amount of light captured was maximized. She also copied astronomical catalogues and other publications for William. After William accepted the office of King’s Astronomer to George III, Caroline became his constant assistant.
In October 1783, a new 20-foot telescope came into service for William. During this time, William was attempting to observe and then record all of the observations. He had to run inside and let his eyes readjust to the artificial light before he could record anything, and then he would have to wait until his eyes were adjusted to the dark before he could observe again. Caroline became his recorder by sitting at a desk near an open window. William would shout out his observations and she would write them down along with any information he needed from a reference book.
In 1783, he gave Caroline a telescope, and she began to make astronomical discoveries in her own right, particularly comets. Between 1783 and 1787, she made an independent discovery of M110 (NGC 205), which is the second companion of the Andromeda Galaxy. During the years 1786-1797, she discovered or observed eight comets, eleven nebulae and, at her brother’s suggestion, updated and corrected Flamsteed’s work detailing the position of stars. Her eight comets were published between 28 August 1782 to 5 February 1787. Five of her comets were published in Philosophical Transactions of the Royal Society. William was even summoned to Windsor Castle to demonstrate Caroline’s comet to the royal family. William recorded this phenomenon himself, terming it “My Sister’s Comet.” She wrote letters to the Astronomer Royal to announce the discovery of her second comet, and wrote to Joseph Banks upon the discovery of her third and fourth comets. Flamsteed’s work was published as the British Catalogue of Stars. The catalogue contained an index of more than 560 stars that had not been previously included. She also rediscovered Comet Encke in 1795. She was honoured by the Royal Astronomical Society for this work in 1828. Caroline also continued to serve as his assistant, often taking notes while he observed at the telescope.
For her work as William’s assistant, she was granted an annual salary of £50 (equivalent to £5,700 in 2016) by George III. Her appointment made her the first female in England to be honored with a government position.
In June 1785, owing to damp conditions, he and Caroline moved to Clay Hall in Old Windsor. In 1786, the Herschels moved to a new residence on Windsor Road in Slough. He lived the rest of his life in this residence, which came to be known as Observatory House. It is no longer standing.
On 8 May 1788, he married the widow Mary Pitt (née Baldwin) at St Laurence’s Church, Upton in Slough. The marriage caused a lot of tension in the brother-sister relationship. Caroline has been referred to as a bitter, jealous woman who worshiped her brother and resented her sister-in-law for invading her domestic life. With the arrival of Mary, Caroline lost her managerial and social responsibilities in the household. Caroline destroyed her journals between the years 1788 to 1798, so her feelings during this period are not entirely known. According to her memoir, Caroline then moved to separate lodgings, but continued to work as her brother’s assistant. When her brother and his family were away from their home, she would often return to take care of it for them. In later life, Caroline and Lady Herschel exchanged affectionate letters.
Caroline continued to work on her astronomical work, even after William’s death in 1822. She worked to verify and confirm his findings as well as putting together catalogues of nebulae. Towards the end of her life, she arranged two-and-a-half thousand nebulae and star clusters into zones of similar polar distances. She did this so that her nephew, John, could re-examine them systematically. Eventually, this list was enlarged and renamed the New General Catalogue. In 1828, she was awarded the Royal Astronomical Society’s Gold Medal for her work.
During his career, he constructed more than four hundred telescopes. The largest and most famous of these was a reflecting telescope with a 49 1⁄2-inch-diameter (1.26 m) primary mirror and a 40-foot (12 m) focal length. Because of the poor reflectivity of the speculum mirrors of that day, Herschel eliminated the small diagonal mirror of a standard newtonian reflector from his design and tilted his primary mirror so he could view the formed image directly. This design has come to be called the Herschelian telescope. In 1789, shortly after this instrument was operational, he discovered a new moon of Saturn: Mimas, only 250 miles in diameter. A second moon followed within the first month of observation. The “40-foot telescope” proved very cumbersome, and most of his observations were done with a smaller 18.5-inch (47 cm) 20-foot-focal-length (6.1 m) reflector. Herschel discovered that unfilled telescope apertures can be used to obtain high angular resolution, something which became the essential basis for interferometric imaging in astronomy (in particular Aperture Masking Interferometry and hypertelescopes).
Reconstruction of the 20ft telescope
In 2012, the BBC Stargazing Live television programme built a replica of the 20-foot telescope using Herschel’s original plans but modern materials. It is to be considered a close modern approximation rather than an exact replica. A modern glass mirror was used, the frame uses metal scaffolding and the tube is a sewer pipe. The telescope was shown on the programme in January 2013 and stands on the Art, Design and Technology campus of the University of Derby where it will be used for educational purposes.
Life on other celestial bodies
Herschel was sure that he had found ample evidence of life on the Moon and compared it to the English countryside. He did not refrain himself from theorising that the other planets were populated, with a special interest in Mars, which was in line with most of his contemporary scientists. At Herschel’s time, scientists tended to believe in a plurality of civilised worlds; in contrast, most religious thinkers referred to unique properties of the earth.  Herschel went so far to speculate that the interior of the sun was populated.
Sunspots, climate, and wheat yields
Herschel started to examine the correlation of solar variation and solar cycle and climate. Over a period of 40 years (1779–1818), Herschel had regularly observed sunspots and their variations in number, form and size. Most of his observations took place in a period of low solar activity, the Dalton minimum, when sunspots were relatively few in number. This was one of the reasons why Herschel was not able to identify the standard 11-year period in solar activity. Herschel compared his observations with the series of wheat prices published by Adam Smith in The Wealth of Nations.
In 1801, Herschel reported his findings to the Royal Society and indicated five prolonged periods of few sunspots correlated with the price of wheat. Herschel’s study was ridiculed by some of his contemporaries but did initiate further attempts to find a correlation. Later in the 19th century, William Stanley Jevons proposed the 11-year cycle with Herschel’s basic idea of a correlation between the low amount of sunspots and lower yields explaining recurring booms and slumps in the economy. Herschel’s speculation on a connection between sunspots and regional climate, using the market price of wheat as a proxy, continues to be cited.
According to one study, the influence of solar activity can actually be seen on the historical wheat market in England over ten solar cycles between 1600 and 1700. The evaluation is controversial and the significance of the correlation is doubted by some scientists.
Planets discovered: 1 Uranus 13 March 1781
Moons discovered: 4 Oberon 11 January 1787
Titania 11 January 1787
Enceladus 28 August 1789
Mimas 17 September 1789
In his later career, Herschel discovered two moons of Saturn, Mimas and Enceladus; as well as two moons of Uranus, Titania and Oberon. He did not give these moons their names; they were named by his son John in 1847 and 1852, respectively, after his death. Herschel measured the axial tilt of Mars and discovered that the martian ice caps, first observed by Giovanni Domenico Cassini (1666) and Christiaan Huygens (1672), changed size with that planet’s seasons. It has been suggested that Herschel might have discovered rings around Uranus.
Herschel introduced but did not create the word “asteroid”, meaning star-like (from the Greek asteroeides, aster “star” + -eidos “form, shape”), in 1802 (shortly after Olbers discovered the second minor planet, 2 Pallas, in late March), to describe the star-like appearance of the small moons of the giant planets and of the minor planets; the planets all show discs, by comparison. By the 1850s ‘asteroid’ became a standard term for describing certain minor planets.
From studying the proper motion of stars, Herschel was the first to realize that the solar system is moving through space, and he determined the approximate direction of that movement. He also studied the structure of the Milky Way and concluded that it was in the shape of a disk. He incorrectly assumed the sun was in the centre of the disc, a theory known as Galactocentrism, which was eventually corrected by the findings of Harlow Shapley in 1918.
Discovery of infrared radiation in sunlight
On 11 February 1800, Herschel was testing filters for the sun so he could observe sun spots. When using a red filter he found there was a lot of heat produced. Herschel discovered infrared radiation in sunlight by passing it through a prism and holding a thermometer just beyond the red end of the visible spectrum. This thermometer was meant to be a control to measure the ambient air temperature in the room. He was shocked when it showed a higher temperature than the visible spectrum. Further experimentation led to Herschel’s conclusion that there must be an invisible form of light beyond the visible spectrum.
Herschel used a microscope to establish that coral was not a plant–as many at the time believed–because it lacked the cell walls characteristic of plants.
Family and death
William Herschel and Mary had one child, John, born at Observatory House on 7 March 1792. William’s personal background and rise as man of science had a profound impact on the upbringing of his son and grandchildren. He was elected a Foreign Honorary Member of the American Academy of Arts and Sciences in 1788. In 1816, William was made a Knight of the Royal Guelphic Order by the Prince Regent and was accorded the honorary title ‘Sir’ although this was not the equivalent of an official British knighthood. He helped to found the Astronomical Society of London in 1820, which in 1831 received a royal charter and became the Royal Astronomical Society. In 1813, he was elected a foreign member of the Royal Swedish Academy of Sciences.
On 25 August 1822, Herschel died at Observatory House, Windsor Road, Slough, and was buried at nearby St Laurence’s Church, Upton, Slough. Herschel’s epitaph is
“ Coelorum perrupit claustra
(He broke through the barriers of the heavens) ”
Herschel’s son John Herschel also became a famous astronomer. One of William’s brothers, Alexander Herschel, moved permanently to England, near his sister Caroline and nephew John. Caroline returned to Hanover after the death of her brother. She died on 9 January 1848.
His house at 19 New King Street in Bath, Somerset, where he made many telescopes and first observed Uranus, is now home to the Herschel Museum of Astronomy.
William Herschel lived most of his life in Slough, a town then in Buckinghamshire. He died in the town and was buried under the tower of the Church of St Laurence, Upton-cum-Chalvey, near Slough. Herschel is quite respected in the town and there are several memorials to him and his discoveries. In 2011 a new bus station, the design of which was inspired by the infrared experiment of William Herschel, was built in the centre of Slough.
Born on this day:
1908 – Myrtle Bachelder, American chemist and Women’s Army Corps officer (d. 1997)
Myrtle Claire Bachelder (March 13, 1908 – May 22, 1997) was an American chemist and Women’s Army Corps officer, who is noted for her secret work on the Manhattan Project atomic bomb program, and for the development of techniques in the chemistry of metals.
Early life and career
Myrtle C. Bachelder was born on March 13, 1908 in Orange, Massachusetts. She earned a bachelor of science degree from Middlebury College in 1930, and became a high school science teacher and athletics coach in South Hadley Falls, Massachusetts. She received her master of education degree from Boston University.
World War II: the atomic bomb
During World War II, Bachelder enlisted in the Women’s Army Corps (WAC) in November 1942, at the Springfield, Massachusetts headquarters. After spending time in training at military bases in several U.S. states, she received orders assigning her to the Company ‘D’ WAC Detachment of the Manhattan District, United States Army Corps of Engineers. Her secret assignment was to lead a group of 15 to 20 women from the WAC, stationed in Des Moines, Iowa, to Fort Sill, Oklahoma, and from there to Santa Fe, New Mexico. She and the women under her command arrived at Los Alamos, New Mexico on October 21, 1943.
“Manhattan” was the code name for the special military division dedicated to developing an atomic weapon. In the clandestine laboratory at the remote Los Alamos desert site, Bachelder was responsible for the analysis of the spectroscopy of uranium isotopes. Since the uranium-235 isotope is fissile, whereas the uranium-238 isotope is not, Bachelder’s role in the project was a crucial task: to ensure the purity of the sub-critical material, and therefore the nuclear explosion, of the world’s first atomic bombs.
Bachelder (center) at Los Alamos in 1946, with Captain Arlene Scheidenhelm, Director of WAC, Manhattan District (left), and First Lieutenant Marguerite Carrera, Commanding Officer, WAC Los Alamos detachment (right)
These methods were used during the preparation of plutonium-239, the fissile material used in the construction of the atomic bomb for the Trinity nuclear test, on July 16, 1945. Analogous methods were used for the uranium weapon, code-named “Little Boy”, which destroyed Hiroshima, Japan on August 6, 1945, and for the plutonium bomb which destroyed Nagasaki, Japan on August 9, 1945, leading to the Japanese surrender. The secret program was under the general direction of J. Robert Oppenheimer, whom Bachelder described as:
A “pencil and paper man”, immersed in physics theory, who was more than a little amazed by the Los Alamos lab machinery. Bachelder recalled Oppenheimer standing in front of her lab’s most important and expensive instrument punching buttons at random … He asked “What does this do?” Then he’d punch another button … He might have wrecked the machine if he hadn’t finally been persuaded to leave it alone.
Contribution to post-war developments in nuclear energy
The conclusion of the Second World War was also the dawning of a new “Atomic Age”, in which the peacetime potential of nuclear energy began to be explored. Bachelder was among the scientists who opposed the May-Johnson Bill of October 1945, a Congressional bill proposed by the Interim Committee, which would have maintained military control over nuclear research. The bill was defeated in Congress and superseded by the McMahon Atomic Energy Act. In January 1947, the newly formed Atomic Energy Commission approved the declassification of 270 previously secret documents. These included discoveries related to X-radiation and purification of uranium ores, which had been made by Bachelder during the course of the war effort. At this time, the rarity and importance of Bachelder’s achievements as a woman in science were also acknowledged.
Scientific research and later career
After leaving the Army, Bachelder became a research chemist at the University of Chicago, where the first self-sustaining nuclear reaction had been achieved in 1942. Nobel Laureate James Franck had been Director of the Chemistry Division of the Metallurgical Laboratory during the earlier phases of the Manhattan Project. Bachelder joined the University’s Institute for the Study of Metals (renamed as the James Franck Institute in 1967), and she conducted further research in metallochemistry.
Among other achievements, Bachelder developed methods for the purification of the rare elements tellurium and indium. Other aspects of her broad scientific expertise found application in the field of marine archaeology, when she determined the chemical composition of brass cannons found in the Aegean Sea on sunken ships. She also made contributions to astrochemistry, when NASA asked her to analyze the chemistry of Moon rocks which had been collected from the Moon’s surface during the Apollo missions from 1969 to 1972.
Bachelder retired from the Franck Institute in 1973, and was subsequently active as an official of the American Association of Retired Persons (AARP). She died in Chicago on May 22, 1997.
Bachelder believed that her role in the development of the atomic bomb, and the subsequent use of atomic weapons against Japan, had been justified, in order to end the Second World War, and to avoid greater loss of life that would have been entailed, in a U.S. land invasion and extended conflict with Japan. Later in life, during the period of the Strategic Arms Limitation Talks, Bachelder stated that, although she supported nuclear arms control:
Opponents of nuclear weapons should resist the urge to take the 1940s bomb-building effort out of its proper historical context — “One cannot pull that activity out of that time, set it down in the 1980s, and pass judgement.”
Delancey Place: The beach boys’ abusive father
“‘My dad was an asshole,’ Dennis said, ‘and he treated us like shit, and his punishments were sick. But you played a tune for him and he was a marshmallow. This mean motherf*cker would cry with bliss, like the lion in The Wizard of Oz, when he heard the music.’ If music can soothe the savage beast, the Wilson children learned to make music at an early age.”