Walter Baade was a German-born American astronomer who classified stars into two distinct population types. Walter Baade. Photo courtesy Mt. Wilson Observatory.
Friedrichs-Gymnasium, Herford, Germany
Walter Baade first attended the Friedrichs-Gymnasium in Herford, from 1903 to 1912.
University of Göttingen, Göttingen, Lower Saxony, Germany
Baade earned his Ph.D. from the University of Göttingen in 1919.
Walter Baade in his office.
Walter Baade, photo courtesy Mt. Wilson Observatory.
Walter Baade, American Association of Variable Star Observers (AAVSO).
Walter Baade, German-born American astronomer.
1953 - 1960
Kloveniersburgwal 29, Amsterdam, Netherlands
Baad was a member of the Royal Netherlands Academy of Arts and Sciences (1953).
Baade was awarded the Gold Medal of the Royal Astronomical Society in 1954, for his observational work on galactic and extragalactic objects.
In 1955 Baade was awarded the Bruce Medal for outstanding lifetime contributions to astronomy.
Walter Baade, German-born American astronomer.
Walter Baade in the observatory.
Walter Baade`s memorial plaque.
Walter Baade in his office.
Walter Baade, photo courtesy Mt. Wilson Observatory.
Walter Baade, American Association of Variable Star Observers (AAVSO).
Walter Baade, German-born American astronomer.
Kloveniersburgwal 29, Amsterdam, Netherlands
Baad was a member of the Royal Netherlands Academy of Arts and Sciences (1953).
Memorial plaque placed on Baade’s grave in 2003.
Baade was awarded the Gold Medal of the Royal Astronomical Society in 1954, for his observational work on galactic and extragalactic objects.
In 1955 Baade was awarded the Bruce Medal for outstanding lifetime contributions to astronomy.
Friedrichs-Gymnasium, Herford, Germany
Walter Baade first attended the Friedrichs-Gymnasium in Herford, from 1903 to 1912.
University of Göttingen, Göttingen, Lower Saxony, Germany
Baade earned his Ph.D. from the University of Göttingen in 1919.
Fritz Zwicky was a Swiss astronomer. He worked most of his life at the California Institute of Technology in the United States of America, where he made many important contributions in theoretical and observational astronomy.
Richard Reinhard Emil Schorr (20 August 1867, Kassel – 21 September 1951, Badgastein, Salzburg), was a German astronomer.
Rudolph Minkowski, 1895 – 1976, German-American astronomer.
https://www.amazon.com/Experimentelle-kritische-Beitr%C3%83%C2%A4ge-Frage-sekund%C3%83%C2%A4ren/dp/B003A2JKVK/?tag=2022091-20
1907
(A summing up by one of the greatest of modern astronomers...)
A summing up by one of the greatest of modern astronomers, this book assesses the state of our knowledge of the processes of development in stars and galaxies. The author's historical introduction shows how the modern picture of the universe sprang from the pioneer work of the Hertzsprung-Russell diagram, Shapley's study of globular clusters, and Hubble's attack on the galaxies. The chapters on the classification and observation of galaxies are rich in the experience of a great observer. They lead into a description of Dr. Baade's discovery of the two stellar populations, and of the consequent revision of the period-luminosity relation, which doubled the distance scale of the universe.
https://www.amazon.com/Evolution-Stars-Galaxies-Walter-Baade/dp/0262520338/?tag=2022091-20
1975
https://www.amazon.com/Experimentelle-Sekundaren-Unterrichts-Insbesondere-Empfanglichkeit/dp/1168370558/?tag=2022091-20
2010
Wilhelm Heinrich Walter Baade was born on March 24, 1893, in Schröttinghausen, Westphalia, Germany. Baade’s father, Konrad, was a schoolteacher; he and his wife, Charlotte Wulfhorst, were Protestants and planned a career in theology for their son.
Walter Baade first attended the Friedrichs-Gymnasium in Herford, from 1903 to 1912, then he decided that astronomy appealed to him more than the church: his choice resulted in a lifetime devoted to telescopic observations that have seldom been equaled, either in technical skill or in theoretical significance. From the Gymnasium, Baade went briefly to the University of Münster, transferring to Göttingen in the Easter term of 1913. There he remained as a student throughout World War I, gaining competence in the observatory under Leopold Ambronn and serving for three years as assistant to the famous mathematician Felix Klein. Baade earned his Ph.D. at Göttingen in 1919.
During World War I Baade was exempt from active military service because of his congenitally dislocated hip, but beginning in 1917 he had to spend eight hours a day on war work, in an installation for testing airplane models.
Shortly after passing his doctoral examination in July 1919, Baade became scientific assistant to Richard Schorr, director of the University of Hamburg’s observatory at Bergedorf, located about ten miles southeast of the city. His main interest was in astrophysical problems - as shown by his dissertation, written under Johannes Hartmann, on the spectroscopic binary star β Lyrare (1921) - but his job required him to confirm the positions of many comets and asteroids. This he did conscientiously, soon discovering a comet of his own (1923) and providing an explanation for the shape of comets’ tails, published in 1927 with the first of a series of distinguished collaborators - the theoretical physicist Wolfgang Pauli, who was then a Privatdozent at Hamburg. Baade also discovered two remarkable asteroids (1920, 1949): (944) Hidalgo, which recedes farther from the sun than any other asteroid, and (1566) Icarus, noted for its close approaches both to the sun and to the earth, having passed within 4,000,000 miles of us as recently as 14 June 1968.
A meeting with Harlow Shapley in 1920 aroused Baade’s interest in globular star clusters and the pulsating variables they contain. Despite the relatively small size of his telescope, Baade began observing them and in 1926 suggested a way to prove that the radiating surface of such variable stars actually rises and falls. That same year a Rockefeller fellowship enabled him to realize his dream of visiting the big telescopes in California.
Returning to Bergedorf in 1927, Baade was promoted to observer, but got no action on his plea that their 39-inch telescope be moved to a more favorable site. He turned down a job offered him at Jena, because it provided even less in the way of good observing facilities, and became a Privatdozent at Hamburg in 1928. In 1929 he went to the Philippine Islands to observe a total solar eclipse on 9 May. Clouds covered the sun during the crucial time, but the long sea voyage served to cement his friendship with the Estonian Bernard Voldemar Schmidt, who at Baadeʿs urging designed the optical system used in the Schmidt wide-angle telescopes.
The year 1931 brought Baade an invitation to join the staff at Mt. Wilson Observatory near Pasadena, California; he accepted immediately, resigning his position at Hamburg and moving to the clearer skies and larger instruments in California as to the Promised Land. When his friend Rudolf Minkowski was forced to resign his professorship at Hamburg in 1933, Baade helped him to emigrate, thus enabling the two men to continue in California an already productive collaboration.
Now that Baade had realized his dream of working with the best telescopes in the world, he made the most of it. With Minkowski, he continued spectroscopic work begun in Germany (1937), and with Edwin Powell Hubble he studied distant galaxies (1938). His work with Fritz Zwicky on supernovae (1938) led to papers on the Crab Nebula (1942) and on Nova Ophiuchi 1604 (1943).
When the United States entered World War II, Baade was classified as an enemy alien, but this favored rather than hampered his astronomical career: with many astronomers engaged in war work, and the lights of Los Angeles dimmed to protect coastal shipping, Baade had increased access to the telescopes and the added advantage of darker skies. Under these favorable circumstances, he was able to photograph stars in the hitherto unresolved inner portions of the Andromeda galaxy, M31, and in both of its satellite galaxies, M32 and NGC205 (1944). This achievement was both technically difficult - thought, indeed to be unattainable with the 100-inch telescope he used - and theoretically significant, because the brightest stars in the nucleus of M31 turned out to be red - not blue, as in the surrounding spiral arms. Baade realized he was dealing with two different stellar populations, which he called Type I (found in dusty regions, brightest stars blue) and Type II (found in dust-free regions, brightest stars red).
At a ceremony dedicating the 200-inch Palomar telescope on 1 July 1948, Baade outlined the ways he thought this great new instrument should be used to explore the universe. He suggested that since distance measurements depend critically on a reliable standard sequence of stellar magnitudes, the first thing to do was to replace the North Polar Sequence with a better one based on photoelectric techniques. His concern with distance criteria soon had spectacular results in another way, when he looked for cluster-type variables in the Andromeda galaxy. At the accepted distance of 750,000 light-years, these stars should have appeared in photographs taken with the 200-inch telescope; when they did not, Baade reasoned correctly that the galaxy was more distant than had previously been thought. Announced in 1952 at the Rome meeting of the International Astronomical Union, this conclusion cleared up several inconsistencies, but also essentially doubled the size of the universe. At a symposium on stellar evolution held during that same meeting, Baade presented colormagnitude diagrams for star clusters that his young collaborators Halton C. Arp, William A. Baum, and Allan R. Sandage had just completed, in support of his theory that Type I stars are younger - on a cosmological time scale - than Type II stars. This was an oversimplification, as suggested by Boris V. Kukarkin during the ensuing discussion, but it represented a major step toward today’s understanding of the life cycles of stars.
Baade left his mark on yet another aspect of astronomy when he identified, in photographs he had taken with the 200-inch telescope, several objects first detected by radiotelescopes (1954). One of them, the radio source Cygnus A, had a twinned appearance: Baade correctly placed it far outside our galaxy - which seemed unbelievable - but his conclusion, based on theoretical work done in 1950 with Lyman Spitzer, Jr., that it represented two galaxies in collision, has not stood the test of time. In a final contribution to the understanding of objects later called quasars, Baade showed that a jet issuing from the galaxy M87 emitted strongly polarized light (1956).
Upon his retirement in 1958, Baade gave a series of lectures at Harvard University (published as Evolution of Stars and Galaxies), and then spent six months in Australia, where he used the 74-inch telescope at Mt. Stromlo near Canberra, before returning to Göttingen as Gauss professor. An operation on his hip and six months’ convalescence in bed preceded his death from respiratory failure. He died on June 25, 1960, in Göttingen, West Germany.
Much of his work remained unpublished - in some cases because he was dissatisfied with it, in others because he preferred active research to the tedious job of writing about it - but of what did appear, the British astronomer Fred Hoyle has commented: “Almost every one of Baade’s papers turned out to have far-reaching consequences.”
Baade's chief achievement was in his successful study of star groupings in various systems. He showed that spiral galaxies contained generally hot blue stars and elliptical galaxies mainly cooler red ones. Using a 100-inch telescope, he resolved the Andromeda galaxy (Earth's nearest major galaxy) into discrete stars. He also identified several cosmic radio sources optically, using the 200 inch Mount Palomar telescope.
Together with Fritz Zwicky, Baade identified supernovae as a new category of astronomical objects. Zwicky and he also proposed the existence of neutron stars and proposed that supernovae could create neutron stars.
Beginning in 1952 he and Rudolph Minkowski identified the optical counterparts of various radio sources, including Cygnus A. He discovered 10 asteroids, including 944 Hidalgo (long orbital period) and the Apollo-class asteroid 1566 Icarus (the perihelion of which is closer than that of Mercury) and the Amor asteroid 1036 Ganymed.
Baade received some honors during his lifetime. He was awarded the Gold Medal of the Royal Astronomical Society in 1954, for his observational work on galactic and extragalactic objects, and in 1955 received the Bruce Medal of the Astronomical Society of the Pacific. He was a member of the American Philosophical Society, and of scientific academies in Amsterdam, Göttingen, Lund, Munich, and Mainz.
There are a number of celestial bodies that were named in his honor as follows: Asteroid 1501 Baade, the crater Baade on the Moon, Vallis Baade, a vallis (valley) on the Moon, the asteroid 966 Muschi, after his wife's nickname.
(A summing up by one of the greatest of modern astronomers...)
1975(The resolution of Messier 32, NGC 205, and the central re...)
1944Baade’s parents were convinced Protestants and planned a career in theology for their son.
Baad was a member of the Royal Netherlands Academy of Arts and Sciences (1953).
Physical Characteristics: Baade had congenitally dislocated hip, and for that reason he was exempt from active military service during World War I.
Quotes from others about the person
"Dr. Walter Baade of Mount Wilson Observatory facetiously accused the present generation of Milky Way astronomers of not having looked sufficiently far beyond our “local swimming hole”." — Bart J. Bok.
"[Walter] Baade, like all scientists of substance, had a set view of how things were put together, to be sure a view to be always challenged by the scientist himself, but defended as well against all less informed mortals who objected without simon-pure reasons." — Allan Rex Sandage.
In 1929 Walter Baade married Johanna Bohlmann.
Baad worked on the subject of an explanation for the shape of comets’ tails, published in 1927 with the first of a series of distinguished collaborators including Pauli.
A meeting with Harlow Shapley in 1920 aroused Baade’s interest in globular star clusters and the pulsating variables they contain.
Together with Fritz Zwicky, Baade identified supernovae as a new category of astronomical objects.
In 1919 Baad worked as an assistant to Richard Schorr, director of the University of Hamburg’s observatory at Bergedorf.
When his friend Rudolf Minkowski was forced to resign his professorship at Hamburg in 1933, Baade helped him to emigrate, thus enabling the two men to continue in California an already productive collaboration.
