'''Donald Howard Menzel''' (* 11. April 1901, † 14. Dezember 1976) war ein US-amerikanischer Astronom.

Menzel studierte an der Universität von Denver und erwarb seinen Ph.D. anschließend an der Princeton University. Er arbeitete am Lick Observatorium bis er 1932 eine Stellung an der Harvard University annahm. Von 1954 bis 1956 war er Präsident der American Astronomical Society.

Menzel arbeitete zunächst auf dem Gebiet der planetarischen Nebeln formulierte er zusammen mit Lawrence Aller und James Baker.

Er schrieb u.a. "A Field Guide to the Stars and Planets", Teil der "Peterson Field Guides". Neben seiner wissenschaftlicher Tätigkeit gehörte Menzel auch zu den Astronomen, die Berichte über angebliche UFO-Sichtungen immer wieder hinterfragten.
Er beschäftigte sich in 3 Büchern mit der Problematik: "Flying Saucers" (1953), "The World Of Flying Saucers: A Scientific Examination of a Major Myth of the Space Age" (1963) und "The UFO Enigma: The Definitive Explanation of the UFO Phenomenon" (1977).
Menzel erklärte 1968 vor dem U.S. House Committee on Science and Astronautics, alle UFO-Sichtungen seien durch natürliche Phänoneme zu erklären.

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|death_date        = December 14 1976
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	'''Donald Howard Menzel''' (astrophysicist. 

He was one of the leading astronomers of his era, and also earned notoriety as an early skeptic of UFOs as an extraordinary phenomenon. 

==Biography==
Born in Florence, Colorado, Menzel demonstrated a precocious intellect: before beginning kindergarten he had not only learned to read but had also learned morse code.

At 16 years old, Menzel enrolled at the University of Colorado to study chemistry. However, observing a solar eclipse in 1918 led him to change his course of study to astronomy. Menzel earned an internship at Princeton University, and spent summer vacations at Harvard University as a research assistant to Harlow Shapley. 

Menzel studied at the Princeton.  After earning his Ph.D. in 1924, Menzel taught at the Harvard.  From 1954-56 he was President of the American Astronomical Society. From 1964 to his death, Menzel was a U.S. State Department consultant for Latin American affairs.

He began teaching at Harvard in 1932, and earned full professorship in 1938; in 1952 he was appointed acting director of the Harvard Observatory, and was the full director from 1954 to 1966, when the observatory became an international center of radio astronomy. He retired from Harvard in 1971. 

Menzel initially performed solar research, but later concentrated on studying gaseous nebulae.  His work with Lawrence Aller and James Gilbert Baker defined many of the fundamental principles of the study of planetary nebulae.

He wrote ''A Field Guide to the Stars and Planets'', part of the Peterson Field Guides.

==Menzel and UFOs==
In addition to his academic and popular contributions to the field of debunking UFOs: ''Flying Saucers (book)'' (1953), ''The World Of Flying Saucers: A Scientific Examination of a Major Myth of the Space Age'' (1963), and ''The UFO Enigma: The Definitive Explanation of the UFO Phenomenon'' (1977). All of Menzel's UFO books argued that UFOs were nothing more than misidentification of prosaic phenomena such as stars, clouds and airplanes; or the result of people seeing unusual atmospheric phenomena they were unfamiliar with. He often suggested that atmospheric hazes or temperature inversions could distort stars or planets, and make them appear to be larger than in reality, unusual in their shape, and in motion. In 1968, Menzel testified before the U.S. House Committee on Science and Astronautics - Symposium on UFOs, stating that he considered all UFO sightings to have natural explanations.

He was perhaps the first prominent scientist to offer his opinion on the matter, and his stature doubtless influenced the mainstream and academic response to the subject. 

Perhaps Menzel's earliest public involvement in UFO matters was his appearance on a radio documentary directed and narrated by Edward R. Murrow in mid-1950. (Swords, 98)

J. Richard Greenwell wrote, "[m]ost UFO advocates considered him an 'archenemy.' Many of his [UFO] explanations were, in fact, reasonable, and Menzel certainly had the technical background to evaluate such data. However, he rarely conducted field checks and limited himself to more theoretical explanations, which, however unlikely, he considered to be more probable than extraterrestrial visitation. He accepted the probability of many technologically advanced civilizations throughout the galaxy, but not that they could easily, and routinely, travel across interstellar distances to earth." (Greenwell, 229)

===Criticism of Menzel's UFO research===
Some observers have argued that Menzel's UFO works are lacking. Atmospheric physicist and UFO researcher James E. McDonald used the word "Menzelian" to describe the astronomer's approach to UFOs (which McDonald judged inadequate, dismissive and superficial). Sociologist Ron Westrum writes, "The paradox is that his UFO books represent quite shoddy science, in contrast to his better-known work in astrophysics." (Westrum, p 34) Westrum suggests that despite Menzel's "shoddy" UFO studies, "thanks to a type of halo effect, Menzel's reputation in astronomy buttressed his loosely put together scientific arguments." (Westrum, p. 35)

Criticism also came from many scientists associated with the U.S. Air Force: Captain Edward J. Ruppelt, the first head of the UFO investigation Project Blue Book, wrote: 

:The one [UFO explanation] that received the most publicity was the one offered by Dr. Donald Menzel of Harvard University. Dr. Menzel, writing in ''Time'', ''Look'', and later in his ''Flying Saucers'', claimed that all UFO reports could be explained as various types of light phenomena. We studied this theory thoroughly because it did seem to have merit. Project Bear's physicists studied it. ATIC's scientific consultants studied it and discussed it with several leading European physicists whose specialty was atmospheric physics. In general the comments that Project Blue Book received were, "[Menzel has]  given the subject some thought but his explanations are not the panacea."<ref>Ruppelt, Edward J., ''The Report of Unidentified Flying Objects'', Garden City: Doubleday & Co., 1956</ref> 

Menzel's critics also report that his UFO theories were literally laughable. He was an occasional consultant to the University of Colorado. Boulder. Mary Lou [Armstrong, the Committee's executive assistant] laughed so hard as she recalled Menzel's speeches that she fell from her chair and landed flat on her back on the restaurant floor. Menzel's explanations for the [UFO] cases were so ridiculous that only propriety and respect for a senior colleague prevented the members of the team, including Condon, from laughing openly in his face. (Westrum, 35)</blockquote>

Though most of Menzel's harshest critcs were UFO researchers, negative criticism came from other fields: in 1959, prominent psychologist Carl Jung declared that Menzel "has not succeeded, despite all his efforts, in offering a satisfying explanation of even one authentic UFO report." (Jung, 147) Damning criticism also came from an internal U.S. Air Force analysis, which stated: