Luigi Giuseppe Jacchia | |
|---|---|
 Luigi Jacchia in 1928, aged 18 | |
| Born | (1910-06-04)June 4, 1910 Trieste, Austro-Hungarian Empire |
| Died | May 8, 1996(1996-05-08) (aged 85) Cambridge, Massachusetts, U.S. |
| Occupations | |
| Known for | Jacchia Reference Atmosphere |
| Awards | Hodgkins Medal (1980) |
| Academic background | |
| Education | University of Bologna (PhD) |
| Thesis | Study of the Debye effect in castor oil (1932) |
| Academic work | |
| Institutions | Harvard College Observatory Massachusetts Institute of Technology Smithsonian Astrophysical Observatory |
| Main interests | Atmospheric physics |
Luigi Giuseppe Jacchia (June 4, 1910 – May 8, 1996) was an Italian andnaturalized-Americanphysicist andastronomer at theHarvard College Observatory and theSmithsonian Astrophysical Observatory. He won theHodgkins Medal for his discovery thatsolar weather causes expansion of thethermosphere and increasesdrag on satellites inlow-Earth orbit.[1]
Jacchia was born in 1910 inTrieste, thenAustro-Hungary, to an affluent family of merchants.[2] His father wasItalian-Jewish, and his mother was an ItalianCatholic who later converted. In Trieste, he attended primary school in German and later studied inWeimar Germany before returning to Italy to complete secondary school inUdine. At thelyceum, he initially studiedengineering until discovering an interest in astronomy. He was mentored byGuido Horn d'Arturo, who invited him to join theObservatory of Bologna.[2]
He attended theUniversity of Bologna, earning a doctorate in physics in 1932.[3] His thesis characterized theDebye effect in oil.[4]
As a student inBologna between 1929 and 1931, Jacchia worked in astronomy andmeteorology research at the Observatory of Bologna. After graduating, he became an assistant at the observatory, part of theNational Institute for Astrophysics, where he studiedvariable stars.[5] He taught at the University of Bologna for seven years.
After the declaration ofracial laws by thefascist government of Italy in 1938, Jacchia lost his position at the observatory. He fled Italy in 1939 and joined the Harvard College Observatory as a research associate inCambridge, Massachusetts.[6] Once in the United States, he supported theAllied forces duringWorld War II by working as a scientific consultant and linguist for the Language Broadcasting and Monitoring Service at theU.S. Office of War Information.[7]
He returned toHarvard after the war to conduct research on atmospheric dynamics and later became a research associate atMIT.[8] Jacchia collaborated with physicists such asFred Lawrence Whipple,Zdeněk Kopal,[9] Franco Verniani,[10]Leon Campbell, and Jack William Slowey.[11]
In 1956, Whipple invited Jacchia to join the Smithsonian Astrophysical Observatory (SAO).[8] There, he analyzed orbit telemetry data fromNASA'sExplorer 8 satellite collected by SAO's global network ofBaker-Nunn cameras to analyze atmospheric perturbations on its orbitaltrajectory. In 1964, he used this data to characterizediurnaldensity fluctuations in the thermosphere caused by the Sun.[12] Along with Verniani, he also discovered the effect ofsunspots andsolar flares on atmospheric heating and the resulting increase ofatmospheric drag for spacecraft in low-Earth orbit. His work helped explain the rapid re-entry ofSkylab in 1979 after a period of high solar activity.[13] The SAO described this finding as "one of the major milestones in space physics...often compared to the discovery of theVan Allen radiation belts"[7] and awarded him the Hodgkins Medal in 1980.[14]
Jacchia wrote over 200 scientific papers on topics ranging fromatmospheric physics,comets, andmeteors. He was a member of theInternational Astronomical Union (IAU),American Astronomical Society (AAS),International Association of Geodesy (IAG), and theCommittee on Space Research (COSPAR). He was also involved in the planning of theInternational Geophysical Year (1957-1958).[8]
He died in 1996 after a long illness.[7]
Jacchianever married. He was apolyglot, speaking over twelve languages.[15] He witnessed the1972 Great Daylight Fireball.[7]
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