Harold Irving Ewen
| Harold Irving Ewen | |
|---|---|
| Born | March 5, 1922 | 
| Died | October 8, 2015 (aged 93) | 
| Education | Ph.D. (1951) | 
| Alma mater | Harvard University | 
| Known for | Detection of 21-cm hydrogen line | 
| Spouse | Mary Ann Whitney | 
| Children | Donald, Bruce, Mark, Deborah, David, Daniel, and Rebecca | 
| Parents | 
 | 
| Awards | IEEE Morris E. Leeds Award (1970) Beatrice M. Tinsley Prize (1988) | 
| Scientific career | |
| Thesis | Radiation from Galactic Hydrogen at 1420 Megacycles per Second (1951) | 
| Doctoral advisor | Edward M. Purcell | 
Harold Irving "Doc" Ewen (March 5, 1922 – October 8, 2015) was an American physicist, radio astronomer, and business executive. He served in the United States Navy in World War II as a second lieutenant. As a graduate student under Edward M. Purcell, he was the first to detect the galactic 21-cm hydrogen line.