| | The Bruce Medalists: Jan H. Oort |
 | | During World War II Oort started Hendrik C. van de Hulst on the successful search for a radio spectral line. |
| | Following the war Oort led the Dutch group which built a 25-m radio telescope at Dwingeloo and used the 21-cm line to map hydrogen gas in the Galaxy. |
| | They found the large-scale spiral structure, the galactic center, and gas cloud motions. |
| www.phys-astro.sonoma.edu /brucemedalists/Oort (407 words) |
