Martin Schmidt in 1978. Credit: Caltech
Dutch-American astronomer Martin Schmidt, who lived and worked in the United States for most of his life, died last Saturday at the age of 92. In 1963, he was the first to discover that quasi-stellar objects (QSOs), known as quasars, are cosmologically distant, that is, they are very far from Earth and that they existed in the early universe. Schmidt was born in Groningen and received his Ph.D. in 1956 with Jan Hendrik Oort in Leiden with a thesis on galactic mass distribution. In 1959, he joined the California Institute of Technology. Initially he was interested in the mass distribution and dynamics of galaxies, and published a famous paper in 1965 on the galactic rotation curve.
Then he went to study the spectra of light from radio sources. In 1963, he was the first to measure the quasar’s distance using hydrogen emission lines in the spectrum to determine the redshift of the 3C 273 quasar, previously detected using the Cambridge interferometer and Parks radio telescope. Quasars are star-like objects – distant galaxies – that have a spectrum in which spectral lines turn strongly red. We now know that galaxies at their center have a very active supermassive black hole that outshines the entire surrounding galaxy. Later, he was involved in X-ray and gamma research of the universe. In 2008 he won the Kavli Prize for Astrophysics with Donald Linden Bell. Source: Wikipedia.
