Light from the most distant quasar yet seen reveals details about the chemistry of the early universe.
CREDIT: ESO/M. Kornmesser  Enlarge

Astronomy changed forever 50 years ago this week, when scientists first began to understand the true nature of quasars, the brightest objects in the universe.

On March 16, 1963, Dutch-born astronomer Maarten Schmidt published the first-ever definitive measurement of the distance to aquasar, finding that a puzzling object called 3C 273 lies about 2.5 billion light-years from Earth.

The stunning discovery showed that 3C 273's inherent luminosity must be off the charts for it to appear so bright despite its immense distance. The object was no star, despite the starlike characteristics of its light emissions. ("Quasar" is short for "quasi-stellar radio source.")

Over time, astronomers figured out that quasars actually shine from the cores of galaxies, blazing forth when the supermassive black holes that lurk there gobble up huge quantities of gas, dust and other matter. Still, there remain many mysteries about quasars that researchers have yet to solve. caught up with Schmidt, now a professor emeritus at Caltech in Pasadena, this week to discuss quasars, how they have improved our understanding of the universe and how he feels on the cusp of this big anniversary: So how does it feel now, 50 years after making that seminal discovery?

Maarten Schmidt: Besides the fact that I'm 50 years older (laughs)? It's somewhat hard to believe.

Quasars have had a major effect on astronomy, because they introduced black holes in astronomy. And of course they are objects that are so immensely bright you can see them all over the universe. [The History & Structure of the Universe (Infographic)] Are the memories of the discovery still vivid in your mind?

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