In the 1930s, Caltech astronomer Fritz Zwicky would brave the chill atop Palomar Mountain near San Diego to peer through a small survey telescope in search of eruptions in the night sky. In the 1940s, he and his collaborator, astronomer Walter Baade, continued the quest using a larger survey telescope, the 48-inch Samuel Oschin telescope at Palomar Observatory, still in operation today .
The pair would ultimately go on to discover many stars whose lives ended in fiery explosions, and even coined a term for them: supernovae. In fact, Zwicky held the record for the most supernova discoveries-more than 120-until 2009.
Fast forward to now, and Zwicky's namesake, the Zwicky Transient Facility (ZTF)-a National Science Foundation-funded sky survey that began operations in 2017 using the 48-inch telescope-has detected about a hundred thousand supernovae. These detections, in turn, have led to the spectroscopic classification and confirmation of more than 10,000 supernovae.
"There are trillions of stars in the universe, and about every second, one of them explodes. Reaching 10,000 classifications is amazing, but what we truly should celebrate is the incredible progress we have made in our ability to browse the universe for transients, or objects that change in the sky, and the science our rich data will enable," says Christoffer Fremling, a staff astronomer at Caltech. Fremling leads the Bright Transient Survey (BTS), ZTF project that discovers and classifies new supernovae.
Nearly 16,000 supernovae have been discovered and confirmed since 2012, when astronomical databases started to officially keep track of all the discoveries. Of these objects, more than 10,000 have been detected by ZTF, making it the largest supernova survey to date.
