Discovered in March by astronomers using the Zwicky Transient Facility’s wide-field survey camera at the Palomar Observatory in San Diego County, California, Comet C/2022 E3 (ZTF) was last visible in the night sky during the Stone Age — about 50,000 years ago.
![Graduate student’s photos of green comet featured in major media outlets](https://ciera.northwestern.edu/wp-content/uploads/2023/02/C2022-E3-ZTF-Jan25-grayscale-Imran-Sultan-1-1024x775.jpg)
Credit: Imran Sultan