Taking advantage of a total lunar eclipse, astronomers using NASA’s Hubble Space Telescope have detected Earth’s own brand of sunscreen—ozone—in our atmosphere. This method simulates how astronomers and astrobiology researchers will search for evidence of life beyond Earth by observing potential “biosignatures” on exoplanets (planets around other stars).
Source:
https://phys.org/news/2020-08-hubble-earth-proxy-oxygen-potentially.html