Hubble Uses Earth as a Proxy for Identifying Oxygen on Potentially Habitable Planets Around Other Stars

This illustration shows the Hubble Space Telescope superimposed on an image of the Moon, seen during a lunar eclipse. Taking advantage of a total lunar eclipse in January 2019, astronomers using NASA’s Hubble Space Telescope have detected ozone in Earth’s atmosphere. This method serves as a proxy for how they will observe Earth-like planets transiting in front of other stars in search of life. Our planet’s perfect alignment with the Sun and Moon during a total lunar eclipse mimics the geometry of a transiting terrestrial planet with its star. In a new study, Hubble did not look at Earth directly. Instead, astronomers used the Moon as a mirror that reflects the sunlight transmitted through Earth’s atmosphere, which was then captured by Hubble. This is the first time a total lunar eclipse was captured at ultraviolet wavelengths and from a space telescope. (Credits: M. Kornmesser (ESA/Hubble), NASA, and ESA)

GREENBELT, Md. (NASA PR) — 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).

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