Oxygen on Potentially Habitable Exoplanets
NASA | GSFC | STScI | HubbleSite | 2020 Aug 06
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).Hubble Views Moon to Study Earth ~ Credit: NASA/GSFC/USRAClick to play embedded YouTube video.
Hubble did not look at Earth directly. Instead, the astronomers used the Moon as a mirror to reflect sunlight, which had passed through Earth's atmosphere, and then reflected back towards Hubble. Using a space telescope for eclipse observations reproduces the conditions under which future telescopes would measure atmospheres of transiting exoplanets. These atmospheres may contain chemicals of interest to astrobiology, the study of and search for life.
Though numerous ground-based observations of this kind have been done previously, this is the first time a total lunar eclipse was captured at ultraviolet wavelengths and from a space telescope. Hubble detected the strong spectral fingerprint of ozone, which absorbs some of the sunlight. Ozone is important to life because it is the source of the protective shield in Earth's atmosphere. ...
Hubble Makes the First Observation of a
Total Lunar Eclipse by a Space Telescope
ESA Hubble Science Release | 2020 Aug 06
The Hubble Space Telescope's Near-UV and Optical Transmission
Spectrum of Earth as an Exoplanet ~ Allison Youngblood et al
- Astronomical Journal 160(3):100 (Sep 2020) DOI: 10.3847/1538-3881/aba0b4
- arXiv.org > astro-ph > arXiv:2008.01837 > 04 Aug 2020