The Spectrum of Earthshine: A Pale Blue Dot Observed from the Ground

By N. Woolf, P. Smith, Wesley A. Traub, K. Observatory, Az Tucson, H. C. F. Astrophysics, M. Cambridge. 2002

203 citations recorded by the source corpus.

We report the visible reflection spectrum of the integrated Earth, illuminated as it would be seen as a spatially unresolved extrasolar planet. The spectrum was derived from observation of lunar earthshine in the range 4800-9200 Å at a spectral resolution of about 600. We observe absorption features of ozone, molecular oxygen, and water. We see enhanced reflectivity at short wavelengths from Rayleigh scattering and apparently negligible contributions from aerosol and ocean water scattering. We also see enhanced reflectivity at long wavelengths starting at about 7300 Å, corresponding to the well-known red reflectivity edge of vegetation because of its chlorophyll content; however, this signal is not conclusive because of the breakdown of our simple model at wavelengths beyond 7900 Å.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/3d179d3416a40cc93b6c29c5d752efbad85ccea9

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In Astronomy and Astrophysics

Citations in the corpus

Spectropolarimetric signatures of Earth-like extrasolar planets (2007, methodology): “…cases modeled by different research groups (see e.g. Hamdani et al. 2006; Montañés-Rodrı́guez et al. 2006; Tinetti et al. 2006b,a; Seager et al. 2005; Woolf et al. 2002; Arnold et al. 2002) in spectra of Earthshine, the sunlight that has first been reflected by the Earth and then by the moon,…”
How to Characterize Habitable Worlds and Signs of Life (2017, methodology): “Models of disk-integrated spectra match observations obtained when using the Earth’s average atmosphere profile (see, e.g., Woolf et al. 2002, Montañés-Rodrı́guez et al. 2006, Turnbull et al. 2006, Kaltenegger et al. 2007, Arnold 2008, Robinson et al. 2011, Pallé et al. 2016).”
Exoplanet Atmospheres: Physical Processes (2010, background): “Global, instantaneous spectra and photometry can be obtained from observations from Earth itself—by Earthshine measurements (Arnold et al. 2002; Woolf et al. 2002).”
Spectral Evolution of an Earth-like Planet (2006, methodology): “Our line-by-line radiative transfer code has also been used for numerous full planetary disk modeling studies, both for theoretical studies (Des Marais et al. 2000; Traub and Jucks 2002) and fitting observed Earthshine spectra (Woolf et al. 2002; Turnbull et al. 2006).”
TRANSITS OF EARTH-LIKE PLANETS (2009, methodology): “Our line-by-line radiative transfer code for the Earth has been validated by comparison to observed reflection and emission spectra (Woolf et al. 2002; Turnbull et al. 2006; Christensen & Pearl 1997, Kaltenegger et al. 2007). πR2(λ) = πRp2 + 2πRph(λ) (4) To extend the validation data set to rays…”
Spectrum of a Habitable World: Earthshine in the Near-Infrared (2006, background): “The present work is a continuation of our visible-wavelength earthshine observations (Woolf et al. 2002).”
Exoplanet Biosignatures: A Review of Remotely Detectable Signs of Life (2017, background): “Des Marais et al. (2002) discussed the VRE as a surface biosignature of land vegetation, as it has been shown to be detectable in observations of Earth from the Galileo spacecraft (Sagan et al., 1993), as well as in the Earthshine spectrum of light reflected from the Moon (Arnold et al., 2002; Woolf”
Imaging Spectroscopy for Extrasolar Planet Detection (2002, background): “The dominant bands are from oxygen and water and may also be seen in the observed spectrum of Woolf et al. (2002).”