Using Deep Space Climate Observatory Measurements to Study the Earth as An Exoplanet

TL;DR

This paper demonstrates how data from the DSCOVR satellite can be used to infer Earth's properties as an exoplanet, providing a novel approach for exoplanet characterization using single-point light measurements.

Contribution

It introduces a method to derive planetary rotation, cloud patterns, surface type, and orbit from single-point multi-wavelength light curves, simulating exoplanet observations.

Findings

Successfully inferred Earth's rotation period from data

Simulated phase angle variations to mimic exoplanet observations

Determined minimum data collection rate for rotation period detection

Abstract

Even though it was not designed as an exoplanetary research mission, the Deep Space Climate Observatory (DSCOVR) has been opportunistically used for a novel experiment, in which Earth serves as a proxy exoplanet. More than two years of DSCOVR Earth images were employed to produce time series of multi-wavelength, single-point light sources, in order to extract information on planetary rotation, cloud patterns, surface type, and orbit around the Sun. In what follows, we assume that these properties of the Earth are unknown, and instead attempt to derive them from first principles. These conclusions are then compared with known data about our planet. We also used the DSCOVR data to simulate phase angle changes, as well as the minimum data collection rate needed to determine the rotation period of an exoplanet. This innovative method of using the time evolution of a multi-wavelength, reflected single-point light source, can be deployed for retrieving a range of intrinsic properties of an exoplanet around a distant star.