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03.03.2024 12:28, Dmitry Fedorov
Using the Galileo probe, astronomers discovered signs of continents and oceans on Earth, as well as the presence of oxygen in its atmosphere. This “discovery” plays a key role in the development of methods for analyzing and interpreting data on exoplanets and opens new opportunities for searching and studying potentially habitable worlds.
Image source: Ryder H. Strauss/arXiv, The Astronomical Journal
In a report published on arXiv.org, a team of astronomers led by Ryder H. Strauss of Northern Arizona University (NAU), presented the results of an analysis of data collected by the Galileo spacecraft during its gravity maneuvers near Earth in 1990 and 1992. The astronomers used spectrophotometric observations made by the Limited Solid State Imager (SSI), using a set of narrow-band filters (violet, green, red and four near-infrared) to study the reflected light from Earth.
The analysis showed that the variability in the light curves of the entire disk of the Earth can be explained by changing weather, the presence of continents, oceans and clouds on the rotating planet. In addition, temporal dynamics of disk color are attributed to oceans (blue shift) and land with vegetation (red shift).
Measuring the light intensity of the Earth through red and violet filters, as well as in the infrared range IR-6560 and violet during the Galileo probe flyby of the Earth in 1990
The decrease in reflectivity observed in some infrared filters is associated with weak absorption of radiation by water vapor and strong absorption by molecular oxygen. These results highlight the importance of molecular oxygen in the Earth’s atmosphere as a key indicator of its habitability.
The data obtained will be used to further validate and improve the three-dimensional spectral model of the Earth being developed by NASA’s Virtual Planetary Laboratory (VPL). This approach will significantly improve methods for observing exoplanets, including potentially habitable ones, and expand our understanding of the possibility of the existence of life beyond its home planet.
The study confirms that observations of the full disks of solar system planets can serve as an important analog for the analysis of exoplanets. Of particular importance in this context is Earth as the only known habitable world, making it a key target for study in the search for potentially habitable exoplanets.
