A study co-authored by Dr. Jason Hofgartner of the Southwest Research Institute investigates the unusual radar signatures of icy satellites around Jupiter and Saturn. These radar signatures sharply differ from those of rocky planets and most terrestrial ice, presenting a long-standing challenge for scientists. The research identifies the coherent backscatter opposition effect (CBOE) as a likely explanation for these strange radar properties. This effect causes icy surfaces to appear significantly brighter under certain observational conditions, with the radar transmitter mimicking the Sun’s position during observations. Hofgartner notes that unlike rocky worlds, icy moons exhibit a unique brightness pattern where the center appears much brighter than the edges. The study also suggests that the surfaces of these moons are highly irregular, dominated by icy rocks that scatter radar signals in various directions, leading to their distinct polarization signatures. The findings are based on radar observations from the decommissioned Arecibo Observatory. Hofgartner and his team aim to conduct further observations and analyze additional archival data to enhance understanding of icy satellites and their radar characteristics. The research was published in Nature Astronomy.
