Scientists identify possible source of ‘unusual radar signatures’ at the edge of the Solar System


Scientists believe they have found an explanation for “unusual radar signatures” found at the edge of the solar system.

Icy satellites that are in orbit around Jupiter and Saturn have perplexed scientists because they are so different from both rocky worlds and most ice on Earth. The markedly different radar signatures have led to questions about how they are composed.

The objects are also extremely bright, even in areas that would be expected to be dark.

“Six different models have been published in an attempt to explain the radar signatures of the icy moons that orbit Jupiter and Saturn,” said Jason Hofgartner, a co-author of the new study. “The way these objects scatter radar is drastically different than that of the rocky worlds, such as Mars and Earth, as well as smaller bodies such as asteroids and comets.”

Now scientists believe that a specific effect, known as the coherent backscatter opposition effect or CBOE, is likely to explain the extraordinary radar signatures coming back from the satellites.

“When you’re at opposition, the Sun is positioned directly behind you on the line between you and an object, the surface appears much brighter than it would otherwise,” Hofgartner said. “This is known as the opposition effect. In the case of radar, a transmitter stands in for the Sun and a receiver for your eyes.”

The work is described in an article, ‘An icy-satellite radar-properties continuum that requires the coherent backscatter effect’, published in Nature Astronomy today.