NASA is releasing the first images and sounds of an electrical connection between Saturn and one of its moons. The data collected by the agency's Cassini spacecraft enable scientists to improve their understanding of the complex web of interaction between the planet and its numerous moons. The results of the data analysis are published in the journals Nature and Geophysical Research Letters. Scientists previously theorized an electrical circuit should exist at Saturn. After analyzing data that Cassini collected in 2008, scientists saw a glowing patch of ultraviolet light emissions near Saturn's north pole that marked the presence of a circuit, even though the moon is 150,000 miles (240,000 kilometers) away from the planet.
The patch occurs at the end of a magnetic field line connecting Saturn and its moon Enceladus. The area, known as an auroral footprint, is the spot where energetic electrons dive into the planet's atmosphere, following magnetic field lines that arc between the planet's north and south polar regions. "The footprint discovery at Saturn is one of the most important fields and particle revelations from Cassini and ultimately may help us understand Saturn's strange magnetic field," said Marcia Burton, a Cassini fields and particles scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "It gives us the first visual connection between Saturn and one of its moons."
The auroral footprint measures approximately 750 miles by less than 250 miles, covering an area comparable to California or Sweden. At its brightest, the footprint shone with an ultraviolet light intensity far less than Saturn's polar auroral rings, but comparable to the faintest aurora visible at Earth without a telescope in the visible light spectrum. Scientists have not found a matching footprint at the southern end of the magnetic field line. "Cassini fields and particles instruments found particle beams aligned with Saturn's magnetic field near Enceladus, and scientists started asking if we could see an expected ultraviolet spot at the end of the magnetic field line on Saturn," said Wayne Pryor, a lead author of the Nature study released today, and Cassini co-investigator at Central Arizona College in Coolidge, Ariz. "We were delighted to find the glow close to the 'bulls-eye' at the center of our target."
The patch occurs at the end of a magnetic field line connecting Saturn and its moon Enceladus. The area, known as an auroral footprint, is the spot where energetic electrons dive into the planet's atmosphere, following magnetic field lines that arc between the planet's north and south polar regions. "The footprint discovery at Saturn is one of the most important fields and particle revelations from Cassini and ultimately may help us understand Saturn's strange magnetic field," said Marcia Burton, a Cassini fields and particles scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "It gives us the first visual connection between Saturn and one of its moons."
The auroral footprint measures approximately 750 miles by less than 250 miles, covering an area comparable to California or Sweden. At its brightest, the footprint shone with an ultraviolet light intensity far less than Saturn's polar auroral rings, but comparable to the faintest aurora visible at Earth without a telescope in the visible light spectrum. Scientists have not found a matching footprint at the southern end of the magnetic field line. "Cassini fields and particles instruments found particle beams aligned with Saturn's magnetic field near Enceladus, and scientists started asking if we could see an expected ultraviolet spot at the end of the magnetic field line on Saturn," said Wayne Pryor, a lead author of the Nature study released today, and Cassini co-investigator at Central Arizona College in Coolidge, Ariz. "We were delighted to find the glow close to the 'bulls-eye' at the center of our target."
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