from NASA The Juno spacecraft is “listening” to radio broadcasts from Jupiter’s volcanic moon Io, allowing researchers to find out what triggers the strange radio waves.
Of all the planets in our solar system, Jupiter has the largest and strongest magnetic field, which extends so far that some of the planet’s moons orbit within it. Because Io is closest to the planet, the moon is “caught in a gravitational tug of war” between Jupiter and two other large moons, according to NASA. These opposing pulls cause massive internal heat, which has led to hundreds of volcanic eruptions on the moon’s surface.
Volcanoes release 1 ton of gas and particles per second into space, NASA said in a statement. Some of this material splits into electrically charged ions and electrons which then rain down on Jupiter through the planet’s magnetic field. Electrons captured in the magnetic field are accelerated toward Jupiter’s poles and, along the way, generate a phenomenon scientists call HF radio waves (also known as HF radio emissions, or DAM).
Related: Amazing Photos: Io, Jupiter’s Volcanic Moon
When the spacecraft is in the right place to listen, Juno’s Waves instrument can pick up those radio waves, Yasmina Martos of NASA’s Goddard Space Flight Center said in the statement. Researchers used Juno data to determine where radio emissions are coming from in Jupiter’s massive magnetic field. The data sheds light on the behavior of the huge magnetic fields created by the gas giants.
According to the research team, radio waves come from space which can be described as a hollow cone, where the conditions are ideal: the right magnetic field strength and the right electron density. The signal spins like a beacon, and Juno only picks it up when the “light” shines on the spacecraft, according to the NASA statement.
The radio data also showed that the electrons that create these radio waves emit a massive amount of energy, 23 times more than the researchers expected. These electrons can also come from other sources, such as the planet’s magnetic field or a solar wind, according to the research team.
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