Astronomers have finally discovered the origin of an eerie whistling sound in space, referred to as the whistler mode chorus. The phenomenon has been linked to the sudden bursts of electrons in the magnetosphere.
Whistler Mode Chorus
A research team from the University of Minnesota combined data collected by NASA's FIREBIRD II CubeSat and Van Allen Probes mission to find that a common plasma wave in space is possibly the reason behind the impulsive loss of high-energy electrons into the atmosphere of the Earth.
The waves, which can accelerate electrons efficiently, are created by the fluctuations in magnetic and electric fields. They have typical rising tones that sound similar to the noise made by chirping birds. The research team published their findings in Geophysical Review Letters.
“Observing the detailed chain of events between chorus waves and electrons requires a conjunction between two or more satellites,” lead study author Aaron Breneman said. “There are certain things you can’t learn by having only one satellite — you need simultaneous observations at different locations.”
The two spacecraft happened to be located in the perfect position, which enabled them both to capture the impulsive electron loss. The FIREBIRD II flies at a height of 310 miles above the planet and the two Van Allen Probes travel in a wide orbit at 13,000 miles high above Earth.
The differences in the height at which the spacecraft are located, further, allowed the researchers to observe the cause of the fluctuating electrons from varying perspectives. While studying the combined data, the researchers found out that chorus waves in the Van Allen belts began making noise immediately before FIREBIRD II detected the microbursts.
NASA has stated that the new results are a confirmation that chorus waves play a significant part in controlling energetic electrons’ loss. The information can help scientists know why radiation belts hurl away high-energy electrons so violently. The knowledge can further aid in improving the predictions for space weather.
Spooky Space Sounds
The sounds in outer space can be a bit creepy at times, in fact, NASA had released a spooky space sound playlist last month to commemorate the occasion of Halloween. It was a compilation of sounds captured at various times by satellites traveling through the universe.
Even though the lack of atmosphere and space vacuum means that there is no way to relay sound waves, some spacecraft are still able to capture radio emissions in the cosmos. The radio waves that are captured are sent back to Earth and converted into sound waves.
For now, the eerie whistling noise of Whistler Mode Chorus, which sounds quite similar to a horror or a sci-fi film soundtrack, can be heard here on the agency’s Soundcloud account.