The Sound of Silence: NASA Probes Record Earth’s ‘Chorus’

Here’s a question for Science teachers to ask their classes:

If space made a noise, what would it sound like? The reverberations of Neil Armstrong’s footsteps? Space junk clanging together?  The chatter of little green men?

Or perhaps, early morning birdsong?

An illustration of the earth’s magnetosphere, where our planet’s magnetic field collides with charged particles from the Sun.

Yes, unlikely as it is, Earth actually gives off a noise that most liken to birds’ chirping. We know this because when NASA wasn’t busy sending a rover to explore Mars, it created a device to detect the sounds of an atmosphere much closer to home.

Surrounding our planet are rings of plasma… which are pulsing with radio waves. Those waves are not audible to the human ear alone, but radio antennae can pick them up, and that’s just what an instrument — the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) — on NASA’s recently launched Radiation Belt Storm Probes has done.

Scientists have known of Earth’s “chorus” for several decades, but one of the missions of the Probes project has been to uncover the science behind the emissions. The sounds come from a part of Earth’s outer atmosphere called the magnetosphere (pictured above) “an area where charged particles from the sun interact with the earth’s magnetic field.”

Fortunately for us, the radio waves emitted by Earth’s atmosphere occur in the same frequency of sounds we can hear. That means that, once the waves are picked up by a radio transmitter and translated into sound waves, we can listen to the hauntingly beautiful sounds of our home planet, recorded below:

The project will continue for two more years and will also investigate the phenomenon of “space weather,” which actually affects us on the ground by knocking out satellites and power grids. Who knew space suffered weather like the rest of us?

Idea for a Classroom Activity: Earth’s Song

Objective: To help students connect the concepts of magnetic fields and radio waves.

Grade Level: 4-8

Time Needed: 20-30 minutes

Dialogue/Worksheet: Can you imagine what space would sound like if we could listen to it? What kind of sounds do you think we would hear?

(Have students draw Earth and its magnetic field. This activity should follow a unit on magnetism and polarity.)

Did you know that the magnetic field makes a noise when tiny particles from the Sun hit it? We can’t hear this sound just by listening with our ears. We need radio waves to be able to hear it. What kinds of objects detect radio waves?

(Have students list the many different items that pick up radio waves. Ex. radios, baby monitors, garage door openers, cell phones, radio-controlled toys, TVs, wifi, airplanes etc.)

Radio waves make up a a type of sound wave that travels through the air at a frequency humans can’t hear. They travel much faster than the sound waves you hear when I speak. But we can hear them when we use a radio. The antennae pick up radio waves from the air and switch them into sound waves, which we can hear through the speakers. 

Earth’s magnetic field gives off its own noise because radio waves are  electromagnetic. Using a radio antennae, we can pick up this sound and listen to the planet. 

(Play audio of Earth’s chorus.)

What did that sound like to you? Did its sound surprise you? If you could give Earth’s song a name, what would you call it?

Resources:

NASA explains Radio Waves

eNotes Reference Guide: Electricity and Magnetism

eNotes Q&A: Definition of radio waves


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