NASA's Voyager sends back freaky sound of interstellar space

You've no doubt heard NASA has officially declared that its Voyager 1 spacecraft has left our solar system, becoming the first-ever human-made object to do so. But have you heard the trippy soundtrack Voyager sent back from interstellar space?

NASA scientists confirmed the craft's move beyond the sun's heliosphere and into interstellar space by listening to radio transmissions sent back every six months by Voyager. The plasma, or ionized gas, in the heliosphere has a different density than the plasma of interstellar space. As PBS explains it, "When solar flares send ripples through the plasma, causing the particles to vibrate, two antennae on Voyager pick up the frequency and transmit it back to Earth as an audible radio transmission." Thus, a change in the sound would signal a move into the different plasma environment.