Quirks & Quarks

Voyager 1 picks up the 'hum' of interstellar space

The hum is a vibration in the interstellar plasma that can give scientists an idea of the density of space our solar system is travelling through

These measurements will help scientists map out the plasma environment that we're travelling through

In an artist's depiction, the Voyager 1 craft continues to cruise through interstellar space. (NASA / JPL)

The Voyager 1 spacecraft that launched in 1977 has travelled so far that not only has it moved beyond our sun's reach, but finally scientists have picked up their first clear signature of interstellar space itself.

Stella Ocker, a doctoral student in the astronomy department at Cornell University, described the signal as like a quiet "hum" in the interstellar plasma — ionized gas — that's inaudible to the human ear. 

In 2012 the spacecraft first crossed the boundary of our solar system's heliosphere, which is a giant bubble formed by the solar wind from the sun that envelops the sun and the planets. 

The solar wind, which is made up of charged particle emitted by the sun, is also a plasma, and fills up our heliosphere and pushes against the plasma from interstellar space like two winds blowing against each other. 

Until recently, Voyager 1 kept picking up bursts of plasma coming from our sun that are called coronal mass ejections. These send shock waves through the heliosphere that protrude out into interstellar space, so it's taken a while to get beyond the reach of these bursts.

Ocker told Quirks & Quarks host Bob McDonald how this signal from the interstellar medium can give us a better understanding of our own solar system, by knowing what it's like on the other side, and further, that it can tell us about the part of the galaxy we're travelling through.

You can listen to the interview with Stella Ocker by clicking the link above.

Produced and written by Sonya Buyting

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