hum

Forty-four years after it rocketed off from Earth, the Voyager 1 spacecraft is detecting the background “hum” of interstellar space for the first time. Voyager 1, launched in 1977, left the bounds of the solar system — known as the heliosphere — in 2012. The heliosphere is the bubble of space influenced by solar wind, the stream of charged particles that emanates from the sun. Since popping out of this bubble, Voyager 1 has been periodically sending back measurements of the interstellar medium. Occasionally, the sun sends off a burst of energy known as a coronal mass ejection that disturbs … Read more