Voyager probe's third solar 'tsunami' wave the longest ever encountered

This artist's concept shows NASA's Voyager 1 spacecraft flying through interstellar space. Image credit: NASA/JPL-Caltech

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Scott Sutherland

Meteorologist/Science Writer

Tuesday, December 16, 2014, 6:57 PM - The wave of solar matter that passed by Voyager 1 earlier this year has now lasted for around 10 months, and may still be going on now. This is the longest-lasting 'solar tsunami' the interstellar traveller has encountered so far.

When scientists confirmed that NASA's Voyager 1 spacecraft had passed into interstellar space, beyond the influence of our Sun's heliosphere, they were able to determine this due to waves of matter from the Sun that swept past it.

These waves started out as eruptions from the surface of the Sun - coronal mass ejections or CMEs - that were blasted out during solar flares. When they passed Voyager 1 far out in space, after over a year of travel, they caused the gas molecules in the interstellar medium to resonate. With this vibration detected by Voyager, NASA scientists were able to play this back as a form of eerie music.

CLICK BELOW TO LISTEN: Voyager treats us to the 'sounds of interstellar space'.

RELATED: Solar 'tsunami wave' helps confirm that Voyager 1 is in interstellar space

Whereas the first two CMEs that reached Voyager - in October to November of 2012 and in April to May of 2013 - allowed the researchers to get the first indication and then confirmation that the spacecraft had reached this incredible milestone, Voyager encountered a third starting in February of 2014. At the time the researchers cut off their recording, so that they could research and then publish their findings, this third wave was still going on, 10 months later. According to the latest JPL news release, it could even still be going on today.

Furthermore, a new remarkable result seen from the study of these three encounters is that the density of the interstellar medium is actually going up as Voyager gets further away from the Sun's heliosphere.

"Is that because the interstellar medium is denser as Voyager moves away from the heliosphere," says Ed Stone, the project scientist for the Voyager mission at Caltech, according to the press release. "or is it from the shock wave itself? We don't know yet."

CLICK TO WATCH BELOW: See, and hear, the three solar tsunamis that Voyager 1 has encountered.

"Most people would have thought the interstellar medium would have been smooth and quiet. But these shock waves seem to be more common than we thought," said Don Gurnett, the University of Iowa physics professor presenting these findings at the 2014 American Geophysical Union meeting in San Francisco, according to NASA.

As for exactly how long this wave of plasma will last, that's not known at this time. With most of Voyager's cameras and instruments shut down, so it's only able to pick up these resonances, there's no way to see the wave, how fast it's moving or even how much space it stretches across.