July 8, 2014
NASA Scientists Confirm Voyager 1 Is Traveling Through Interstellar Space
redOrbit Staff & Wire Reports - Your Universe Online
A new “tsunami wave” generated by the sun has helped NASA scientists confirm that Voyager 1 is currently traveling through interstellar space, or the area between the stars that is filled with charged particles known as plasma, the US space agency reported on Monday.Waves like these are what initially led astronomers to conclude that the spacecraft had escaped the magnetic bubble surrounding the sun and planets known as the heliosphere in the fall of 2013. Voyager’s Plasma Wave Science Instrument detected electron waves in the plasma (or ionized gas) as the probe traveled through this region.
These waves are also known as “interstellar music,” and while they cannot be detected by the human ear, they occur at audio frequencies between a few hundred and a few thousand hertz, researchers explained at the time. For that reason, they were able to listen to the data through a loudspeaker while also successfully determining the density of the gas surrounding the spacecraft through the pitch and frequency.
[ Watch the Video: Voyager Captures Sounds Of Interstellar Space ]
According to Ed Stone of the California Institute of Technology, who has served as the Voyager mission project scientist for more than four decades, interstellar space is typically “like a quiet lake, but when our sun has a burst, it sends a shock wave outward that reaches Voyager about a year later. The wave causes the plasma surrounding the spacecraft to sing.”
The data collected from this most recent tsunami wave confirmed that Voyager is traveling through interstellar space, as expected. While the spacecraft has not yet departed our solar system, as it has not yet reached a final halo of comets surrounding the sun, it has made it past the heliosphere. This makes Voyager 1 the first human-made Earth probe to reach this vast region of space, and the furthest-traveled spacecraft of its kind.
“All is not quiet around Voyager,” explained University of Iowa scientist Don Gurnett, the principal investigator of the plasma wave instrument which collected the evidence that Voyager had left the sun’s heliosphere. “We're excited to analyze these new data. So far, we can say that it confirms we are in interstellar space.”
During periods of increased solar activity, our sun undergoes events known as coronal mass ejections during which it forcibly ejects material from its surface and flings it into space. These coronal mass ejections generate shock waves, three of which have reached Voyager 1 since the spacecraft first entered interstellar space in 2012, NASA said.
While the first was too small to be noticed at first, and was only discovered later, the second was clearly detected by Voyager’s cosmic ray instrument in March of last year, the agency noted. Now a new set of readings have been discovered, belonging to a third wave that was first registered this March.
“These data show that the density of the plasma is similar to what was measured previously, confirming the spacecraft is in interstellar space,” said NASA. “Thanks to our sun's rumblings, Voyager has the opportunity to listen to the singing of interstellar space – an otherwise silent place.”