September 12, 2013
Voyager 1 Has Left Solar System, Reaching New Horizons
[ Watch the Video: Are We There Yet? NASA Says Yes ]
Lee Rannals for redOrbit.com - Your Universe OnlineMan has officially embarked on a new adventure that surpasses Lewis and Clark's excursion across the US, as NASA's Voyager 1 spacecraft officially reaches interstellar space.
The US space agency announced on Thursday that after traveling through space for 36 years, the probe has finally ventured out into interstellar space, becoming the first man-made object to travel beyond our Solar System.
Voyager 1 has traveled about 12 billion miles away from the sun, and new and unexpected data from the veteran spacecraft published in the journal Science shows the probe has finally accomplished this significant feat.
[ Watch the Video: Voyager Reaches Interstellar Space ]
"Now that we have new, key data, we believe this is mankind's historic leap into interstellar space," said Ed Stone, Voyager project scientist based at the California Institute of Technology, Pasadena. "The Voyager team needed time to analyze those observations and make sense of them. But we can now answer the question we've all been asking -- 'Are we there yet?' Yes, we are."
Voyager 1 has been traveling for about a year in a transitional zone between our Solar System and interstellar space. Scientists have been looking for three signs in order to determine whether or not this spacecraft has officially left its galactic neighborhood, including witnessing charged particles disappear, cosmic rays from the outside zooming in, and an abrupt change in the direction of the magnetic field. For a while scientists had only seen the charged particles and cosmic ray signs, and were waiting for the change in the magnetic field. However, that wait had been over for a longer time than the scientists knew.
NASA says that Voyager 1 actually left our Solar System back in August 2012, when an abrupt change in the density of energetic particles were first detected.
"We literally jumped out of our seats when we saw these oscillations in our data -- they showed us the spacecraft was in an entirely new region, comparable to what was expected in interstellar space, and totally different than in the solar bubble," Don Gurnett, who led the analysis, said. "Clearly we had passed through the heliopause, which is the long-hypothesized boundary between the solar plasma and the interstellar plasma."
Voyager 1 first detected an increased pressure of interstellar space on the heliosphere in 2004. The heliosphere is the bubble of charged particles surrounding the sun that reaches beyond the outer planets. After this discovery, scientists began searching for evidence of the spacecraft's interstellar arrival, sifting through loads of data for years.
Scientists used a coronal mass ejection (CME) that erupted from the sun in March 2012 to help measure the spacecraft's plasma environment to make a determination of its location. This CME didn't arrive to the probe until April 2013, when the plasma around the spacecraft began to vibrate like a violin string. The pitch of the oscillations helped scientists determine the density of the plasma, showing the spacecraft was bathed in plasma more than 40 times denser than they had encountered in the outer layer of the heliosphere. NASA says that this sort of density is what you would expect in interstellar space.
"The team's hard work to build durable spacecraft and carefully manage the Voyager spacecraft's limited resources paid off in another first for NASA and humanity," said Suzanne Dodd, Voyager project manager, based at NASA's Jet Propulsion Laboratory, in Pasadena, Calif. "We expect the fields and particles science instruments on Voyager will continue to send back data through at least 2020. We can't wait to see what the Voyager instruments show us next about deep space."
NASA said it will continue to be gathering information from Voyager 1 as it courageously trots its way through the depths of the unknown.
"Voyager has boldly gone where no probe has gone before, marking one of the most significant technological achievements in the annals of the history of science, and adding a new chapter in human scientific dreams and endeavors," said John Grunsfeld, NASA's associate administrator for science in Washington. "Perhaps some future deep space explorers will catch up with Voyager, our first interstellar envoy, and reflect on how this intrepid spacecraft helped enable their journey."