Voyager has left the solar system
Humanity is officially an interstellar species.
The team of space scientists who devised and launched the Voyager 1 spacecraft announced that, after reviewing data beamed back from the probe, it exited the solar system on about Aug. 25 of last year. It is the first man-made object to do so.
“By setting sail on the cosmic seas between the stars, Voyager has joined the other historic journeys of exploration such as the first circumnavigation of the Earth and the first
footprint on the moon,” said Voyager project scientist Ed Stone.
Beyond all of the sun’s planets and asteroids lies the heliopause, a boundary where charged particles blown outward by the sun meet with the interstellar medium, the space between the stars.
Last August, an instrument aboard Voyager observed a significant drop in the number of charged particles, mostly protons, bombarding the spacecraft from the sun.
However, to confirm that Voyager actually had flown beyond the sun’s reach, scientists needed to observe other evidence of a transition, such as change in the direction of the magnetic field.
And now they say they have done so.
“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,” said Don Gurnett, leader of Voyager 1’s plasma wave experiment.
The findings were disclosed in a paper published in Thursday’s issue of the journal Science.
Scientists around the world marveled at the technical achievement.
Voyager was launched in 1977, nearly four decades ago, and had a nominal four-year mission to Saturn. It had 65,000 individual parts, and after traveling 12 billion miles, many of those parts are still working. Scientists are still communicating with the spacecraft, which is now truly a starship.
“For me, the idea that NASAengineers built a spacecraft that was so well designed that it has traveled to interstellar space is what is thrilling,” said Nick Suntzeff, a Texas A&MUniversity astronomer. “Man, those guys did an amazing job. There are few voyages of discovery that I have experienced vicariously in my lifetime, and this was one.
“It is a grand achievement.”