Voyager 1 left the solar system on August 25, 2012 after more than 35 years of traveling. That’s the startling report published today in Geophysical Research Letters .
Dr. Bill Webber, an astronomer from New Mexico and one of the authors of the study, said that the radiation levels received by the Voyager changed dramatically on that date, signalling that the unmanned explorer had finally left the heliosphere — the region of space affected by the solar wind from our sun. “Within just a few days, the heliospheric intensity of trapped radiation decreased, and the cosmic ray intensity went up as you would expect if it exited the heliosphere,” he said.
But has Voyager 1 really become the first earthly object to leave our solar system? Caltech’s Edward Stone was quoted in USA Today as saying that NASA was aware of today’s announcement but didn’t agree with it.
It’s their official position that the Voyager 1 actually entered a region of space that they call the “magnetic highway.” The level of radiation changed when the vehicle entered that region, but “this region is still inside our solar bubble because the direction of the magnetic field lines has not changed.”
Stone described the process of traveling through the magnetic highway as the last leg on the journey, but he said that it could be months or even up to two years before Voyager 1 finally crosses the boundary into a zone that everyone can agree is outside the solar system.
This photograph, courtesy JPL and NASA, is a montage of Saturn and its many moons put together by the Voyager 1 unmanned spacecraft when it approached the ringed planet’s territory in November 1980:
Maybe Voyager 1 has left the building, and maybe it hasn’t. Either way, it remains on track to be the first human-made object to ever leave our solar system.
Built with laughably primitive computers and 1970s technology, Voyager 1 is the longest-operating spacecraft of all time.
[X-ray Image: NASA/CXC/ASU/J. Hester et al. and Optical Image: NASA/HST/ASU/J. Hester et al. for combined colorful image of the Crab Nebula]
