Based on the latest data received from Voyager 1, scientists say the venerable spacecraft is now on the very edge of our solar system. The data, which traveled some 17.8 billion kilometers (11 billion miles) on its 16-hour-38 minute journey to NASA’s Deep Space Network on Earth, reveals a marked increase in the intensity of charged particles from beyond our solar system, indicating that Voyager 1 is soon to become the first man-made object to leave our little slice of the universe.

It is still unknown when exactly the 34-year-old Voyager 1 spacecraft will cross over into interstellar space, but that moment is definitely fast approaching.

“The latest data indicate that we are clearly in a new region where things are changing more quickly," says Voyager project scientist at the California Institute of Technology in Pasadena, Ed Stone. "It is very exciting. We are approaching the solar system's frontier."

"From January 2009 to January 2012, there had been a gradual increase of about 25 percent in the amount of galactic cosmic rays Voyager was encountering," says Stone. "More recently, we have seen very rapid escalation in that part of the energy spectrum. Beginning on May 7, the cosmic ray hits have increased five percent in a week and nine percent in a month."

The intensity of charged particles from beyond our solar system is just one of three measures scientists are keeping a close eye on to indicate Voyager 1’s breaking through the solar boundary. The second is the intensity of energetic particles generated inside the heliosphere, which has been in slow decline but has not dropped off drastically as is expected when Voyager enters interstellar space.

The third and final measure Voyager scientists are monitoring is the direction of the magnetic field lines surrounding the spacecraft. They expect that these field lines, which run east-west while Voyager is still within the heliosphere, will switch to a north-south orientation when Voyager crosses the interstellar boundary. The team is currently crunching the numbers of this data set, a task that is expected to take weeks.

Source: NASA