CAPE CANAVERAL, Florida -- Data from NASA's Voyager 1 spacecraft indicate that the venerable
deep-space explorer has encountered a region in space where the
intensity of charged particles from beyond our solar system has markedly
increased. Voyager scientists looking at this rapid rise draw closer to
an inevitable but historic conclusion – that humanity's first emissary
to interstellar space is on the edge of our solar system.
"The laws of physics say that someday Voyager will become the first
human-made object to enter interstellar space, but we still do not know
exactly when that someday will be," said Ed Stone, Voyager project
scientist at the California Institute of Technology in Pasadena. "The
latest data indicate that we are clearly in a new region where things
are changing more quickly. It is very exciting. We are approaching the
solar system's frontier."
The data making the 16-hour-38 minute, 11.1-billion-mile
(17.8-billion-kilometer), journey from Voyager 1 to antennas of NASA's
Deep Space Network on Earth detail the number of charged particles
measured by the two High Energy telescopes aboard the 34-year-old
spacecraft. These energetic particles were generated when stars in our
cosmic neighborhood went supernova.
"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," said 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."
This marked increase is one of a triad of data sets which need to make
significant swings of the needle to indicate a new era in space
exploration. The second important measure from the spacecraft's two
telescopes is the intensity of energetic particles generated inside the
heliosphere, the bubble of charged particles the sun blows around
itself. While there has been a slow decline in the measurements of these
energetic particles, they have not dropped off precipitously, which
could be expected when Voyager breaks through the solar boundary.
The final data set that Voyager scientists believe will reveal a major
change is the measurement in the direction of the magnetic field lines
surrounding the spacecraft. While Voyager is still within the
heliosphere, these field lines run east-west. When it passes into
interstellar space, the team expects Voyager will find that the magnetic
field lines orient in a more north-south direction. Such analysis will
take weeks, and the Voyager team is currently crunching the numbers of
its latest data set.
"When the Voyagers launched in 1977, the space age was all of 20 years
old," said Stone. "Many of us on the team dreamed of reaching
interstellar space, but we really had no way of knowing how long a
journey it would be -- or if these two vehicles that we invested so much
time and energy in would operate long enough to reach it.”
Launched in 1977 aboard Titan IIIE/Centaur rockest from Cape Canaveral Air Force Station in Florida, NASA says that Voyager 1 and 2 are in good health. Voyager 2 is more
than 9.1 billion miles (14.7 billion kilometers) away from the sun. Both
are operating as part of the Voyager Interstellar Mission, an extended
mission to explore the solar system outside the neighborhood of the
outer planets and beyond. NASA's Voyagers are the two most distant
active representatives of humanity and its desire to explore.
The Voyager spacecraft were built by NASA's Jet Propulsion Laboratory in
Pasadena, Calif., which continues to operate both. JPL is a division of
the California Institute of Technology. The Voyager missions are a part
of the NASA Heliophysics System Observatory, sponsored by the
Heliophysics Division of the Science Mission Directorate in Washington.
Images Credit: Artist Concepts - NASA/JPL-Caltech
