Voyager
1 reaching Interstellar Future
This
artist's concept shows NASA's two Voyager spacecraft exploring a turbulent
region of space known as the heliosheath, the outer shell of the bubble of
charged particles around our sun. Image credit: NASA/JPL-Caltech
Artist
concept of NASA's Voyager spacecraft. Image credit: NASA/JPL-Caltech
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,
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.
More information
about Voyager is available at: http://www.nasa.gov/voyager
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