Jacques van Oene
May 24th 05, 03:39 PM
Dolores Beasley
Headquarters, Washington May 24, 2005
(Phone: 202/358-1753)
Bill Steigerwald
Goddard Space Flight Center, Greenbelt, Md.
(Phone: 301/286-5017)
Jane Platt
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone: 818/354-0880)
RELEASE: 05-131
VOYAGER SPACECRAFT ENTERS SOLAR SYSTEM'S FINAL FRONTIER
NASA's Voyager 1 spacecraft has entered the solar system's final
frontier. It is entering a vast, turbulent expanse, where the sun's
influence ends and the solar wind crashes into the thin gas between stars.
"Voyager 1 has entered the final lap on its race to the edge of interstellar
space," said Dr. Edward Stone, Voyager project scientist at the California
Institute of Technology in Pasadena. Caltech manages NASA's Jet Propulsion
Laboratory in Pasadena, which built and operates Voyager 1 and its twin,
Voyager 2.
In November 2003, the Voyager team announced it was seeing events unlike any
in the mission's then 26-year history. The team believed the unusual events
indicated Voyager 1 was approaching a strange region of space, likely the
beginning of this new frontier called the termination shock region. There
was considerable controversy over whether Voyager 1 had indeed encountered
the termination shock or was just getting close.
The termination shock is where the solar wind, a thin stream of electrically
charged gas blowing continuously outward from the sun, is slowed by pressure
from gas between the stars. At the termination shock, the solar wind slows
abruptly from a speed that ranges from 700,000 to 1.5 million mph and
becomes denser and hotter. The consensus of the team is Voyager 1, at
approximately 8.7 billion miles from the sun, has at last entered the
heliosheath, the region beyond the termination shock.
Predicting the location of the termination shock was hard, because the
precise conditions in interstellar space are unknown. Also, changes in the
speed and pressure of the solar wind cause the termination shock to expand,
contract and ripple.
The most persuasive evidence that Voyager 1 crossed the termination shock is
its measurement of a sudden increase in the strength of the magnetic field
carried by the solar wind, combined with an inferred decrease in its speed.
This happens whenever the solar wind slows down.
In December 2004, the Voyager 1 dual magnetometers observed the magnetic
field strength suddenly increasing by a factor of approximately 2 1/2, as
expected when the solar wind slows down. The magnetic field has remained at
these high levels since December. NASA's Goddard Space Flight Center,
Greenbelt, Md., built the magnetometers.
Voyager 1 also observed an increase in the number of high-speed electrically
charged electrons and ions and a burst of plasma wave noise before the
shock. This would be expected if Voyager 1 passed the termination shock. The
shock naturally accelerates electrically charged particles that bounce back
and forth between the fast and slow winds on opposite sides of the shock,
and these particles can generate plasma waves.
"Voyager's observations over the past few years show the termination shock
is far more complicated than anyone thought," said Dr. Eric Christian,
Discipline Scientist for the Sun-Solar System Connection research program at
NASA Headquarters, Washington.
The result is being presented today at a press conference in the Morial
Convention Center, New Orleans, during the 2005 Joint Assembly meeting of
Earth and space science organizations.
For more information about Voyager visit:
http://www.nasa.gov/vision/universe/solarsystem/voyager_agu.html
For information about NASA and agency programs on the Internet, visit:
http://www.nasa.gov/home/index.html
-end-
--
--------------
Jacques :-)
www.spacepatches.info
Headquarters, Washington May 24, 2005
(Phone: 202/358-1753)
Bill Steigerwald
Goddard Space Flight Center, Greenbelt, Md.
(Phone: 301/286-5017)
Jane Platt
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone: 818/354-0880)
RELEASE: 05-131
VOYAGER SPACECRAFT ENTERS SOLAR SYSTEM'S FINAL FRONTIER
NASA's Voyager 1 spacecraft has entered the solar system's final
frontier. It is entering a vast, turbulent expanse, where the sun's
influence ends and the solar wind crashes into the thin gas between stars.
"Voyager 1 has entered the final lap on its race to the edge of interstellar
space," said Dr. Edward Stone, Voyager project scientist at the California
Institute of Technology in Pasadena. Caltech manages NASA's Jet Propulsion
Laboratory in Pasadena, which built and operates Voyager 1 and its twin,
Voyager 2.
In November 2003, the Voyager team announced it was seeing events unlike any
in the mission's then 26-year history. The team believed the unusual events
indicated Voyager 1 was approaching a strange region of space, likely the
beginning of this new frontier called the termination shock region. There
was considerable controversy over whether Voyager 1 had indeed encountered
the termination shock or was just getting close.
The termination shock is where the solar wind, a thin stream of electrically
charged gas blowing continuously outward from the sun, is slowed by pressure
from gas between the stars. At the termination shock, the solar wind slows
abruptly from a speed that ranges from 700,000 to 1.5 million mph and
becomes denser and hotter. The consensus of the team is Voyager 1, at
approximately 8.7 billion miles from the sun, has at last entered the
heliosheath, the region beyond the termination shock.
Predicting the location of the termination shock was hard, because the
precise conditions in interstellar space are unknown. Also, changes in the
speed and pressure of the solar wind cause the termination shock to expand,
contract and ripple.
The most persuasive evidence that Voyager 1 crossed the termination shock is
its measurement of a sudden increase in the strength of the magnetic field
carried by the solar wind, combined with an inferred decrease in its speed.
This happens whenever the solar wind slows down.
In December 2004, the Voyager 1 dual magnetometers observed the magnetic
field strength suddenly increasing by a factor of approximately 2 1/2, as
expected when the solar wind slows down. The magnetic field has remained at
these high levels since December. NASA's Goddard Space Flight Center,
Greenbelt, Md., built the magnetometers.
Voyager 1 also observed an increase in the number of high-speed electrically
charged electrons and ions and a burst of plasma wave noise before the
shock. This would be expected if Voyager 1 passed the termination shock. The
shock naturally accelerates electrically charged particles that bounce back
and forth between the fast and slow winds on opposite sides of the shock,
and these particles can generate plasma waves.
"Voyager's observations over the past few years show the termination shock
is far more complicated than anyone thought," said Dr. Eric Christian,
Discipline Scientist for the Sun-Solar System Connection research program at
NASA Headquarters, Washington.
The result is being presented today at a press conference in the Morial
Convention Center, New Orleans, during the 2005 Joint Assembly meeting of
Earth and space science organizations.
For more information about Voyager visit:
http://www.nasa.gov/vision/universe/solarsystem/voyager_agu.html
For information about NASA and agency programs on the Internet, visit:
http://www.nasa.gov/home/index.html
-end-
--
--------------
Jacques :-)
www.spacepatches.info