Wednesday, December 07, 2011 2:35:58 AM
Voyager probe reaches edge of Solar System's 'bubble'
Her 39-year-and-counting mission ... to boldly go
'Soon we find out what interstellar space is really like'
By Lewis Page
Posted in Space, 6th December 2011 08:46 GMT
NASA's famous Voyager 1 space probe, sailing outwards into the interstellar void far beyond the orbit of Pluto, has entered a new and never-before-seen region of space thought to be the very edge of the "bubble" maintained around the solar system by the power of the Sun.
"We shouldn't have long to wait to find out what the space between stars is really like," enthuses Ed Stone, Voyager project boffin.
The probe has been encountering strange, previously unseen phenomena in recent times as it comes to the true edge of the solar system, where the "wind" of particles blowing out from the Sun is no longer steady - and sometimes is overcome by the cosmic winds of the wider galaxy, actually gusting back on the outward-bound probecraft.
"Voyager tells us now that we're in a stagnation region in the outermost layer of the bubble around our solar system," says Stone.
"We've been using the flow of energetic charged particles at Voyager 1 as a kind of wind sock to estimate the solar wind velocity," says his fellow Voyager scientist Rob Decker. "We've found that the wind speeds are low in this region and gust erratically. For the first time, the wind even blows back at us. We are evidently traveling in completely new territory. Scientists had suggested previously that there might be a stagnation layer, but we weren't sure it existed until now."
According to a NASA statement issued yesterday:
Voyager has been measuring energetic particles that originate from inside and outside our solar system. Until mid-2010, the intensity of particles originating from inside our solar system had been holding steady. But during the past year, the intensity of these energetic particles has been declining, as though they are leaking out into interstellar space. The particles are now half as abundant as they were during the previous five years.
At the same time, Voyager has detected a 100-fold increase in the intensity of high-energy electrons from elsewhere in the galaxy diffusing into our solar system from outside, which is another indication of the approaching boundary.
Voyager 1 was launched stop a Titan/Centaur rocket stack on 5 September 1977, just two weeks after its companion craft Voyager 2 (launched on 20 August 1977), designed to take advantage of a rare conjunction among the outer planets which would let them make a lot of visits there over a relatively short time without much fuel. The two craft made many discoveries, and Voyager 2 remains the only spacecraft ever known to have visited the outer planets Uranus and Neptune.
But in 1989 their work among the planets was done and the two craft were formally tasked to head out into the interstellar void. For the past 22 years they have been not merely space probes but star probes. Voyager 1, the furthest out, is now some 11 billion miles out, almost 120 times as far from the Sun as Earth and several times as far out as Pluto. Voyager 2 is not far behind at 9 billion miles.
Despite their great longevity, the two craft still each generate more than 300 watts of power from their nuclear radioisotope generators, enough to maintain communications and control, and keep some instruments in operation. NASA's Deep Space Network ground stations around the world are in touch with them 8-12 hours a day. The Voyagers' data links deliver upload rates of 16 bits/second, and download at 160 bits/sec (or 1.4 kbps for high-rate plasma data). When out of communication with Earth, the probes store information on an 8-track digital tape recorder.
There's more on the latest from Voyager 1 here [ http://www.jpl.nasa.gov/news/news.cfm?release=2011-372 (latter below)] and more on the Voyagers in general here [ http://voyager.jpl.nasa.gov/index.html ].
Copyright 2011 The Register
http://www.theregister.co.uk/2011/12/06/voyager_edge_interstellar_space/ [comments at http://forums.theregister.co.uk/forum/1/2011/12/06/voyager_edge_interstellar_space/ ]
===
Voyager on the cusp of entering interstellar space
Artist's concept of the positions of Voyager 1 and Voyager 2 moving away from the sun.
Credit: NASA/JPL-Caltech
Artist's concept of a Voyager probe.
Credit: NASA/JPL-Caltech
BY STEPHEN CLARK
SPACEFLIGHT NOW
Posted: December 6, 2011
Plowing through the solar system's unexplored frontier, NASA's Voyager 1 spacecraft has entered a region of stagnant solar wind and magnetic pressure and is on the precipice of crossing over into interstellar space, scientists said Monday.
But estimates for when the nuclear-powered probe will break through are not precise. Ed Stone, Voyager's project scientist, said it could be any time between a few months and a few years from now.
"I can almost assure you that will be confused when this first happens because this will not be simple," Stone said. "Nature tends to be much more creative than our own minds."
Moving around the perimeter of the Milky Way galaxy, the sun generates a wind of charged particles moving out in all directions. Ahead of the sun, the solar wind is compressed like the waves in front of a moving ship by a steady flow of plasma emanating from outside the solar system. The solar particles are mostly diverted down and up, then behind the sun like a ship's wake or a comet's tail.
The region of the sun's influence, in which the solar wind is dominant, is called the heliosphere. The heliopause is the boundary between the heliosphere and interstellar space.
No spacecraft has ever left the solar system before, so Voyager 1 is flying through an uncharted void between the influence of the sun and the interstellar wind, which blows waves of plasma and charged particles at a clip of up to 15 miles per second.
"That transition may not be instantaneous," Stone said. "It may take us months to get through a rather messy interface between these two winds."
The latest data from Voyager 1 show the spacecraft is in a region of stagnation, where the stream of charged particles from the sun has slowed and the sun's magnetic field has piled up, researchers said at the American Geophysical Union's fall meeting in San Francisco.
"We've been using the flow of energetic charged particles at Voyager 1 as a kind of wind sock to estimate the solar wind velocity," said Rob Decker, a co-investigator for Voyager's low-energy charged particle instrument at the Johns Hopkins University Applied Physics Laboratory. "We've found that the wind speeds are low in this region and gust erratically. For the first time, the wind even blows back at us. We are evidently traveling in completely new territory. Scientists had suggested previously that there might be a stagnation layer, but we weren't sure it existed until now."
High-energy electrons from interstellar space are also leaking into the heliosphere, Stone said.
Voyager 1 is now stationed 11 billion miles from the sun.
"What we're talking about today with all these new developements is simply one more chapter in a scientific inquiry that began over 100 years ago," said Eugene Parker, professor emeritus of physics at the University of Chicago.
Looking for signs that the probe has crossed over the heliopause and left the solar system, scientists are closely watching data from Voyager 1's low-energy charged particle counter and magnetic field, cosmic ray and plasma wave instruments.
The twin Voyager 2 probe is about 2 billion miles behind Voyager 1, but it's exploring the southern hemisphere of the heliosphere. Voyager 1 is flying up and out relative to the sun.
The spacecraft have enough power to continue scientific investigations until approximately 2020, according to Stone. The probes could remain functional until around 2025.
Stone said he expects the magnetic field to switch from an east-west to a north-south orientation. Evidence should also show up from more intense low-energy galactic cosmic radiation and reduced intensity of charged particles originating from the sun.
"I think it's reasonable to think it could only be a matter of months or a matter of several years before we cross this region," Stone said. "But no spacecraft has ever been there before and we continue to find our models need to be improved as we learn more about the complex interaction between the solar wind and the interstellar wind."
Traveling a billion miles every three years, the Voyager probes won't reach the vicinity of another star for another 40,000 years.
Both missions launched on Titan-Centaur rockets in 1977. Voyager 2 completed a tour of the outer solar system, flying by Jupiter, Saturn, Uranus and Neptune before heading toward interstellar space.
Voyager 1 studied Jupiter and Saturn in 1979 and 1980.
"To me, it's been constant [discovery]," Parker said. "I hold my breath as to what's going to happen next."
© 2011 Spaceflight Now Inc.
http://www.spaceflightnow.com/news/n1112/06voyager/ [with comments]
===
NASA's Voyager Hits New Region at Solar System Edge
Voyager 1 Encounters Stagnation Region
NASA's Voyager 1 spacecraft has entered a new region between our solar system and interstellar space, which scientists are calling the stagnation region. In the stagnation region, the wind of charged particles streaming out from our sun has slowed and turned inward for the first time, our solar system's magnetic field has piled up and higher-energy particles from inside our solar system appear to be leaking out into interstellar space. This image shows that the inner edge of the stagnation region is located about 113 astronomical units (10.5 billion miles or 16.9 billion kilometers) from the sun. Voyager 1 is currently about 119 astronomical units (11 billion miles or 17.8 billion kilometers) from the sun. The distance to the outer edge is unknown.
Image credit: NASA/JPL-Caltech
2011-372
December 05, 2011
PASADENA, Calif. -- NASA's Voyager 1 spacecraft has entered a new region between our solar system and interstellar space. Data obtained from Voyager over the last year reveal this new region to be a kind of cosmic purgatory. In it, the wind of charged particles streaming out from our sun has calmed, our solar system's magnetic field is piled up, and higher-energy particles from inside our solar system appear to be leaking out into interstellar space.
"Voyager tells us now that we're in a stagnation region in the outermost layer of the bubble around our solar system," said Ed Stone, Voyager project scientist at the California Institute of Technology in Pasadena. "Voyager is showing that what is outside is pushing back. We shouldn't have long to wait to find out what the space between stars is really like."
Although Voyager 1 is about 11 billion miles (18 billion kilometers) from the sun, it is not yet in interstellar space. In the latest data, the direction of the magnetic field lines has not changed, indicating Voyager is still within the heliosphere, the bubble of charged particles the sun blows around itself. The data do not reveal exactly when Voyager 1 will make it past the edge of the solar atmosphere into interstellar space, but suggest it will be in a few months to a few years.
The latest findings, described today at the American Geophysical Union's fall meeting in San Francisco, come from Voyager's Low Energy Charged Particle instrument, Cosmic Ray Subsystem and Magnetometer.
Scientists previously reported the outward speed of the solar wind had diminished to zero in April 2010, marking the start of the new region. Mission managers rolled the spacecraft several times this spring and summer to help scientists discern whether the solar wind was blowing strongly in another direction. It was not. Voyager 1 is plying the celestial seas in a region similar to Earth's doldrums, where there is very little wind.
During this past year, Voyager's magnetometer also detected a doubling in the intensity of the magnetic field in the stagnation region. Like cars piling up at a clogged freeway off-ramp, the increased intensity of the magnetic field shows that inward pressure from interstellar space is compacting it.
Voyager has been measuring energetic particles that originate from inside and outside our solar system. Until mid-2010, the intensity of particles originating from inside our solar system had been holding steady. But during the past year, the intensity of these energetic particles has been declining, as though they are leaking out into interstellar space. The particles are now half as abundant as they were during the previous five years.
At the same time, Voyager has detected a 100-fold increase in the intensity of high-energy electrons from elsewhere in the galaxy diffusing into our solar system from outside, which is another indication of the approaching boundary.
"We've been using the flow of energetic charged particles at Voyager 1 as a kind of wind sock to estimate the solar wind velocity," said Rob Decker, a Voyager Low-Energy Charged Particle Instrument co-investigator at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. "We've found that the wind speeds are low in this region and gust erratically. For the first time, the wind even blows back at us. We are evidently traveling in completely new territory. Scientists had suggested previously that there might be a stagnation layer, but we weren't sure it existed until now."
Launched in 1977, Voyager 1 and 2 are in good health. Voyager 2 is 9 billion miles (15 billion kilometers) away from the sun.
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. For more information about the Voyager spacecraft, visit: http://www.nasa.gov/voyager .
For more information about NASA media events at the American Geophysical Union meeting, visit: http://www.nasa.gov/agu .
Jia-Rui C. Cook/Alan Buis 818-354-0850/818-653-8339
Jet Propulsion Laboratory, Pasadena, Calif.
jccook@jpl.nasa.gov/alan.d.buis@jpl.nasa.gov
Steve Cole 202-358-0918
NASA Headquarters, Washington
stephen.e.cole@nasa.gov
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=69673154
===
(linked in):
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=62558791 (and preceding and following)
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=68965601 and following
Her 39-year-and-counting mission ... to boldly go
'Soon we find out what interstellar space is really like'
By Lewis Page
Posted in Space, 6th December 2011 08:46 GMT
NASA's famous Voyager 1 space probe, sailing outwards into the interstellar void far beyond the orbit of Pluto, has entered a new and never-before-seen region of space thought to be the very edge of the "bubble" maintained around the solar system by the power of the Sun.
"We shouldn't have long to wait to find out what the space between stars is really like," enthuses Ed Stone, Voyager project boffin.
The probe has been encountering strange, previously unseen phenomena in recent times as it comes to the true edge of the solar system, where the "wind" of particles blowing out from the Sun is no longer steady - and sometimes is overcome by the cosmic winds of the wider galaxy, actually gusting back on the outward-bound probecraft.
"Voyager tells us now that we're in a stagnation region in the outermost layer of the bubble around our solar system," says Stone.
"We've been using the flow of energetic charged particles at Voyager 1 as a kind of wind sock to estimate the solar wind velocity," says his fellow Voyager scientist Rob Decker. "We've found that the wind speeds are low in this region and gust erratically. For the first time, the wind even blows back at us. We are evidently traveling in completely new territory. Scientists had suggested previously that there might be a stagnation layer, but we weren't sure it existed until now."
According to a NASA statement issued yesterday:
Voyager has been measuring energetic particles that originate from inside and outside our solar system. Until mid-2010, the intensity of particles originating from inside our solar system had been holding steady. But during the past year, the intensity of these energetic particles has been declining, as though they are leaking out into interstellar space. The particles are now half as abundant as they were during the previous five years.
At the same time, Voyager has detected a 100-fold increase in the intensity of high-energy electrons from elsewhere in the galaxy diffusing into our solar system from outside, which is another indication of the approaching boundary.
Voyager 1 was launched stop a Titan/Centaur rocket stack on 5 September 1977, just two weeks after its companion craft Voyager 2 (launched on 20 August 1977), designed to take advantage of a rare conjunction among the outer planets which would let them make a lot of visits there over a relatively short time without much fuel. The two craft made many discoveries, and Voyager 2 remains the only spacecraft ever known to have visited the outer planets Uranus and Neptune.
But in 1989 their work among the planets was done and the two craft were formally tasked to head out into the interstellar void. For the past 22 years they have been not merely space probes but star probes. Voyager 1, the furthest out, is now some 11 billion miles out, almost 120 times as far from the Sun as Earth and several times as far out as Pluto. Voyager 2 is not far behind at 9 billion miles.
Despite their great longevity, the two craft still each generate more than 300 watts of power from their nuclear radioisotope generators, enough to maintain communications and control, and keep some instruments in operation. NASA's Deep Space Network ground stations around the world are in touch with them 8-12 hours a day. The Voyagers' data links deliver upload rates of 16 bits/second, and download at 160 bits/sec (or 1.4 kbps for high-rate plasma data). When out of communication with Earth, the probes store information on an 8-track digital tape recorder.
There's more on the latest from Voyager 1 here [ http://www.jpl.nasa.gov/news/news.cfm?release=2011-372 (latter below)] and more on the Voyagers in general here [ http://voyager.jpl.nasa.gov/index.html ].
Copyright 2011 The Register
http://www.theregister.co.uk/2011/12/06/voyager_edge_interstellar_space/ [comments at http://forums.theregister.co.uk/forum/1/2011/12/06/voyager_edge_interstellar_space/ ]
===
Voyager on the cusp of entering interstellar space
Artist's concept of the positions of Voyager 1 and Voyager 2 moving away from the sun.
Credit: NASA/JPL-Caltech
Artist's concept of a Voyager probe.
Credit: NASA/JPL-Caltech
BY STEPHEN CLARK
SPACEFLIGHT NOW
Posted: December 6, 2011
Plowing through the solar system's unexplored frontier, NASA's Voyager 1 spacecraft has entered a region of stagnant solar wind and magnetic pressure and is on the precipice of crossing over into interstellar space, scientists said Monday.
But estimates for when the nuclear-powered probe will break through are not precise. Ed Stone, Voyager's project scientist, said it could be any time between a few months and a few years from now.
"I can almost assure you that will be confused when this first happens because this will not be simple," Stone said. "Nature tends to be much more creative than our own minds."
Moving around the perimeter of the Milky Way galaxy, the sun generates a wind of charged particles moving out in all directions. Ahead of the sun, the solar wind is compressed like the waves in front of a moving ship by a steady flow of plasma emanating from outside the solar system. The solar particles are mostly diverted down and up, then behind the sun like a ship's wake or a comet's tail.
The region of the sun's influence, in which the solar wind is dominant, is called the heliosphere. The heliopause is the boundary between the heliosphere and interstellar space.
No spacecraft has ever left the solar system before, so Voyager 1 is flying through an uncharted void between the influence of the sun and the interstellar wind, which blows waves of plasma and charged particles at a clip of up to 15 miles per second.
"That transition may not be instantaneous," Stone said. "It may take us months to get through a rather messy interface between these two winds."
The latest data from Voyager 1 show the spacecraft is in a region of stagnation, where the stream of charged particles from the sun has slowed and the sun's magnetic field has piled up, researchers said at the American Geophysical Union's fall meeting in San Francisco.
"We've been using the flow of energetic charged particles at Voyager 1 as a kind of wind sock to estimate the solar wind velocity," said Rob Decker, a co-investigator for Voyager's low-energy charged particle instrument at the Johns Hopkins University Applied Physics Laboratory. "We've found that the wind speeds are low in this region and gust erratically. For the first time, the wind even blows back at us. We are evidently traveling in completely new territory. Scientists had suggested previously that there might be a stagnation layer, but we weren't sure it existed until now."
High-energy electrons from interstellar space are also leaking into the heliosphere, Stone said.
Voyager 1 is now stationed 11 billion miles from the sun.
"What we're talking about today with all these new developements is simply one more chapter in a scientific inquiry that began over 100 years ago," said Eugene Parker, professor emeritus of physics at the University of Chicago.
Looking for signs that the probe has crossed over the heliopause and left the solar system, scientists are closely watching data from Voyager 1's low-energy charged particle counter and magnetic field, cosmic ray and plasma wave instruments.
The twin Voyager 2 probe is about 2 billion miles behind Voyager 1, but it's exploring the southern hemisphere of the heliosphere. Voyager 1 is flying up and out relative to the sun.
The spacecraft have enough power to continue scientific investigations until approximately 2020, according to Stone. The probes could remain functional until around 2025.
Stone said he expects the magnetic field to switch from an east-west to a north-south orientation. Evidence should also show up from more intense low-energy galactic cosmic radiation and reduced intensity of charged particles originating from the sun.
"I think it's reasonable to think it could only be a matter of months or a matter of several years before we cross this region," Stone said. "But no spacecraft has ever been there before and we continue to find our models need to be improved as we learn more about the complex interaction between the solar wind and the interstellar wind."
Traveling a billion miles every three years, the Voyager probes won't reach the vicinity of another star for another 40,000 years.
Both missions launched on Titan-Centaur rockets in 1977. Voyager 2 completed a tour of the outer solar system, flying by Jupiter, Saturn, Uranus and Neptune before heading toward interstellar space.
Voyager 1 studied Jupiter and Saturn in 1979 and 1980.
"To me, it's been constant [discovery]," Parker said. "I hold my breath as to what's going to happen next."
© 2011 Spaceflight Now Inc.
http://www.spaceflightnow.com/news/n1112/06voyager/ [with comments]
===
NASA's Voyager Hits New Region at Solar System Edge
Voyager 1 Encounters Stagnation Region
NASA's Voyager 1 spacecraft has entered a new region between our solar system and interstellar space, which scientists are calling the stagnation region. In the stagnation region, the wind of charged particles streaming out from our sun has slowed and turned inward for the first time, our solar system's magnetic field has piled up and higher-energy particles from inside our solar system appear to be leaking out into interstellar space. This image shows that the inner edge of the stagnation region is located about 113 astronomical units (10.5 billion miles or 16.9 billion kilometers) from the sun. Voyager 1 is currently about 119 astronomical units (11 billion miles or 17.8 billion kilometers) from the sun. The distance to the outer edge is unknown.
Image credit: NASA/JPL-Caltech
2011-372
December 05, 2011
PASADENA, Calif. -- NASA's Voyager 1 spacecraft has entered a new region between our solar system and interstellar space. Data obtained from Voyager over the last year reveal this new region to be a kind of cosmic purgatory. In it, the wind of charged particles streaming out from our sun has calmed, our solar system's magnetic field is piled up, and higher-energy particles from inside our solar system appear to be leaking out into interstellar space.
"Voyager tells us now that we're in a stagnation region in the outermost layer of the bubble around our solar system," said Ed Stone, Voyager project scientist at the California Institute of Technology in Pasadena. "Voyager is showing that what is outside is pushing back. We shouldn't have long to wait to find out what the space between stars is really like."
Although Voyager 1 is about 11 billion miles (18 billion kilometers) from the sun, it is not yet in interstellar space. In the latest data, the direction of the magnetic field lines has not changed, indicating Voyager is still within the heliosphere, the bubble of charged particles the sun blows around itself. The data do not reveal exactly when Voyager 1 will make it past the edge of the solar atmosphere into interstellar space, but suggest it will be in a few months to a few years.
The latest findings, described today at the American Geophysical Union's fall meeting in San Francisco, come from Voyager's Low Energy Charged Particle instrument, Cosmic Ray Subsystem and Magnetometer.
Scientists previously reported the outward speed of the solar wind had diminished to zero in April 2010, marking the start of the new region. Mission managers rolled the spacecraft several times this spring and summer to help scientists discern whether the solar wind was blowing strongly in another direction. It was not. Voyager 1 is plying the celestial seas in a region similar to Earth's doldrums, where there is very little wind.
During this past year, Voyager's magnetometer also detected a doubling in the intensity of the magnetic field in the stagnation region. Like cars piling up at a clogged freeway off-ramp, the increased intensity of the magnetic field shows that inward pressure from interstellar space is compacting it.
Voyager has been measuring energetic particles that originate from inside and outside our solar system. Until mid-2010, the intensity of particles originating from inside our solar system had been holding steady. But during the past year, the intensity of these energetic particles has been declining, as though they are leaking out into interstellar space. The particles are now half as abundant as they were during the previous five years.
At the same time, Voyager has detected a 100-fold increase in the intensity of high-energy electrons from elsewhere in the galaxy diffusing into our solar system from outside, which is another indication of the approaching boundary.
"We've been using the flow of energetic charged particles at Voyager 1 as a kind of wind sock to estimate the solar wind velocity," said Rob Decker, a Voyager Low-Energy Charged Particle Instrument co-investigator at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. "We've found that the wind speeds are low in this region and gust erratically. For the first time, the wind even blows back at us. We are evidently traveling in completely new territory. Scientists had suggested previously that there might be a stagnation layer, but we weren't sure it existed until now."
Launched in 1977, Voyager 1 and 2 are in good health. Voyager 2 is 9 billion miles (15 billion kilometers) away from the sun.
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. For more information about the Voyager spacecraft, visit: http://www.nasa.gov/voyager .
For more information about NASA media events at the American Geophysical Union meeting, visit: http://www.nasa.gov/agu .
Jia-Rui C. Cook/Alan Buis 818-354-0850/818-653-8339
Jet Propulsion Laboratory, Pasadena, Calif.
jccook@jpl.nasa.gov/alan.d.buis@jpl.nasa.gov
Steve Cole 202-358-0918
NASA Headquarters, Washington
stephen.e.cole@nasa.gov
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=69673154
===
(linked in):
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=62558791 (and preceding and following)
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=68965601 and following
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