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Posts Tagged ‘heliosphere’

A New View Of The Solar System: Astrophysical Jets Driven By The Sun

February 19, 2015 Leave a comment

As the sun skims through the galaxy, it flings out charged particles in a stream of plasma called the solar wind, and the solar wind creates a bubble extending far outside the solar system known as the heliosphere. For decades, scientists have visualized the heliosphere as shaped like a comet, with a very long tail extending thousands of times as far as the distance from the Earth to the sun.

New research suggests that the sun’s magnetic field controls the large-scale shape of the heliosphere “much more than had been previously thought,” says Merav Opher, associate professor of astronomy and director of the Center for Space Physics at Boston University (BU). In the new model, the magnetic field squeezes the solar wind along the sun’s North and South axes, producing two jets that are then dragged downstream by the flow of the interstellar medium through which the heliosphere moves.

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NASA Voyager: ‘Tsunami Wave’ Still Flies Through Interstellar Space

December 16, 2014 Leave a comment

Artist's concept. Image credit: NASA/JPL-Caltech

Artist’s concept. Image credit: NASA/JPL-Caltech

• The Voyager 1 spacecraft has experienced three shock waves

• The most recent shock wave, first observed in February 2014, still appears to be going on

• One wave, previously reported, helped researchers determine that Voyager 1 had entered interstellar space

The “tsunami wave” that NASA’s Voyager 1 spacecraft began experiencing earlier this year is still propagating outward, according to new results. It is the longest-lasting shock wave that researchers have seen in interstellar space.

“Most people would have thought the interstellar medium would have been smooth and quiet. But these shock waves seem to be more common than we thought,” said Don Gurnett, professor of physics at the University of Iowa in Iowa City. Gurnett presented the new data Monday, Dec. 15 at the American Geophysical Union meeting in San Francisco.

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Voyager Spacecraft Might Not Have Reached Interstellar Space


In 2012, the Voyager mission team announced that the Voyager 1 spacecraft had passed into interstellar space, traveling further from Earth than any other manmade object.

But, in the nearly two years since that historic announcement, and despite subsequent observations backing it up, uncertainty about whether Voyager 1 really crossed the threshold continues. There are some scientists who say that the spacecraft is still within the heliosphere – the region of space dominated by the Sun and its wind of energetic particles – and has not yet reached the space between the stars.

Now, two Voyager team scientists have developed a test that they say could prove once and for all if Voyager 1 has crossed the boundary. The new test is outlined in a study accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union.

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IBEX Research Shows Influence Of Galactic Magnetic Field Extends Well Beyond Our Solar System

February 13, 2014 Leave a comment

In a report published today, new research suggests the enigmatic “ribbon” of energetic particles discovered at the edge of our solar system by NASA’s Interstellar Boundary Explorer (IBEX) may be only a small sign of the vast influence of the galactic magnetic field.

IBEX researchers have sought answers about the ribbon since its discovery in 2009. Comprising primarily space physicists, the IBEX team realized that the galactic magnetic field wrapped around our heliosphere — the giant “bubble” that envelops and protects our solar system — appears to determine the orientation of the ribbon and the placement of energetic particles measured in it.

An unlikely teaming of IBEX researchers with ultra-high-energy cosmic ray physicists, however, has produced complementary insights that dovetail with IBEX’s studies to produce a more complete picture of the interactions at the solar system boundary and how they reach much farther out into the space between the stars.

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NASA Voyager Statement About Competing Models To Explain Recent Spacecraft Data

August 16, 2013 Leave a comment

A newly published paper argues that NASA’s Voyager 1 spacecraft has already entered interstellar space. The model described in the paper is new and different from other models used so far to explain the data the spacecraft has been sending back from more than 11 billion miles (18 billion kilometers) away from our sun.

NASA’s Voyager project scientist, Ed Stone of the California Institute of Technology in Pasadena, explains:

“Details of a new model have just been published that lead the scientists who created the model to argue that NASA’s Voyager 1 spacecraft data can be consistent with entering interstellar space in 2012. In describing on a fine scale how magnetic field lines from the sun and magnetic field lines from interstellar space can connect to each other, they conclude Voyager 1 has been detecting the interstellar magnetic field since July 27, 2012. Their model would mean that the interstellar magnetic field direction is the same as that which originates from our sun.

Full Story: http://www.nasa.gov/mission_pages/voyager/voyager20130815.html

IBEX Spacecraft Images The Heliotail


NASA’s Interstellar Boundary Explorer (IBEX) spacecraft recently provided the first complete pictures of the solar system’s downwind region, revealing a unique and unexpected structure.

Researchers have long theorized that, like a comet, a “tail” trails the heliosphere, the giant bubble in which our solar system resides, as the heliosphere moves through interstellar space. The first IBEX images released in 2009 showed an unexpected ribbon of surprisingly high energetic neutral atom (ENA) emissions circling the upwind side of the solar system. With the collection of additional ENAs over the first year of observations, a structure dominated by lower energy ENAs emerged, which was preliminarily identified as the heliotail. However, it was quite small and appeared to be offset from the downwind direction, possibly because of interactions from the galaxy’s external magnetic field.

As the next two years of IBEX data filled in the observational hole in the downwind direction, researchers found a second tail region to the side of the previously identified one. The IBEX team reoriented the IBEX maps and two similar, low-energy ENA structures became clearly visible straddling the downwind direction of the heliosphere, indicating structures that better resemble “lobes” than a single unified tail.

Full Story: http://www.swri.org/9what/releases/2013/ibex-heliotail.htm#.Ud7sxn4o5hE

NASA’s Voyager 1 Explores Final Frontier Of Our ‘Solar Bubble’

July 2, 2013 1 comment

Artist's concept. Image Credit: NASA/JPL-Caltech

Artist’s concept. Image Credit: NASA/JPL-Caltech

Data from Voyager 1, now more than 11 billion miles (18 billion kilometers) from the sun, suggest the spacecraft is closer to becoming the first human-made object to reach interstellar space.

Scientists have seen two of the three signs of interstellar arrival they expected to see: charged particles disappearing as they zoom out along the solar magnetic field, and cosmic rays from far outside zooming in. Scientists have not yet seen the third sign, an abrupt change in the direction of the magnetic field, which would indicate the presence of the interstellar magnetic field.

“This strange, last region before interstellar space is coming into focus, thanks to Voyager 1, humankind’s most distant scout,” said Ed Stone, Voyager project scientist at the California Institute of Technology in Pasadena. “If you looked at the cosmic ray and energetic particle data in isolation, you might think Voyager had reached interstellar space, but the team feels Voyager 1 has not yet gotten there because we are still within the domain of the sun’s magnetic field.”

Full Story: http://www.jpl.nasa.gov/news/news.php?release=2013-209
Also: http://www.jhuapl.edu/newscenter/pressreleases/2013/130627.asp