Using a computer model simulation, Haruichi Washimi, a physicist at UC Riverside, has predicted when the interplanetary spacecraft Voyager 2 will cross the “termination shock,” the spherical shell around the solar system that marks where the solar wind slows down to subsonic speed.
According to Washimi’s simulations, the spacecraft is set to cross the termination shock in late 2007-early 2008. To make this forecast, Washimi and his colleagues used data from Voyager 2 and performed a global “magneto-hydrodynamic simulation” – a method that allows for precise and quantitative predictions of geomagnetic disturbances caused by solar activities.
Because Voyager 2’s crossing of the shock is expected to be an abrupt and relatively brief event, scientists are working to ensure that the most is made of the opportunity. With an idea of when the spacecraft will cross the shock, they are better able to maximize coverage of the crossing.
Study results appear in the Dec. 1 issue of The Astrophysical Journal.
“Washimi’s model has predicted the location of a boundary that is approximately 90 times farther from the sun than is the Earth, to within a few percent,” said Gary Zank, the director of the Institute of Geophysics and Planetary Physics and one of the coauthors of the research paper. “This is truly remarkable given the enormous complexity of the physics involved, the temporal and spatial scales involved, and the variability of the solar wind conditions.”
The solar wind – a stream of charged particles ejected by the sun in all directions – travels at supersonic speeds when it leaves the sun, until it eventually encounters the interstellar medium made up of plasma, neutral gas and dust.
At the termination shock, located at 7-8.5 billion miles from the sun, the solar wind is decelerated to less than the speed of sound. The boundary of the termination shock is not fixed, however, but wobbly, fluctuating in both time and distance from the sun, depending on solar activity.
“This is the first time the termination-shock position has been forecast in this way,” said Washimi, the lead author of the research paper and a scientist at the Institute of Geophysics and Planetary Physics. “After it crosses this boundary, Voyager 2 will be in the outer heliosphere beyond which lies the interstellar medium and galactic space. Our simulations also show that the spacecraft will cross the termination shock again in the middle of 2008. This will happen because of the back and forth movement of the termination-shock boundary. This means Voyager 2 will experience multiple crossings of the termination shock. These crossings will come to an end after the spacecraft escapes into galactic space.”
Voyager 2 was launched Aug. 20, 1977. It visited four planets and their moons in the course of its journey into space. Its sister spacecraft Voyager 1, which was launched Sept. 5, 1977, crossed the termination shock in December 2004 – earlier than Voyager 2 because of a shorter trajectory. Both spacecraft are currently operational, but power sources have degraded and some of the instrumentation no longer works optimally. In the future, the spacecraft will encounter their next milestone in space: the heliopause, which is the boundary where the interstellar medium brings the solar wind to a halt.
Iqbal Pittalwala | EurekAlert!
UNH scientists help provide first-ever views of elusive energy explosion
16.11.2018 | University of New Hampshire
NASA keeps watch over space explosions
16.11.2018 | NASA/Goddard Space Flight Center
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
09.11.2018 | Event News
06.11.2018 | Event News
23.10.2018 | Event News
16.11.2018 | Physics and Astronomy
16.11.2018 | Physics and Astronomy
16.11.2018 | Life Sciences