Computer simulation predicts Voyager 2 will reach major milestone in space in late 2007-early 2008November 28, 2007According to UC Riverside physicist's model, spacecraft will cross 'termination shock' one more time, in mid-2008 RIVERSIDE, Calif. - 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. University of California - Riverside |
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| Related Voyager Current Events and Voyager News Articles A Long Night Falls Over Saturn's Rings As Saturn's rings orbit the planet, a section is typically in the planet's shadow, experiencing a brief night lasting from 6 to 14 hours. However, once approximately every 15 years, night falls over the entire visible ring system for about four days. NAE announces award winners John Casani and Sheila Widnall During its 2009 annual meeting, the National Academy of Engineering (NAE) will present two awards for extraordinary impacts on the engineering profession. New technique could find water on Earth-like planets orbiting distant suns Since the early 1990s astronomers have discovered more than 300 planets orbiting stars other than our sun, nearly all of them gas giants like Jupiter. Cost of hatchling turtles' dash for freedom A newly hatched sea turtle's first swim is the most critical of its life. Having run the gauntlet of air and land predators to make it to the sea, the tiny voyager must also evade hungry fish patrolling the beaches in its bid for freedom. NASA spacecraft ready to explore outer solar system The first NASA spacecraft to image and map the dynamic interactions taking place where the hot solar wind slams into the cold expanse of space is ready for launch Oct. 19. The two-year mission will begin from the Kwajalein Atoll, a part of the Marshall Islands in the Pacific Ocean. Stellar still births The systematics of celestial bodies apparently needs to be revised. Researchers at the Argelander Institute of Astronomy of the University of Bonn have discovered that brown dwarfs need to be treated as a separate class in addition to stars and planets. Hubble, Keck images show continued turbulence in Jupiter's atmosphere Increased turbulence and storms first observed on Jupiter more than two years ago are still raging, according to astronomers from the University of California, Berkeley, and the W. M. Keck Observatory in Hawaii, who snapped high-resolution pictures of the planet earlier this month. Storm Winds Blow in Jupiter's Little Red Spot Using data from NASA's New Horizons spacecraft and two telescopes at Earth, an international team of scientists has found that one of the solar system's largest and newest storms - Jupiter's Little Red Spot - has some of the highest wind speeds ever detected on any planet. Voyager 2 Proves the Solar System is Squashed NASA's Voyager 2 spacecraft has followed its twin Voyager 1 into the solar system's final frontier, a vast region at the edge of our solar system where the solar wind runs up against the thin gas between the stars. Astronomers get first look at Uranus's rings as they swing edge-on to Earth As the rings of Uranus swing edge-on to Earth - a short-lived view we get only once every 42 years - astronomers observing the event are getting an unprecedented, glare-free view of the rings and the fine dust that permeates them. More Voyager Current Events and Voyager News Articles |
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