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mood posted a topic in General NewsIn the emptiness of space, Voyager 1 detects plasma ‘hum’ NASA/JPL/Provided In an artist's depiction, the Voyager 1 craft continues to cruise through interstellar space. Voyager 1 – one of two sibling NASA spacecraft launched 44 years ago and now the most distant human-made object in space – still works and zooms toward infinity. As the craft toils, it has long since zipped past the edge of the solar system through the heliopause – the solar system’s border with interstellar space – into the interstellar medium. Now, its instruments have detected the constant drone of interstellar gas (plasma waves), according to Cornell-led research published May 10 in Nature Astronomy. Examining data slowly sent back from more than 14 billion miles away, Stella Koch Ocker, a Cornell doctoral student in astronomy, has uncovered the emission. “It’s very faint and monotone, because it is in a narrow frequency bandwidth,” Ocker said. “We’re detecting the faint, persistent hum of interstellar gas.” This work allows scientists to understand how the interstellar medium interacts with the solar wind, Ocker said, and how the protective bubble of the solar system’s heliosphere is shaped and modified by the interstellar environment. Launched in September 1977, the Voyager 1 spacecraft flew by Jupiter in 1979 and then Saturn in late 1980. Travelling at about 38,000 mph, Voyager 1 crossed the heliopause in August 2012. After entering interstellar space, the spacecraft’s Plasma Wave System detected perturbations in the gas. But, in between those eruptions – caused by our own roiling sun – researchers have uncovered a steady, persistent signature produced by the tenuous near-vacuum of space. ”The interstellar medium is like a quiet or gentle rain,” said senior author James Cordes, the George Feldstein Professor of Astronomy (A&S). “In the case of a solar outburst, it’s like detecting a lightning burst in a thunderstorm and then it’s back to a gentle rain.” Ocker believes there is more low-level activity in the interstellar gas than scientists had previously thought, which allows researchers to track the spatial distribution of plasma – that is, when it’s not being perturbed by solar flares. Cornell research scientist Shami Chatterjee explained how continuous tracking of the density of interstellar space is important. “We’ve never had a chance to evaluate it. Now we know we don’t need a fortuitous event related to the sun to measure interstellar plasma,” Chatterjee said. “Regardless of what the sun is doing, Voyager is sending back detail. The craft is saying, ‘Here’s the density I'm swimming through right now. And here it is now. And here it is now. And here it is now.’ Voyager is quite distant and will be doing this continuously.” Voyager 1 left Earth carrying a Golden Record created by a committee chaired by the late Cornell professor Carl Sagan, as well as mid-1970s technology. “Scientifically, this research is quite a feat. It’s a testament to the amazing Voyager spacecraft,” Ocker said. “It’s the engineering gift to science that keeps on giving.” In addition to Ocker, Cordes and Chatterjee, the paper, “Persistent plasma waves in interstellar space detected by Voyager 1,” was co-authored by professor emeritus Donald A. Gurnett, the principal investigator on the plasma wave system (PWS) on both Voyager spacecraft; Steven R. Spangler, professor; and research scientist William S. Kurth, co-investigator on PWS, all from the University of Iowa. NASA, the Jet Propulsion Laboratory and the National Science Foundation supported the work. Cordes, Chatterjee and Ockler are members of Cornell’s Carl Sagan Institute. Source: In the emptiness of space, Voyager 1 detects plasma ‘hum’
CNN) -- Hurtling across the Milky Way like an eternal explorer -- the Voyager 1 spacecraft continues to nonchalantly reveal the mysteries of the solar system to a captivated Earthbound audience. Active volcanoes, methane rain, icy geysers and intricate details about Saturn's rings -- the list of revelations attributed to the mission reads like fantastical sci-fi novel but it has revolutionized planetary astronomy. Thirty-seven years after it launched, Voyager 1 is still out in the vast expanse of space, periodically relaying new data back home. But in 2013, NASA made the groundbreaking announcement that Voyager 1 had left the heliosphere -- a magnetic boundary "bubble," if you will, which scientists use to explain the separation of our solar system from the rest of the galaxy. "That means Voyager has traveled outside the bubble of our sun," explains Voyager project manager Suzy Dodd. "The data Voyager 1 sends us now is data from other stars and from super nova eruptions and the remnant of stars that have exploded over the course of history." It's an incredible achievement for a probe built for an initial five-year mission. But now, not for the first time since the extraordinary statement, doubts have been cast on whether the craft has actually made the historic crossing. While measurements allowed NASA to feel confident enough to confirm Voyager 1 had entered interstellar space, two University of Michigan scientists who have worked on the Voyager missions remain skeptical. Reliving the moon landing Solar flares caught on camera Zero gravity training with NASA Maneuvering NASA's Curiosity rover "This controversy will continue until it is resolved by measurements," said George Gloeckler, a University of Michigan professor of atmospheric, oceanic and space sciences, and lead author of a new study, in an American Geophysical Union press release. SEE: Moon maps through the ages To that end, Gloeckler and fellow University of Michigan professor and study co-author Len Fisk, predict that when Voyager does cross the threshold into interstellar space, the probe will identify a reversal in the magnetic field, which will be relayed back to scientists on Earth, conclusively determining the spacecraft's location. They expect this magnetic field shift to occur in the next two years, and if it doesn't, this would confirm that Voyager 1 has already left the heliosphere. But while we may not know the exact location of Voyager 1, we do know that it's one of the most successful spacecraft of all time. 'The little spacecraft that could' Launched individually in the summer of 1977, Voyager was a twin-spacecraft primary mission developed by NASA to explore Jupiter and Saturn and their larger moons. Following successful completion of the Voyager mission's primary objectives, a rare planetary alignment offered up remarkable opportunities for the two craft to continue space exploration. "Voyager took advantage of alignment of the outer planets, which are Jupiter, Saturn, Uranus and Neptune, to be able to go by all four of those planets in a 12-year period. That alignment of planets only happens every 176 years," says Dodd -- who has described Voyager 1 as "the little spacecraft that could." "The data Voyager 1 sends us now is data from other stars ... that have exploded over the course of history. Voyager project manager Suzy Dodd So in 1980 the Voyager mission was officially extended and renamed the Interstellar mission. The probes were now participating in an exploratory odyssey to the farthest reaches of the heliosphere ... and beyond. Through remote-control reprogramming -- a technological advancement unavailable at launch -- using Saturn's gravitational field, the Voyager 1 probe was fired like a slingshot on a trajectory that would take it onwards into interstellar space. Meanwhile Voyager 2 was redirected onto a new flight path, taking in the sights of Neptune and Uranus, before it will eventually follow its counterpart out of the heliosphere. To this day, it remains the only man-made object to have visited Neptune and Uranus. Not bad for vintage technology that has just 70 kilobytes of memory on board; a 16 gigabyte iPhone 5 has more than 240,000 times that amount. Voyager 1 is now so far from Earth that commands take more than 17 hours to reach it. But it will be a little while before the spacecraft will encounter any more planets. "It is going to take us 40,000 years to come within three light years of the next nearest sun or the next nearest star," says Dodd. "And that is a long, long time." original article: http://edition.cnn.com/2014/08/01/tech/innovation/voyager-1-little-spacecraft-that-could/index.html