Voyager spacecraft detects 'persistent hum' beyond our solar system | CNN

Two new missions to Venus -- DAVINCI+ and VERITAS -- have been selected by NASA. These missions will shed light on how Venus became the inhospitable world it is today, despite the fact that it shares many characteristics with Earth.

This illustration shows the position of NASA's Voyager 1 and Voyager 2 probes outside the heliosphere, a protective bubble created by the sun that extends well past the orbit of Pluto.

SPHEREx, the Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer, will study the beginning and evolution of the universe and determine how common the ingredients for life are within the planetary systems found in our galaxy, the Milky Way. It is targeted to launch in 2024.

Caltech

This illustration shows NASA's Dragonfly rotorcraft-lander approaching a site on Saturn's exotic moon, Titan. Taking advantage of Titan's dense atmosphere and low gravity, Dragonfly will explore dozens of locations across the icy world, sampling and measuring the compositions of Titan's organic surface materials to characterize the habitability of Titan's environment and investigate the progression of prebiotic chemistry.

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NASA's Wide Field Infrared Survey Telescope, slated to launch in the mid-2020s, has been named the Nancy Grace Roman Space Telescope, after NASA's first chief astronomer.

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This is an artist's concept of the Europa Clipper spacecraft, which will investigate Jupiter's icy moon.

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Bright swaths of red in the upper atmosphere, known as airglow, can be seen in this image from the International Space Station. NASA's ICON mission will observe how interactions between terrestrial weather and a layer of charged particles called the ionosphere create the colorful glow.

NASA

NASA's Global-scale Observations of the Limb and Disk mission -- known as the GOLD mission -- will examine the response of the upper atmosphere to force from the sun, the magnetosphere and the lower atmosphere.

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NASA's Transiting Exoplanet Survey Satellite launched in April and is already identifying exoplanets orbiting the brightest stars just outside our solar system. In the first three months since it began surveying the sky in July, it has found three exoplanets, with the promise of many more ahead.

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This is an artist's concept of the Solar Probe Plus spacecraft approaching the sun. In order to unlock the mysteries of the corona, but also to protect a society that is increasingly dependent on technology from the threats of space weather, we will send Solar Probe Plus to touch the sun.

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Breakthrough Starshot —

This illustration shows light beams from Earth pushing a tiny spacecraft's sail. The proposed Breakthrough Starshot project would send hundreds of "nanocraft" space probes 4.37 light years away -- at speeds of up to 100 million miles an hour -- to to explore Alpha Centauri, our nearest star system. The ambitious project is many years away from becoming reality.

Courtesy BREAKTHROUGH INITIATIVES

Breakthrough Starshot —

Philanthropist Yuri Milner, left, and astrophysicist Stephen Hawking host a press conference to announce Breakthrough Starshot on Tuesday, April 12, 2016, in New York City. Facebook co-founder Mark Zuckerberg also sits on the mission's board of directors.

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New Horizons —

No spacecraft had ever gone to Pluto before NASA's New Horizons made its fly-by on July 14, 2015. The probe sent back amazing, detailed images of Pluto and its largest moon, Charon. It also dazzled scientists with new information about Pluto's atmosphere and landscape. New Horizons is still going today, heading out into the Kuiper Belt.

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Curiosity Mars Rover —

This image shows the Curiosity rover doing a test drill on a rock dubbed "Bonanza King" to see if it would be a good place to dig deeper and take a sample. Curiosity was launched in 2011, and it is the most advanced rover ever built. It's helping scientists determine whether Mars is, or ever was, habitable for life forms.

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Kepler —

The Kepler space observatory is the first NASA mission dedicated to finding Earth-size planets in or near the habitable zones of stars. Launched in 2009, Kepler has been detecting planets and planet candidates with a wide range of sizes and orbital distances. Yes, we are still finding new planets.

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NEOWISE —

NASA's infrared-wavelength space telescope called NEOWISE may help make us safer. The space telescope hunts for asteroids and comets, including those that could pose a threat to Earth. During its planned three-year survey through 2016, NEOWISE will identify near-Earth objects, gather data on their size and take other measurements. The probe was launched on December 14, 2009, for its original mission -- to perform an all-sky astronomical survey. The probe was put in hibernation for several years, but it was fired up again in December 2013 to hunt for asteroids. Its images are now available to the public online.

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Dawn —

NASA's Dawn spacecraft began orbiting the dwarf planet Ceres in March. Scientists were surprised by the large white spots shining on Ceres, seen above. On its way to Ceres, Dawn spent time studying the proto-planet Vesta in 2001. Ceres and Vesta are the two most massive bodies in the main asteroid belt between Mars and Jupiter. The mission, launched in 2007, is giving scientists new knowledge of how the solar system formed and evolved.

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NASA's <a href="http://www.nasa.gov/mission_pages/deepimpact/main/" target="_blank" target="_blank">Deep Impact spacecraft</a> was launched on January 12, 2005, and it traveled 268 million miles (431 million kilometers) to hurl its coffee table-sized probe into comet Tempel 1 on July 4, 2005. This image of Tempel 1 was taken by Deep Impact's camera 67 seconds after the probe hit the comet. Scattered light from the collision saturated the camera's detector and caused the bright splash seen in this image. The Deep Impact mission was supposed to end a few weeks later, but NASA approved an extension and renamed the spacecraft <a href="http://www.nasa.gov/mission_pages/epoxi/index.html" target="_blank" target="_blank">EPOXI</a> and sent it on to<a href="http://www.nasa.gov/mission_pages/epoxi/epoxi20101104b.html" target="_blank" target="_blank"> fly by Comet Hartley 2</a> in November 2010. The probe <a href="http://epoxi.umd.edu/" target="_blank" target="_blank">stopped communicating</a> with mission managers in September 2013 and was declared lost.

Deep Impact/EPOXI —

NASA's Deep Impact spacecraft was launched on January 12, 2005, and it traveled 268 million miles (431 million kilometers) to hurl its coffee table-sized probe into comet Tempel 1 on July 4, 2005. This image of Tempel 1 was taken by Deep Impact's camera 67 seconds after the probe hit the comet. Scattered light from the collision saturated the camera's detector and caused the bright splash seen in this image. The Deep Impact mission was supposed to end a few weeks later, but NASA approved an extension and renamed the spacecraft EPOXI and sent it on to fly by Comet Hartley 2 in November 2010. The probe stopped communicating with mission managers in September 2013 and was declared lost.

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Cassini —

The Cassini spacecraft ended its mission in 2017. The probe was launched on October 15, 1997, from Cape Canaveral Air Force Station in Florida. It arrived at Saturn on June 30, 2004. The spacecraft dropped a probe called Huygens to the surface of Saturn's moon Titan. It was the first landing on a moon in the outer solar system.

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Stardust —

The Stardust spacecraft was launched on February 7, 1999, from Cape Canaveral, Florida. After traveling 3.5 billion miles (5.6 billion kilometers), the spacecraft made history by capturing images of asteroid Annefrank and collecting samples of comet Wild 2 and successfully returning them to Earth. It also took spectacular images of comet Tempel 1. The probe's mission ended on March 25, 2011, when mission managers put it in safe mode and turned off the transmitter for the last time.

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Surveyor —

Surveyor 1 was the first U.S. spacecraft to make a soft landing on the Moon. The program ran during the mid-1960s and was declared a success. The program's focus eventually switched to support of the Apollo program.

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Explorer 1 —

A model of Explorer 1, America's first satellite, is held by, from left, NASA official William Pickering, scientist James Van Allen and rocket pioneer Wernher von Braun. The team was gathered at a news conference at the National Academy of Sciences in Washington to announce the satellite's successful launch. It had been launched a few hours before, on January 31, 1958.

NASA

CNN —

One of the Earth’s longest-flying spacecraft has detected a “persistent hum” beyond our solar system, according to a new study.

NASA’s Voyager 1 launched on September 5 1977, from Cape Canaveral, Florida, aboard a Titan-Centaur rocket, just weeks after its sister craft, Voyager 2. Although they were initially designed to last five years, more than 43 years after they launched, the crafts are still sending back data as they explore interstellar space.

Instruments aboard Voyager 1, which has moved past the edge of the solar system, through the solar system’s border with interstellar space, known as the heliopause, and into the interstellar medium, have detected the sounds of plasma waves, according to research published Monday in the journal Nature Astronomy.

A Cornell University-led team studied data transmitted from the spacecraft, sent from 14 billion miles away and discovered the interstellar gas emissions.

This artist's illustration depicts NASA's Voyager 1 spacecraft entering interstellar space.

NASA/JPL-Caltech

“It’s very faint and monotone, because it is in a narrow frequency bandwidth,” Stella Koch Ocker, a Cornell University doctoral student in astronomy, said in a statement. “We’re detecting the faint, persistent hum of interstellar gas.”

NASA’s Voyager 1 spacecraft flew by Jupiter in 1979, and by Saturn in 1980, before crossing the heliopause in August 2012.

After entering interstellar space, Voyager 1’s Plasma Wave System instrument detected oscillations in the gas, which is caused by our sun. But researchers also noticed that in between those eruptions, there was a steady and persistent signature.

Listen to the eerie sound here.

“The interstellar medium is like a quiet or gentle rain,” James Cordes, the George Feldstein Professor of Astronomy at Cornell and senior author of the study, said in a statement.

“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.”

Researchers think there is more low-level activity in the interstellar gas than was previously believed. This will allow researchers to monitor the spatial distribution of plasma. Voyager 1’s data can also help scientists understand the interactions between the interstellar medium and the sun’s solar wind, a steady stream of charged particles outflowing from our star.

“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,” Cornell research scientist Shami Chatterjee added.

“Regardless of what the sun is doing, Voyager is sending back detail,” Chatterjee said.

Voyager 1 is the most distant human-made object in space and continues to function, despite its age and distance.

“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.”

CNN’s Ashley Strickland contributed reporting.

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Voyager spacecraft detects ‘persistent hum’ beyond our solar system