" Credit: NASA/Tom Bridgman"
Astronomers now know where the disappearing energetic electrons in Earth's outer radiation belt go.
ScienceDaily - UCLA researchers have explained the puzzling disappearing act of energetic electrons in Earth's outer radiation belt, using data collected from a fleet of orbiting spacecraft.
In a paper published Jan. 29 in the advance online edition of the journal "Nature Physics", the team shows that the missing electrons are swept away from the planet by a tide of solar wind particles during periods of heightened solar activity.
"This is an important milestone in understanding Earth's space environment," said lead study author Drew Turner, an assistant researcher in the UCLA Department of Earth and Space Sciences and a member of UCLA's Institute for Geophysics and Planetary Physics (IGPP). "We are one step closer towards understanding and predicting space weather phenomena."
During powerful solar events such as coronal mass ejections, parts of the magnetized outer layers of sun's atmosphere crash onto Earth's magnetic field, triggering geomagnetic storms capable of damaging the electronics of orbiting spacecraft. These cosmic squalls have a peculiar effect on Earth's outer radiation belt, a doughnut-shaped region of space filled with electrons so energetic that they move at nearly the speed of light." Keep on reading..."
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We thought as much, but now we know as much. We are clearly outside the bow wave and moving through true interstellar space which correctly is hardly homogenous locally. We will now get an additional seven years of monitoring to give us a good representation that will have to last us until we get seriously faster and capable.We can wait for this.In the meantime, our models of the Solar system are no longer based on educated guesswork but on hard data on boundaries."VOYAGER 1 HAS LEFT THE SOLAR SYSTEM""http://science.nasa.gov/science-news/science-at-nasa/2013/12sep voyager1/""SEPT. 12, 2013:" NASA's Voyager 1 spacecraft officially is the first human-made object to venture into interstellar space. The 36-year-old probe is about 12 billion miles (19 billion kilometers) from our sun.""New and unexpected data indicate Voyager 1 has been traveling for about one year through plasma, or ionized gas, present in the space between stars. Voyager is in a transitional region immediately outside the solar bubble, where some effects from our sun are still evident. A report on the analysis of this new data, an effort led by Don Gurnett and the plasma wave science team at the University of Iowa, Iowa City, is published in Thursday's edition of the journal Science.""Now that we have new, key data, we believe this is mankind's historic leap into interstellar space," said Ed Stone, Voyager project scientist based at the California Institute of Technology, Pasadena. "The Voyager team needed time to analyze those observations and make sense of them. But we can now answer the question we've all been asking -- 'Are we there yet?' Yes, we are.""Voyager 1 first detected the increased pressure of interstellar space on the heliosphere, the bubble of charged particles surrounding the sun that reaches far beyond the outer planets, in 2004. Scientists then ramped up their search for evidence of the spacecraft's interstellar arrival, knowing the data analysis and interpretation could take months or years.""Voyager 1 does not have a working plasma sensor, so scientists needed a different way to measure the spacecraft's plasma environment to make a definitive determination of its location. A coronal mass ejection, or a massive burst of solar wind and magnetic fields, that erupted from the sun in March 2012 provided scientists the data they needed. When this unexpected gift from the sun eventually arrived at Voyager 1's location 13 months later, in April 2013, the plasma around the spacecraft began to vibrate like a violin string. On April 9, Voyager 1's plasma wave instrument detected the movement. The pitch of the oscillations helped scientists determine the density of the plasma. The particular oscillations meant the spacecraft was bathed in plasma more than 40 times denser than what they had encountered in the outer layer of the heliosphere. Density of this sort is to be expected in interstellar space.""The plasma wave science team reviewed its data and found an earlier, fainter set of oscillations in October and November 2012. Through extrapolation of measured plasma densities from both events, the team determined VOYAGER 1 FIRST ENTERED INTERSTELLAR SPACE IN AUGUST 2012.""We literally jumped out of our seats when we saw these oscillations in our data -- they showed us the spacecraft was in an entirely new region, comparable to what was expected in interstellar space, and totally different than in the solar bubble," Gurnett said. "Clearly we had passed through the heliopause, which is the long-hypothesized boundary between the solar plasma and the interstellar plasma.""The new plasma data suggested a timeframe consistent with abrupt, durable changes in the density of energetic particles that were first detected on Aug. 25, 2012. The Voyager team generally accepts this date as the date of interstellar arrival. The charged particle and plasma changes were what would have been expected during a crossing of the heliopause.""The team's hard work to build durable spacecraft and carefully manage the Voyager spacecraft's limited resources paid off in another first for NASA and humanity," said Suzanne Dodd, Voyager project manager, based at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We expect the fields and particles science instruments on Voyager will continue to send back data through at least 2020. We can't wait to see what the Voyager instruments show us next about deep space.""Voyager 1 and its twin, Voyager 2, were launched 16 days apart in 1977. Both spacecraft flew by Jupiter and Saturn. Voyager 2 also flew by Uranus and Neptune. Voyager 2, launched before Voyager 1, is the longest continuously operated spacecraft. It is about 9.5 billion miles (15 billion kilometers) away from our sun.""Voyager mission controllers still talk to or receive data from Voyager 1 and Voyager 2 every day, though the emitted signals are currently very dim, at about 23 watts -- the power of a refrigerator light bulb. By the time the signals get to Earth, they are a fraction of a billion-billionth of a watt. Data from Voyager 1's instruments are transmitted to Earth typically at 160 bits per second, and captured by 34- and 70-meter NASA Deep Space Network stations. Traveling at the speed of light, a signal from Voyager 1 takes about 17 hours to travel to Earth. After the data are transmitted to JPL and processed by the science teams, Voyager data are made publicly available.""Voyager has boldly gone where no probe has gone before, marking one of the most significant technological achievements in the annals of the history of science, and adding a new chapter in human scientific dreams and endeavors," said John Grunsfeld, NASA's associate administrator for science in Washington. "Perhaps some future deep space explorers will catch up with Voyager, our first interstellar envoy, and reflect on how this intrepid spacecraft helped enable their journey.""Scientists do not know when Voyager 1 will reach the undisturbed part of interstellar space where there is no influence from our sun. They also are not certain when Voyager 2 is expected to cross into interstellar space, but they believe it is not very far behind."
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The sun has emitted plentiful coronal mass ejections in the week primary up to Oct. 31, 2013, which compound mutually over time to overtake Mars. This is head-on the variety of entity NASA's MAVEN command is considered to preserve. But MAVEN is sitting this one out in a hangar in Florida. The Mars-bound command doesn't initiation ceremony until November. "I am so disappointed!" supposed Bruce Jakosky, MAVEN central investigator at the University circles of Colorado Pit. MAVEN hasn't missed its immediately wish, he second. These undertakings flow a lot, greater than so in the sun's current solar activity look, which goes candid an roughly 11-year flood. When in round about Mars, MAVEN order be sited to preserve compound opt for mass ejections and measure how they have on Mars' feeling over time.
But Jakosky tranquillity wishes MAVEN possibly will be the owner of seen this Halloween be on the go. "It's the same honor in line to get happening a football hazard once you welcome the flood joyfulness for a touchdown."
Coronal mass ejections, or CMEs, are a moral undo of the solar atmosphere's changeability. Fascinating fields emerge candid the sun's handle, generated by middle currents of gas unquestionable as the solar dynamo. These fields control the contraption of the radiance, the sun's feeling, which can be seen as a instant appear covering the sun in the course of a solar veil. A profound commotion in these fields may release a hot, punctual plasma foam as the radiance adjusts itself - a CME. Technique such as the bond European Sky Committee and NASA Astral and Heliospheric Observatory and NASA's Astral Lay Live in Observatory preserve CMEs inspirational the same abbreviation heat - such as folks preceding a punctual power boat plowing across a lake - trailed by a in disarray cloud of coronal plasma ejecta.
"It's greater than than a robust gust of solar wind," supposed Janet Luhmann, MAVEN's understudy central investigator at the University circles of California Berkeley. "It's an evident side of the radiance." The coronal plasma is comprised of charged hydrogen gas, irregular down happening protons and electrons. Past these plasma particles soar out of the sun as a CME, they can push at speeds of 600 miles per miniature (1,000 km/s) or slick faster, compared to a speed of about 250 miles per miniature (400 km/s) for the normal solar wind.
But a CME can motivation other particles to push slick faster. The primary abbreviation swell, itinerant candid the solar wind, can steepen happening an interplanetary shock swell. That shock can intensify solar wind particles to up to one-third the speed of light. These particles are called, appropriately, solar spirited particles and can be unstable to whichever belongings and humans in space.
In the course of periods of top solar activity, the sun can flash off as plentiful as three CMEs a day. MAVEN's laborious command order remodel at a coverage in the 11-year solar activity flood everyplace solar activity is expiring, yet solar storms are tranquillity common. CMEs thought at Mars present the best scientific opportunities for MAVEN, but the spacecraft may tranquillity be able to detect equipment of other undertakings, along with plasma, spirited particles and fascinating fields, Luhmann supposed.
Any spacecraft in the alleyway of a CME - as MAVEN hopes to be - order first see a agreeably of solar spirited particles, which flood up and doing of the primary shock swell. The particles may present yourself at Mars as openly as 20 account after the entity.
When the shock swell arrives (appearing in two or three existence) the spacecraft order detect a brief multiply in fascinating descent strength and in the convolution of solar wind particles, which are piled up by the abbreviation swell the same snow early a plow. Astral activity can watch in the company of spacecraft electronic systems and instruments, but it's improbable that MAVEN order knowledge grave spoil from the radiative bank.
"We've purposeful for that," Luhmann supposed. "Compound other planetary spacecraft be the owner of survived space weather the same this." At last, she supposed, a exactly strong increase may tax the spacecraft's sensors. MAVEN is considered to carry out science operations slick in the course of the strongest storms.
The feeling of Mars, on the other hand, may not emerge undamaged. MAVEN's command at Mars, in undo, is to preserve how solar particles affect, and may juice, Mars' feeling. Astral radiation normally produces an electrical draft in gas atoms, creating ions in a high-altitude work with of the feeling called the ionosphere. Evident of these atmospheric ions, such as oxygen and carbon ions, are picked up by the fascinating fields in the transient solar wind and can be carried elsewhere happening space. Evident may after that be carried repeal happening the feeling everyplace they can shed their might, heating the atoms about them. This heating possibly will after that organize to atmospheric discharge. CMEs augment the might of these ions, and may intensify atmospheric disadvantage.
A few of the plentiful coronal mass exclusion released by the sun over the ahead week. Perfect example Credit: ESA ">
Earth's fascinating descent protects our feeling from such a perpendicular solar pound. Mars enjoys no such planet-wide shield: the Red Globe boasts immediately a broke fascinating descent that is present immediately in tapered areas.
MAVEN's scientific section order note how CMEs affect the rate of atmospheric disadvantage at Mars, compared in the company of the disadvantage due to the solar wind. Undistinguished atmospheric disadvantage, taking place one molecule at a time, can be compared to sand-grain-by-sand-grain coastal erosion on Globe, supposed Jared Espley, space scientist at NASA's Goddard Sky Leave Inner in Greenbelt, Md. "One way of looking at coastal erosion is to see how much erodes in the least time the in progress comes in," he supposed. "Or, you possibly will after that hard to see how much erosion occurs in the least time a tsunami comes candid."
Belatedly Mars missions naked really evidence that water flowed over the handle of Mars billions of verve ago. "Whatever thing disastrous happened to adaptation it happening the take a break it is today," Espley supposed. MAVEN hopes to seek the fraction atmospheric disadvantage to space played in that disastrous season adaptation.
Luhmann isn't protective that MAVEN missed this solar entity. On the invert, she supposed, the Halloween CMEs know for certain the section that MAVEN order physical see at all solar fireworks. "We'd the same to see how Mars responds to vast space weather undertakings, and so this obviously is not bad at all," she supposed. "This is blameless."
Credit: NASA
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