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  • richardmitnick 3:35 pm on September 20, 2014 Permalink | Reply
    Tags: , , , , NASA Science News   

    From NASA: A Colorful Lunar Eclipse 

    NASA Science Science News

    Mark your calendar: On Oct. 8th, the Moon will pass through the shadow of Earth for a total lunar eclipse. Sky watchers in the USA will see the Moon turn a beautiful shade of celestial red and maybe turquoise, too. Watch, enjoy, learn.

    NASA leads the nation on a great journey of discovery, seeking new knowledge and understanding of our planet Earth, our Sun and solar system, and the universe out to its farthest reaches and back to its earliest moments of existence. NASA’s Science Mission Directorate (SMD) and the nation’s science community use space observatories to conduct scientific studies of the Earth from space to visit and return samples from other bodies in the solar system, and to peer out into our Galaxy and beyond. NASA’s science program seeks answers to profound questions that touch us all:

    This is NASA’s science vision: using the vantage point of space to achieve with the science community and our partners a deep scientific understanding of our planet, other planets and solar system bodies, the interplanetary environment, the Sun and its effects on the solar system, and the universe beyond. In so doing, we lay the intellectual foundation for the robotic and human expeditions of the future while meeting today’s needs for scientific information to address national concerns, such as climate change and space weather. At every step we share the journey of scientific exploration with the public and partner with others to substantially improve science, technology, engineering and mathematics (STEM) education nationwide.

    NASA

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  • richardmitnick 8:48 am on July 23, 2014 Permalink | Reply
    Tags: , , , , , NASA Science News   

    From NASA Science News: “Near Miss: The Solar Superstorm of July 2012″ 

    NASA Science Science News

    NASA Science News

    July 23, 2014
    Dr. Tony Phillips

    If an asteroid big enough to knock modern civilization back to the 18th century appeared out of deep space and buzzed the Earth-Moon system, the near-miss would be instant worldwide headline news.

    Two years ago, Earth experienced a close shave just as perilous, but most newspapers didn’t mention it. The “impactor” was an extreme solar storm, the most powerful in as much as 150+ years.

    “If it had hit, we would still be picking up the pieces,” says Daniel Baker of the University of Colorado.

    cme
    Coronal Mass Ejection

    Baker, along with colleagues from NASA and other universities, published a seminal study of the storm in the December 2013 issue of the journal Space Weather. Their paper, entitled A major solar eruptive event in July 2012, describes how a powerful coronal mass ejection (CME) tore through Earth orbit on July 23, 2012. Fortunately Earth wasn’t there. Instead, the storm cloud hit the STEREO-A spacecraft.

    stereo
    STEREO-A spacecraft

    “I have come away from our recent studies more convinced than ever that Earth and its inhabitants were incredibly fortunate that the 2012 eruption happened when it did,” says Baker. “If the eruption had occurred only one week earlier, Earth would have been in the line of fire.

    Extreme solar storms pose a threat to all forms of high-technology. They begin with an explosion–a “solar flare“—in the magnetic canopy of a sunspot. X-rays and extreme UV radiation reach Earth at light speed, ionizing the upper layers of our atmosphere; side-effects of this “solar EMP” include radio blackouts and GPS navigation errors. Minutes to hours later, the energetic particles arrive. Moving only slightly slower than light itself, electrons and protons accelerated by the blast can electrify satellites and damage their electronics. Then come the CMEs, billion-ton clouds of magnetized plasma that take a day or more to cross the Sun-Earth divide. Analysts believe that a direct hit by an extreme CME such as the one that missed Earth in July 2012 could cause widespread power blackouts, disabling everything that plugs into a wall socket. Most people wouldn’t even be able to flush their toilet because urban water supplies largely rely on electric pumps.

    Before July 2012, when researchers talked about extreme solar storms their touchstone was the iconic Carrington Event of Sept. 1859, named after English astronomer Richard Carrington who actually saw the instigating flare with his own eyes. In the days that followed his observation, a series of powerful CMEs hit Earth head-on with a potency not felt before or since. Intense geomagnetic storms ignited Northern Lights as far south as Cuba and caused global telegraph lines to spark, setting fire to some telegraph offices and thus disabling the ‘Victorian Internet.”

    A similar storm today could have a catastrophic effect. According to a study by the National Academy of Sciences, the total economic impact could exceed $2 trillion or 20 times greater than the costs of a Hurricane Katrina. Multi-ton transformers damaged by such a storm might take years to repair.

    “In my view the July 2012 storm was in all respects at least as strong as the 1859 Carrington event,” says Baker. “The only difference is, it missed.”

    In February 2014, physicist Pete Riley of Predictive Science Inc. published a paper in Space Weather entitled On the probability of occurrence of extreme space weather events. In it, he analyzed records of solar storms going back 50+ years. By extrapolating the frequency of ordinary storms to the extreme, he calculated the odds that a Carrington-class storm would hit Earth in the next ten years.

    The answer: 12%.

    “Initially, I was quite surprised that the odds were so high, but the statistics appear to be correct,” says Riley. “It is a sobering figure.”

    In his study, Riley looked carefully at a parameter called Dst, short for “disturbance – storm time.” This is a number calculated from magnetometer readings around the equator. Essentially, it measures how hard Earth’s magnetic field shakes when a CME hits. The more negative Dst becomes, the worse the storm. Ordinary geomagnetic storms, which produce Northern Lights around the Arctic Circle, but otherwise do no harm, register Dst=-50 nT (nanoTesla). The worst geomagnetic storm of the Space Age, which knocked out power across Quebec in March 1989, registered Dst=-600 nT. Modern estimates of Dst for the Carrington Event itself range from -800 nT to a staggering -1750 nT.

    In their Dec. 2013 paper, Baker et al. estimated Dst for the July 2012 storm. “If that CME had hit Earth, the resulting geomagnetic storm would have registered a Dst of -1200, comparable to the Carrington Event and twice as bad as the March 1989 Quebec blackout.”

    The reason researchers know so much about the July 2012 storm is because, out of all the spacecraft in the solar system it could have hit, it did hit a solar observatory. STEREO-A is almost ideally equipped to measure the parameters of such an event.

    “The rich data set obtained by STEREO far exceeded the relatively meagre observations that Carrington was able to make in the 19th century,” notes Riley. “Thanks to STEREO-A we know a lot of about the magnetic structure of the CME, the kind of shock waves and energetic particles it produced, and perhaps most importantly of all, the number of CMEs that preceded it.”

    It turns out that the active region responsible for producing the July 2012 storm didn’t launch just one CME into space, but many. Some of those CMEs “plowed the road” for the superstorm.

    A paper in the March 2014 edition of Nature Communications by UC Berkeley space physicist Janet G. Luhmann and former postdoc Ying D. Liu describes the process: The July 23rd CME was actually two CMEs separated by only 10 to 15 minutes. This double-CME traveled through a region of space that had been cleared out by yet another CME four days earlier. As a result, the storm clouds were not decelerated as much as usual by their transit through the interplanetary medium.

    “It’s likely that the Carrington event was also associated with multiple eruptions, and this may turn out to be a key requirement for extreme events,” notes Riley. “In fact, it seems that extreme events may require an ideal combination of a number of key features to produce the ‘perfect solar storm.'”

    “Pre-conditioning by multiple CMEs appears to be very important,” agrees Baker.

    A common question about this event is, how did the STEREO-A probe survive? After all, Carrington-class storms are supposed to be mortally dangerous to spacecraft and satellites. Yet STEREO-A not only rode out the storm, but also continued taking high-quality data throughout.

    “Spacecraft such as the STEREO twins and the Solar and Heliospheric Observatory (a joint ESA/NASA mission) were designed to operate in the environment outside the Earth’s magnetosphere, and that includes even quite intense, CME-related shocks,” says Joe Gurman, the STEREO project scientist at the Goddard Space Flight Center. “To my knowledge, nothing serious happened to the spacecraft.”

    The story might have been different, he says, if STEREO-A were orbiting Earth instead of traveling through interplanetary space.

    “Inside Earth’s magnetosphere, strong electric currents can be generated by a CME strike,” he explains. “Out in interplanetary space, however, the ambient magnetic field is much weaker and so those dangerous currents are missing.” In short, STEREO-A was in a good place to ride out the storm.

    “Without the kind of coverage afforded by the STEREO mission, we as a society might have been blissfully ignorant of this remarkable solar storm,” notes Baker. “How many others of this scale have just happened to miss Earth and our space detection systems? This is a pressing question that needs answers.”

    If Riley’s work holds true, there is a 12% chance we will learn a lot more about extreme solar storms in the next 10 years—when one actually strikes Earth.

    Says Baker, “we need to be prepared.”

    See the full article, with video, here.

    NASA leads the nation on a great journey of discovery, seeking new knowledge and understanding of our planet Earth, our Sun and solar system, and the universe out to its farthest reaches and back to its earliest moments of existence. NASA’s Science Mission Directorate (SMD) and the nation’s science community use space observatories to conduct scientific studies of the Earth from space to visit and return samples from other bodies in the solar system, and to peer out into our Galaxy and beyond. NASA’s science program seeks answers to profound questions that touch us all:

    This is NASA’s science vision: using the vantage point of space to achieve with the science community and our partners a deep scientific understanding of our planet, other planets and solar system bodies, the interplanetary environment, the Sun and its effects on the solar system, and the universe beyond. In so doing, we lay the intellectual foundation for the robotic and human expeditions of the future while meeting today’s needs for scientific information to address national concerns, such as climate change and space weather. At every step we share the journey of scientific exploration with the public and partner with others to substantially improve science, technology, engineering and mathematics (STEM) education nationwide.

    NASA


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  • richardmitnick 8:24 am on July 11, 2014 Permalink | Reply
    Tags: , , , NASA Science News   

    From NASA Science: “Three Supermoons in a Row “ 

    NASA Science Science News

    NASA Science News

    July 10, 2014
    Dr. Tony Phillips

    In June of last year, a full Moon made headlines. The news media called it a “supermoon” because it was 14% bigger and 30% brighter than other full Moons of 2013. Around the world, people went outside to marvel at its luminosity.

    If you thought one supermoon was bright, how about three….? The full Moons of summer 2014—July 12th, August 10th, and Sept. 9th–will all be supermoons.

    supermoon

    The scientific term for the phenomenon is “perigee moon.” Full Moons vary in size because of the oval shape of the Moon’s orbit. The Moon follows an elliptical path around Earth with one side (“perigee”) about 50,000 km closer than the other (“apogee”). Full Moons that occur on the perigee side of the Moon’s orbit seem extra big and bright.

    This coincidence happens three times in 2014. On July 12th and Sept 9th the Moon becomes full on the same day as perigee. On August 10th it becomes full during the same hour as perigee—arguably making it an extra-super Moon.”

    It might seem that such a sequence must be rare. Not so, says Geoff Chester of the US Naval Observatory.

    “Generally speaking, full Moons occur near perigee every 13 months and 18 days, so it’s not all that unusual,” he says. “In fact, just last year there were three perigee Moons in a row, but only one was widely reported.”

    In practice, it’s not always easy to tell the difference between a supermoon and an ordinary full Moon. A 30% difference in brightness can easily be masked by clouds and haze. Also, there are no rulers floating in the sky to measure lunar diameters. Hanging high overhead with no reference points to provide a sense of scale, one full Moon looks about the same size as any other.

    Chester expects most reports of giant Moons this summer to be … illusory.
    image

    1&2
    Perigee is the point in the Moon’s elliptical orbit closest to Earth. Diagrams:#1, #2

    “The ‘Moon Illusion’ is probably what will make people remember this coming set of Full Moons, more than the actual view of the Moon itself,” he says.

    The illusion occurs when the Moon is near the horizon. For reasons not fully understood by astronomers or psychologists, low-hanging Moons look unnaturally large when they beam through trees, buildings and other foreground objects. When the Moon illusion amplifies a perigee Moon, the swollen orb rising in the east at sunset can seem super indeed.

    “I guarantee that some folks will think it’s the biggest Moon they’ve ever seen if they catch it rising over a distant horizon, because the media will have told them to pay attention to this particular one,” says Chester.

    “There’s a part of me that wishes that this ‘super-Moon’ moniker would just dry up and blow away, like the ‘Blood-Moon’ that accompanied the most recent lunar eclipse, because it tends to promulgate a lot of mis-information,” admits Chester. “However, if it gets people out and looking at the night sky and maybe hooks them into astronomy, then it’s a good thing.”

    Indeed it is.

    See the full article here.

    NASA leads the nation on a great journey of discovery, seeking new knowledge and understanding of our planet Earth, our Sun and solar system, and the universe out to its farthest reaches and back to its earliest moments of existence. NASA’s Science Mission Directorate (SMD) and the nation’s science community use space observatories to conduct scientific studies of the Earth from space to visit and return samples from other bodies in the solar system, and to peer out into our Galaxy and beyond. NASA’s science program seeks answers to profound questions that touch us all:

    This is NASA’s science vision: using the vantage point of space to achieve with the science community and our partners a deep scientific understanding of our planet, other planets and solar system bodies, the interplanetary environment, the Sun and its effects on the solar system, and the universe beyond. In so doing, we lay the intellectual foundation for the robotic and human expeditions of the future while meeting today’s needs for scientific information to address national concerns, such as climate change and space weather. At every step we share the journey of scientific exploration with the public and partner with others to substantially improve science, technology, engineering and mathematics (STEM) education nationwide.

    NASA


    ScienceSprings is powered by MAINGEAR computers

     
  • richardmitnick 4:19 pm on November 25, 2013 Permalink | Reply
    Tags: , , , , NASA Science News   

    From NASA Science News: “Comet ISON vs. the Solar Storm” 

    NASA Science Science News

    Nov. 24, 2013

    Credits: Author: Dr. Tony Phillips | Production editor: Dr. Tony Phillips | Credit: Science@NASA

    In 2007, astronomers were amazed when a solar storm hit Comet Encke. NASA STEREO spacecraft watched as a CME (coronal mass ejection) struck the comet head on and ripped off its tail.

    The same thing could be in store for Comet ISON–only worse.

    ison
    ISON’s path

    dt
    ISON’s double tail

    On Nov. 28th, Comet ISON will pass through the sun’s atmosphere, flying little more than a million kilometers above the sun’s surface. It will be ~30 times closer to the sun than Encke was in 2007 and more likely to encounter a ferocious solar storm.

    “For one thing,” says Angelos Vourlidas of the Naval Research Lab and a participant in NASA’s Comet ISON Observing Campaign (CIOC), “the year 2007 was near solar minimum. Solar activity was low. Now, however, we are near the peak of the solar cycle and eruptions are more frequent.”

    “I would absolutely love to see Comet ISON get hit by a big CME,” says Karl Battams, an astronomer at the Naval Research Lab who also works with the CIOC. “It won’t hurt the comet, but it would give us a chance to study extreme interactions with the comet’s tail.”

    CMEs are magnetized clouds of plasma hurled into space by the explosions of sunspots. The gas inside a CME is not very dense, so its impact would not shatter a comet’s core. The fragile tail is another matter. Comet tails are as gossamer as the CMEs themselves, so the interactions can be intense and unpredictable.

    “The CME that ran over Comet Encke back in 2007 was slow, barely creating a pressure pulse by compressing the solar wind ahead of it,” notes Vourlidas. “It was this compression which caused the Encke’s tail to fly off.”

    He believes that Comet ISON would experience something more dramatic. “Any CME that hits Comet ISON close to the sun would very likely be faster, driving a shock wave with a much stronger magnetic field. Frankly, we can’t predict what would happen.”

    Comet ISON entered the field of view of STEREO-A’s Heliospheric Imager on Nov. 21st. Coincidentally, Comet Encke is there, too. Presently, the two comets are being gently buffeted by solar wind and their tails are wagging back and forth accordingly.

    If the sun erupts, both comets could be engulfed by the same CME. This would turn the two comets into solar probes. Like wind socks, they would sample the storm from two widely separated locations, giving researchers a rare 3D view of a CME’s inner structure.

    Comet ISON will be passing over the sun’s equator on Nov. 28th on the same side of the sun where a group of active sunspots was recently clustered. In other words, says Battams, “we’re going to be in the ‘hot zone’ for CMEs.”

    NASA’s entire fleet of solar observatories will be watching when ISON takes the plunge. This includes STEREO-A and STEREO-B, the Solar Dynamics Observatory, and the Solar and Heliophysics Observatory (SOHO), which NASA operates along with the European Space Agency. If a CME strikes the comet, all of the spacecraft are likely to see what happens.

    “It would be pretty new territory for us,” says Battams.

    “…and a nice preview of what NASA’s Solar Probe+ spacecraft might experience when it plunges into the sun in the 2020s,” adds Vourlidas.

    Stay tuned!

    See the full article, with videos, here.

    NASA leads the nation on a great journey of discovery, seeking new knowledge and understanding of our planet Earth, our Sun and solar system, and the universe out to its farthest reaches and back to its earliest moments of existence. NASA’s Science Mission Directorate (SMD) and the nation’s science community use space observatories to conduct scientific studies of the Earth from space to visit and return samples from other bodies in the solar system, and to peer out into our Galaxy and beyond. NASA’s science program seeks answers to profound questions that touch us all:

    This is NASA’s science vision: using the vantage point of space to achieve with the science community and our partners a deep scientific understanding of our planet, other planets and solar system bodies, the interplanetary environment, the Sun and its effects on the solar system, and the universe beyond. In so doing, we lay the intellectual foundation for the robotic and human expeditions of the future while meeting today’s needs for scientific information to address national concerns, such as climate change and space weather. At every step we share the journey of scientific exploration with the public and partner with others to substantially improve science, technology, engineering and mathematics (STEM) education nationwide.

    NASA


    ScienceSprings is powered by MAINGEAR computers

     
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