Study Captures Science Data from Great American Eclipse

Study Captures Science Data from Great American Eclipse:

Two NASA WB-57F research aircraft successfully tracked the August 21 solar eclipse as part of a NASA project led by Southwest Research Institute (SwRI) to study the solar corona and Mercury’s surface. “The visible and infrared data look spectacular,” said SwRI senior research scientist Dr. Amir Caspi, principal investigator of the project. “We’re already seeing some surprising features, and we are very excited to learn what the detailed analysis will reveal.”

The team began initial analysis of the data gathered during the flights, showing clear images of the Sun’s outer atmosphere and thermal images of Mercury’s surface. Initial results are expected to be released in a few months and presented at the fall meeting of the American Geophysical Union in December 2017.

Total solar eclipses are unique opportunities for scientists to study the hot atmosphere above the Sun’s visible surface. The faint light from the corona is usually overpowered by intense emissions from the Sun itself. During a total eclipse, however, the Moon blocks the glare from the bright solar disk and darkens the sky, allowing weaker coronal emissions to be observed.

“This is the best observed eclipse ever,” said Dr. Dan Seaton, co-investigator of the project from the University of Colorado. “With the results from the WB-57s and complementary observations from space and other experiments on the ground, we have an opportunity to answer some of the most fundamental questions about the nature of the corona.”

The eclipse also provided an opportunity for scientists to study Mercury, which is notoriously difficult to image because of its proximity to the Sun. “The infrared images of Mercury were much brighter than we originally expected,” said Caspi. Using infrared observations in near darkness through very little atmosphere, the team received data enabling it, for the first time, to attempt to estimate the surface temperature distribution over the planet’s night side. “It will be incredibly interesting to dig into these data,” said Dr. Constantine Tsang, SwRI senior research scientist and a co-investigator on the project.

The team used stabilized telescopes with sensitive, high-speed, visible-light and infrared cameras aboard the research aircraft from an altitude of 50,000 feet, providing a significant advantage over ground-based observations. These are the first astronomical observations for the Houston-based WB-57Fs. Southern Research, of Birmingham, Ala., built the Airborne Imaging and Recording Systems (AIRS) and worked with the scientific team to upgrade its DyNAMITE telescopes onboard the planes with solar filters and improved data recorders and operating software.

“The pilots, instrument operators, and engineers did a phenomenal job getting us exactly the data we asked for,” said Caspi. “Achieving this quality of measurement required an enormous effort and precise timing, and everyone hit their mark exactly. I am honored to be part of such an exceptionally talented and professional team, and grateful for everyone’s dedication and hard work.”

The SwRI-led team includes scientists from the University of Colorado, the National Center for Atmospheric Research High Altitude Observatory, and the Smithsonian Astrophysical Observatory, as well as international colleagues at Trinity College Dublin in Ireland and the Royal Observatory of Belgium.

Credit: swri.org

Phoenicid Meteor Shower from Dead Comet Arises Again After 58 Years

Phoenicid Meteor Shower from Dead Comet Arises Again After 58 Years:

The Phoenicid meteor shower (named after the constellation Phoenix) was discovered by the first Japanese Antarctic Research Expedition on December 5, 1956, during their voyage in the Indian Ocean. However, it has not been observed again. This has left astronomers with a mystery: where did the Phoenicids come from and where did they go?

Two Japanese teams have found an answer to these questions by linking the Phoenicid meteor shower to a vanished celestial body, Comet Blanpain. This comet appeared in 1819 for the first time and then disappeared. In 2003 astronomers discovered a minor body moving along the same orbit as Comet Blanpain had over 100 years ago and showed that it was the remains of Comet Blanpain. The iconic coma and tail of a comet are made of gas and dust which escaped from the surface of the nucleus. The reason why Comet Blanpain reappeared as an asteroid was probably because all the gas and dust have escaped from this central body. Now rather than calling the object a "comet" it might be more accurate to refer to it as an "asteroid."

Although all of the gas and dust have escaped from Comet Blanpain into space, they now form a dust trail which revolves along almost the same orbit as Comet Blanpain itself, and gradually spread along the orbit. When such a dust trail encounters the Earth, the dust particles impinge into the atmosphere and ablate, which are observed as meteors.

Assuming that Comet Blanpain is the parent body of the Phoenicids, the teams performed calculations and predicted that the Phoenicids should be observed again on December 1, 2014. Following this prediction, the two teams of Japanese astronomers carried out a campaign of observation. One team led by Yasunori Fujiwara, a graduate student at the Department of Polar Science, SOKENDAI (The Graduate University for Advanced Studies), and Takuji Nakamura, a professor of the National Institute of Polar Research/SOKENDAI, traveled to North Carolina, U.S.A., and observed there. The other team led by Mikiya Sato, an astronomical officer at Kawasaki Municipal Science Museum, and Junichi Watanabe, a professor of the National Astronomical Observatory of Japan/SOKENDAI, visited La Palma Island in the Spanish territory off the West coast of Africa for observations. The weather condition at the former site was comparatively good, but more clouds covered at the latter site. Therefore, Sato's team supplementary used data from other sources such as NASA's All Sky Fireball Network and radar observations at the University of Western Ontario, Canada.

Just because meteors appeared, doesn't mean they are part of the Phoenicid meteor shower; Earth is bombarded by a constant background of sporadic meteors every night. In order to distinguish Phoenicids from sporadic meteors, both teams analyzed the data, by back-tracing each meteor trail to distinguish the meteor shower. If many meteors come from the same point in the sky, then they are part of the same meteor shower. Out of the 138 meteors observed at North Carolina, 29 were identified as Phoenicids. The Phoenicid activity peaked between 8 pm to 9 pm local time, very close to the predicted peak of the Phoenicid meteor shower, which was 7 pm to 8 pm. This fact has further supported that the observed meteors back-traced to the Phoenicid radiant are surely from Phoenicid meteor shower. The data collected by the other sources also supported this result.

But not everything matched the predictions. One discrepancy between the prediction and the observations was that the number of Phoenicids observed was only 10% of the prediction. This indicates that Comet Blanpain was active, but only to a limited extent when the observed meteors were released from the comet when it approached the Sun in the early 20th Century. To summarize, the observed meteor shower is the first example for the astronomers where the evolution of a comet has been estimated. Fujiwara enthusiastically states, "we would like to apply this technique to many other meteor showers for which the parent bodies are currently without clear cometary activities, in order to investigate the evolution of minor bodies in the Solar System."

Fujiwara's research is being published in the "Publications of the Astronomical Society of Japan," and Sato's research will appear in the journal "Planetary and Space Science" very soon.

Credit: soken.ac.jp

Bold Space Travel

Bold Space Travel:

Transforming science fiction to reality, physics professor Philip Lubin is creating a laser-cannon system to propel miniature spaceships with solar sails more than 25 trillion miles to the sun’s nearest star — Proxima Centuari. Loaded with cameras, other sensors, historical records of humanity, greetings from Earth and possibly human DNA, the smartphone-sized crafts, or interstellar arks, would be thrust on an historic journey that would take about 20 years — a blink of an eye in space travel.

“People understood roughly 100 years ago that it was possible using then-technology to send a human to the moon and return them,” Lubin said, noting that one challenge was scaling down equipment. “If you look at the popular literature at that time, the idea was treated as science fiction, like Flash Gordon.”

Lubin’s ambitious vision is showcased in “Laser-Sailing Starships,” one of eight volumes in the new series “Out of this World” published by World Book (of encyclopedia fame). Targeted to middle-school students, the books focus on research fellows involved in the NASA Innovative Advanced Concepts program. NASA aims to foster the next generation of scientific talent.

“The great part about the whole series is that it doesn’t talk down to kids, but addresses the science head-on,” said Jason Derleth, the program executive for NASA, which helps fund Lubin’s research.

In 2009, Lubin began examining how to use directed energy — a phased laser array — to deflect asteroids bound for Earth. But there was limited outside interest in the UCSB research, he said, because the planet doesn’t get hit often. 

That changed dramatically in 2013. Lubin and his team had been focused on the expected near-Earth flyby of the DA14 asteroid (about 17,000 miles away). However, only hours before the asteroid was scheduled to pass the planet, Russia was struck by the Chelyabinsk meteor with the force of strategic nuclear bomb. The event directed worldwide media attention on Lubin and his team of student researchers in the Department of Physics.

“I woke up the next day and someone called to tell me Russia got hit with a meteor — I thought they were joking,” Lubin said. “At that point, things kind of went nuts. That singular event was completely coincidental — there was no relationship between the two cosmic events.”

Amid the recognition, Lubin’s concept presented in earlier research — using his asteroid-deflection technology to provide relativistic-speed propulsion for an interstellar mission — captured the attention of NASA and the United States Congress. In separate meetings with the space agency and legislators, Lubin described launching hundreds of the tiny crafts in the hope one or more reaches Proxima Centuari — a red dwarf about one-eighth the sun’s size. 

“A large number of scientists have looked at the technical paper we wrote in 2015 on how to accomplish this,” Lubin said. “Except for saying this is going to be hard to do, no one has found a fatal flaw.”

Credit: ucsb.edu

The Puzzle of Ultra-Diffuse Galaxies

The Puzzle of Ultra-Diffuse Galaxies:

Our solar system is located in a spiral galaxy composed of billions of stars, the Milky Way. With the naked eye, we can see some 3000 stars in a dark night. However, if Earth would reside within an ultra-diffuse galaxy, we would only spot a few dozen stars on the sky. Galaxies of this type were either not able to produce more stars in the first place, or they got stripped of their stars by tidal forces.

Intriguingly, though, larger telescopes and improved imaging techniques have recently led to the discovery of many ultra-diffuse galaxies in the harshest environments possible: galaxy clusters.

"We have been asking ourselves how these fragile objects are able to survive among such dense, massive accumulations of hundreds of large and small galaxies", explains Carolin Wittmann, PhD student at the Astronomisches Rechen-Institut (ARI) of the Zentrum für Astronomie der Universität Heidelberg (ZAH). Using very deep optical images obtained in 2012 with the Prime Focus Camera (PFIP) of the William Herschel Telescope (WHT), Ms Wittmann identified about 90 such galaxies in the core of the Perseus Cluster, 240 million light-years away. 

Astronomers wonder how these vulnerable galaxies are able to survive among such dense, massive accumulations of hundreds of large and small galaxies. Are they possibly protected by a high dark matter content? Or might they be just now in the process of tidal disruption?

"Surprisingly, most galaxies appear intact — only very few show signs of ongoing disruption," emphasizes Dr Thorsten Lisker, who initiated the project. If this means that the ultra-diffuse galaxies can withstand the strong tidal field of the Perseus Cluster, then they must contain a large amount of unseen mass—dark matter—whose gravitational attraction acts as a binding force. 

Tidal forces may, however, be the reason why galaxies with the largest sizes are not found in the Perseus cluster core, while being present in the outer regions of other galaxy clusters. Along with international partners, the researchers are now hoping to obtain data of similar quality on the outskirts of the Perseus Cluster, where the environmental influence would have been less strong, preserving more of the original structure of the galaxies.

Credit: ing.iac.es

Kepler Spacecraft Discovers Variability in the Seven Sisters

Kepler Spacecraft Discovers Variability in the Seven Sisters:

The Seven Sisters, as they were known to the ancient Greeks, are now known to modern astronomers as the Pleiades star cluster – a set of stars which are visible to the naked eye and have been studied for thousands of years by cultures all over the world. Now Dr Tim White of the Stellar Astrophysics Centre at Aarhus University and his team of Danish and international astronomers have demonstrated a powerful new technique for observing stars such as these, which are ordinarily far too bright to look at with high performance telescopes. Their work is published in the Monthly Notices of the Royal Astronomical Society.

Using a new algorithm to enhance observations from the Kepler Space Telescope in its K2 Mission, the team has performed the most detailed study yet of the variability of these stars. Satellites such as Kepler are engineered to search for planets orbiting distant stars by looking for the dip in brightness as the planets pass in front, and also to do asteroseismology, studying the structure and evolution of stars as revealed by changes in their brightness.

Because the Kepler mission was designed to look at thousands of faint stars at a time, some of the brightest stars are actually too bright to observe. Aiming a beam of light from a bright star at a point on a camera detector will cause the central pixels of the star's image to be saturated, which causes a very significant loss of precision in the measurement of the total brightness of the star. This is the same process which causes a loss of dynamic range on ordinary digital cameras, which cannot see faint and bright detail in the same exposure.

"The solution to observing bright stars with Kepler turned out to be rather simple," said lead author Dr Tim White. "We're chiefly concerned about relative, rather than absolute, changes in brightness. We can just measure these changes from nearby unsaturated pixels, and ignore the saturated areas altogether."

But changes in the satellite's motion and slight imperfections in the detector can still hide the signal of stellar variability. To overcome this, the authors developed a new technique to weight the contribution of each pixel to find the right balance where instrumental effects are cancelled out, revealing the true stellar variability. This new method has been named halo photometry, a simple and fast algorithm the authors have released as free open-source software.

Most of the seven stars are revealed to be slowly-pulsating B stars, a class of variable star in which the star's brightness changes with day-long periods. The frequencies of these pulsations are key to exploring some of the poorly understood processes in the core of these stars.

The seventh star, Maia, is different: it varies with a regular period of 10 days. Previous studies have shown that Maia belongs to a class of stars with abnormal surface concentrations of some chemical elements such as manganese. To see if these things were related, a series of spectroscopic observations were taken with the Hertzsprung SONG Telescope.

"What we saw was that the brightness changes seen by Kepler go hand-in-hand with changes in the strength of manganese absorption in Maia's atmosphere," said Dr Victoria Antoci, a co-author of the work and Assistant Professor at the Stellar Astrophysics Centre, Aarhus University. "We conclude that the variations are caused by a large chemical spot on the surface of the star, which comes in and out of view as the star rotates with a ten day period."

"Sixty years ago, astronomers had thought they could see variability in Maia with periods of a few hours and suggested this was the first of a whole new class of variable stars they called 'Maia Variables'," White said, "but our new observations show that Maia is not itself a Maia Variable!"

No signs of exoplanetary transits were detected in this study, but the authors show that their new algorithm can attain the precision that will be needed for Kepler and future space telescopes such as the Transiting Exoplanet Survey Satellite (TESS) to detect planets transiting stars as bright as our neighboring star Alpha Centauri. These nearby bright stars are the best targets for future missions and facilities such as the James Webb Space Telescope, which is due to launch in late 2018.

Credit: ras.org.uk

The Crown of the Sun

The Crown of the Sun:

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2017 August 23

Explanation: During a total solar eclipse, the Sun's extensive outer atmosphere, or corona, is an inspirational sight. Streamers and shimmering features visible to the eye span a brightness range of over 10,000 to 1, making them notoriously difficult to capture in a single photograph. But this composite of telescopic images covers a wide range of exposure times to reveal the crown of the Sun in all its glory. The aligned and stacked digital frames were taken in clear skies above Stanley, Idaho in the Sawtooth Mountains during the Sun's total eclipse on August 21. A pinkish solar prominence extends just beyond the right edge of the solar disk. Even small details on the dark night side of the New Moon can be made out, illuminated by sunlight reflected from a Full Earth.

The Eagle and The Swan

The Eagle and The Swan:

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2017 August 24


The Eagle and The Swan

Image Credit & Copyright: Josep Drudis


Explanation: The Eagle Nebula and the Swan Nebula span this broad starscape, a telescopic view toward the Sagittarius spiral arm and the center of our Milky Way galaxy. The Eagle, also known as M16, is at top and M17, the Swan, at bottom of the frame showing the cosmic clouds as brighter regions of active star-formation. They lie along the spiral arm suffused with reddish emission charactistic of atomic hydrogen gas, and dusty dark nebulae. M17, also called the Omega Nebula, is about 5500 light-years away, while M16 is some 6500 light-years distant. The center of both nebulae are locations of well-known close-up images of star formation from the Hubble Space Telescope. In this mosaic image that extends about 3 degrees across the sky, narrowband, high-resultion image data has been used to enhance the central regions of the Eagle and Swan. The extended wings of the Eagle Nebula spread almost 120 light-years. The Swan is over 30 light-years across.

Tomorrow's picture: pixels in space

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Diamond Ring in a Cloudy Sky

Diamond Ring in a Cloudy Sky:

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2017 August 25

Explanation: As the Moon's shadow swept across the US on August 21, eclipse chasers in the narrow path of totality were treated to a diamond ring in the sky. At the beginning and end of totality, the fleeting and beautiful effect often produces audible gasps from an amazed audience. It occurs just before or after the appearance of the faint solar corona with a brief ring of light and glimpse of Sun. In this scene from the end of totality at Central, South Carolina, clouds drift near the Sun's diamond ring in the sky.

Saturn-lit Tethys

Saturn-lit Tethys: Cassini gazes across the icy rings of Saturn toward the icy moon Tethys, whose night side is illuminated by Saturnshine, or sunlight reflected by the planet.

Original enclosures:

The Eclipse 2017 Umbra Viewed from Space

The Eclipse 2017 Umbra Viewed from Space: As millions of people across the United States experienced a total eclipse as the umbra, or moon’s shadow passed over them, only six people witnessed the umbra from space. The space station crossed the path of the eclipse three times as it orbited above the continental United States at an altitude of 250 miles.

Original enclosures:

Incredible Solar Eclipse Images From Our Readers

Incredible Solar Eclipse Images From Our Readers:



Holy moly, that was awesome! Incredible, fantastic, amazing…there just aren’t the words to describe what it is like to experience totality. While I’m trying to come down to Earth and figure out how to explain how wonderful this was, enjoy the beautiful images captured by our readers from across the US and those from across the world who traveled to capture one of nature’s most spectacular events: a total solar eclipse.

The images from those seeing partial eclipses are wonderful, as well, and we’ll keep adding them as they come in (update, we just got some from Europe too). Great job everyone!

Eclipse panorama. Got some cool Baily’s Beads and that prominence is nuts! Shot at 2000mm on an old Celestron 8in telescope! Credit and copyright: Kenneth Brandon.

2017 Solar Eclipse from Clayton GA, USA.
Celestron C8 Telescope on CGEM. Canon T3i (Modified IR enhanced), Solar Filter. Credit and copyright: Michael Bee.

The August 21, 2017 total solar eclipse over the Grand Tetons as seen from the Teton Valley in Idaho, near Driggs. ..This is from a 700-frame time-lapse and is of second contact just as the diamond ring is ending and the dark shadow of the Moon is approaching from the west at right, darkening the sky at right, and beginning to touch the Sun. The peaks of the Tetons are not yet in the umbral shadow and are still lit by the partially eclipsed Sun. ..With the Canon 6D and 14mm SP Rokinon lens at f/2.5 for 1/10 second at ISO 100. Credit and copyright: Alan Dyer.

Total Solar Eclipse, August 21, 2017 as seen from Tellico Plains, Tennessee. New City Expedition, photo by Igor Kuskovsky.

Total Solar Eclipse, Aug. 21, 2017, as seen from Charleston, South Carolina. Credit and copyright: Jason Major

Partial Eclipse montage from Charlottesville, Virginia. Credit and copyright: David Murr.

Partial Solar Eclipse August 21st 2017, as seen from Fullerton California USA. Sky: Partially Cloudy. Telescope: Nexstar 102 SLT Refractor, Camera: Fujifilm X-T1 @ Prime Focus. Credit and copyright: Jimmy CD.

From the total solar eclipse as seen in Columbia, Missouri, on Aug. 21, 2017. Credit and copyright: Wildhaven Creative.

Total Eclipse from Shaw Air Force Base (August 21, 2017). It was magical. Credit and copyright: Michael Seeley.

#Eclipse 2017 From Laval. Aug 21 2017. @CosmodomeLaval #meteoqc @universetoday pic.twitter.com/HFAeH695dD

— FelipeSg (@SanFelipeSG) August 21, 2017

#Timelapse of totality over Salem, #Oregon. So cool! #eclipse2017 @universetoday @JimCantore @ericfisher @StephanieAbrams @ZachsORoutdoors pic.twitter.com/TzV4Vil2xq

— Mike Cohea (@MikeCohea) August 21, 2017

Short video I took from McMinnville, TN. Can you see it!!! ?? #Eclipse2017 pic.twitter.com/zVNXvLOLSI

— Holly ? (@absolutspacegrl) August 21, 2017

That moment of #SolarEclipse2017 pic.twitter.com/8u8Xz79aWi

— Zaid Benjamin (@zaidbenjamin) August 21, 2017

Partial solar eclipse, seen from the west coast of France, August 21, 2017. Credit and copyright: Frank Tyrlik.

Aerial panorama of the total solar eclipse over Kansas. Two minutes earlier it was still raining. #eclipse #eclipse2017 @DJIGlobal pic.twitter.com/1zSIsKlZ8E

— Romeo Durscher (@romeoch) August 21, 2017

Great American Eclipse, 21-08-2017. Silver Falls Oregon 10:17-10:19 local time. Raw straight out of the camera. 65mm Refractor / Canon 700D. Credit and copyright: Alexandra Hart.

Still sorting through the 850+ photos I shot today, a rough edit #Eclipse2017 pic.twitter.com/r4SC4YABtD

— Tony Rice (@rtphokie) August 21, 2017

The post Incredible Solar Eclipse Images From Our Readers appeared first on Universe Today.

Tales From Totality: Standing in the Shadow of the Moon

Tales From Totality: Standing in the Shadow of the Moon:

A brilliant diamond ring punctuates totality. Image credit and copyright: Shahrin Ahmad.

They came, they saw, they battled clouds, traffic and strange charger adapters in a strange land. Yesterday, millions stood in awe as the shadow of the Moon rolled over the contiguous United States for the first time in a century. If you’re like us, your social media feed is now brimming with amazing images of yesterday’s total solar eclipse.

Already, we’ve seen some amazing reader images at Universe Today, with more to come. As a special look at a unique event, we’ve collected reader testimonies from every state along the path of totality of just what the eclipse was like.

Enjoy!

Oregon- Shahrin Ahmad (@Shahgazer)

We drove from Dalles at 3 AM. Nearing the observation spot, we got a flat tire! It was 5:30 AM, and no phone line! I sent a text to the land owner and somehow it reached him and we managed to be there by 6:30 AM. We observed from a secluded spot about 30 miles from Madras, with a 2 minutes and 2 seconds of totality. The sky was really clear during sunrise, but as totality approached we got some thin clouds hovering in the east. Luckily, it was thin enough to not spoil anything. The corona was incredibly beautiful with longer (streamers) jutting out at the 4 and 8 o’clock position. The first and second diamond ring were spectacular with the eye, probably with the help with the thin clouds. We calculated about 7 degree drop in temperature. The shadow was enormous, engulfing Mt Hood from the west and flew past above us towards and towards the Sun. Mesmerizing! 2 minutes simply was not enough, since this is probably my best view of a total solar eclipse so far!

The bright star Regulus, tangled up in the solar corona. Image credit and copyright: Shahrin Ahmad.

(Note: to our knowledge, no one witnessed the brief moments of totality as the umbra of the Moon brushed tiny corners of Montana and Iowa… if you’re reading this and did so, let us know!)

Idaho- Bruce McCurdy (@BruceMcCurdy)

How to describe such a magnificent spectacle in a “brief paragraph”? Our group from Edmonton observed totality under clear skies near Birch Creek, Idaho. After the Moon’s silhouette inexorably progressed & gradually swallowed up an impressive line of sunspots, the pace of dynamic events picked up dramatically in the minutes surrounding totality. The temperature dropped noticeably. Light faded & became “flat” while shadows became better defined & lost their fuzzy edges (penumbrae). The Moon’s onrushing shadow became visible on the mountains to our west, while rapidly-moving shadow bands squiggled on the ground around us. The sky took on an eerie indigo hue as the last vestiges of direct sunlight were obscured. A new & temporary centrepiece emerged in the sky: the black circle of the lunar night side highlighted by a spectacular corona, its far-flung pearly-white streamers contained within sharply defined edges. Around the black limb fiery coral pink prominences added intense colour highlights to the scene. Just beyond the corona gleamed Regulus, closer to the Sun than is possible for any other star of first magnitude or brighter, while off to one side Venus shone brilliantly, far higher in the sky than its customary window of dominance in normal twilight. All too soon the right edge of the lunar silhouette brightened, then blossomed in a brilliant diamond ring that continued to intensify for a couple of glorious seconds until filters again became a must. By now the mountains to our east were in darkness as the umbral shadow receded from our immediate location, leaving a number of our small party in tears from the intensity of the experience.

Wyoming- Kelly Kizer Whitt (@Astronomommy)

We woke up in the Tetons Monday morning to a sky streaked with clouds. But the hourly weather report showed clearing, so we headed to our spot before 7 AM. We were able to secure parking by our preferred observing location, the Mormon Barn with a view of the iconic Teton range in the background. Looking east, we saw the clouds slink away to the south until skies were blue and clear, despite lingering haze and smoke on the northern horizon from wildfires.

Crescent Suns along with the Tetons. image credit and copyright: Kelly Kizer Whitt.

Having been a science writer for two decades, I was well versed on total solar eclipses even though I’d never seen one first hand. But it didn’t unfold quite as I expected. The sky and air didn’t take on a twilight quality until the Sun was well over halfway obscured. Then when darkness fell, it came fast and the temperature dropped hard. We had on our eclipse glasses and were staring at the Sun, waiting to see bailey’s beads or the diamond ring. But first I glanced down and saw the slithering, wiggling lines of darkness and light known as the shadow bands. They have a truly creepy quality as they dance in the growing dark. Then we looked back up as the sliver of orange disappeared and the Sun winked out from our glasses. Pulling them off, my family let out cries of surprise when they saw the black hole where the Sun had been, surrounded by the long, wispy, intricate corona. The eclipsed Sun and corona took up a much larger space in the sky than I expected, but the photo I took (just like when photographing a full moon) does not give a true representation of what you can see with your eyes.

I only took three photos because I wanted to just enjoy the view. I almost forgot to look for the stars. We saw a plane, Venus, and Sirius. Our eyes never adjusted enough to spot Jupiter or the others and the rosy glow of a false twilight brightened all horizons in a 360-degree ring. So soon it was over. The bailey’s beads and diamond ring we missed as the total eclipse began, and appeared to us instead at the end. These phenomena were a bright and beautiful warning to get our eclipse glasses back on. The world returned to daylight fairly quickly, but the drop in temperature lingered a bit longer. Our memories will last a lifetime.

Nebraska- (@BigBadEd)

Having doubtful cloud forecasts for Scottsbluff & Carhenge,  we met on a foggy morning in Sidney, Nebraska with thoughts of changing plans to Wyoming for clear skies. As the forecast improved,  15 of us set off for Carhenge.  We arrived before 7 AM to plentiful parking & a few hundred people. Towards 9 AM the crowds started to swell, including aliens, welders and the governor of Nebraska. Joined by more people & dogs, I estimate around 3,000 people were at the site. Some clouds went by at mid-coverage, casting a spectacular crescent. Clouds cleared, and cheers rose as we went into totality,  such a beautiful sight some were moved to tears as the diamond ring emerged. A thoroughly wonderful experience shared with friends and spellbound crowd, definitely worth the trip from Florida.

Kansas- Michelle Tevis (@MichelleKTevis)

I saw it (the eclipse) from Weston, Missouri, just northwest of the Kansas-Missouri line. Clouds and rain obscured the sun for most of the eclipse, but the rain subsided during totality and allowed us to get outside for the quick move into darkness. Even though we couldn’t see the eclipse or corona, the atmosphere took on a different feel. There was a change in how things were colored — as if you were looking through darker and darker polarized glasses, and the silence took on a feeling, like a deep vibration.

Missouri- Jeudy Blanco (@Jeudyx)

Totality from Missouri. Image credit and copyright: Jeudy Blanco.

It was amazing. We changed plans last night, instead of going to St Joseph we drove to Columbia. I was really worried the first few minutes of the eclipse because it was cloudy, my PST couldn’t resolve the image of the Sun! But quickly the clouds dispersed. We were on a property from the family of my friend, around 25 people of all ages. When it was around 70% (partial) you could feel in the environment that something was going on. Everything got a lot more quiet and the temperature dropped. Everybody was trying to get pictures of the Sun with their phones on the PST. Then totality started, it was indescribable for me. I was seeing the Sun’s corona with my bare eyes. I was really nervous and anxious, actually. We could see Venus near the Sun. Everybody was super excited, I almost cried. The experience was amazing, a total success, the long trip was worth it.

Illinois- The Universe Today expedition to the Prairie State led by Publisher Fraser Cain also managed to catch a brief glimpse of totality through a gap in the clouds:

Can’t believe our luck. Hole in the clouds opened up right in time. I’m hooked! @Karlaii got it on camera. #eclipse2017 pic.twitter.com/Vu9Annq14t

— Fraser Cain (@fcain) August 21, 2017

Kentucky- Mike Weasner (@Mweasner)

Earthshine (!) on the Moon, seen during totality. Image credit and copyright: Mike Weasner.

About 400 eclipse enthusiasts from around the world including me were part of a Sky and Telescope tour group. We were at Hopkinsville Community College located in Hopkinsville, Kentucky, where totality lasted 2 minutes and 40 seconds, which was too short. We arrived at the viewing site about 4.5 hours before First Contact. Traffic was surprisingly light. There were a few thin clouds but nothing significant. Anticipation was high. Many of us set up cameras and were ready well before First Contact. First Contact occurred with a clear sky, and the sky stayed mostly clear until about 30 minutes before Second Contact. Then a large cloud covered the Sun. Fortunately the cloud moved on within a couple of minutes and the sky was mostly clear through Fourth Contact. Totality was beautiful. Most people saw Venus, some saw Jupiter too, but no one seems to have seen any stars although it did get dark at the site. Many people in the group left soon after totality ended, but I and several others stayed to view and photograph the eclipse through Fourth Contact. 

Tennessee- (Terry Horne @CapH_1)

My wife and I viewed the event from Sheep Barn Ridge, which is a few miles from Kingston, TN. We began the planning in late 2015 when we realized the shadow path was adjacent to our property near my folks in TN. Our location delivered 2 minutes and 29 seconds of totality, with clear skies, a valley pasture view among new friends, goats, llama, ducks, chickens and a few hounds.

We experienced every awe & oddity we had studied during the ramp up to the event. My wife did an excellent job with her photo efforts. She balanced her personal viewing time and planned equipment duties well. This was a source of much worry and discussion during the months prior.

I’ll mention a few surprises. I was impressed by the amount of light cast on the landscape with barely a sliver of the Sun remaining. I suspect the ambient sunlight to the south east was the major source. The rapid transition to peak darkness was dramatic.

In contrast, I noticed a clear reduction of heat radiation on my skin with about 50% coverage. It was a hot day. I wished I’d had more time to observe the animals.

I found it somewhat humorous how many folks took all of the important PSA’s about retina damage to heart. Before totality they bowed their heads to the ground when they did not have their gasses on while walking, standing and sitting.

What I learned most was, to the inexperienced, East Tennessee Moonshine travels faster than the Moon’s shadow.

Be careful!

Georgia- Jeannette Iriye (@i_fridrich)

We found a lovely scenic overlook facing west in Sky Valley, just outside Dillard, Georgia. Skies were clear with only minimal cloud cover until about 13:30, when heavy cloud cover began to build in the south/southeast. The clouds obfuscated the remainder of our view of the eclipse directly. It did get much cooler, windy, and the crickets were singing just prior to and during totality.

A partially eclipsed Sun versus clouds. Image credit and copyright: Jeannette Iriye.

South Carolina- Terri (@wizbee1)

We didn’t make it to South Carolina, and had to turn the plane back because of weather. Watched instead from Saint Mary’s Georgia. Did feel the temperature drop and experienced darkening but not in totality.

And us? We watched from the Pisgah Astronomical Research Institute in North Carolina as the shadow of the Moon draped over the landscape. The rolling afternoon clouds afforded only brief glimpses of the partially eclipsed Sun. Then, just prior to totality, we caught the final moments as the Sun withered to a brief diamond ring flash… and was gone. Magic! Unfortunately, the corona remained hidden behind high clouds for the 107 seconds of darkness, though we were treated to an unworldly 360 degree sunset below the cloud deck. Nocturnal mosquitoes, fooled by the false dusk, began their rounds, as a light “eclipse wind” kicked up.

Author and wife (@MyschaTheriault) standing in the shadow of the Moon, plus our view from the Pisgah Astronomical Research Institute (PARI) just before totality. Thanks to @Dayveesutton for snapping the pic!

Then, it was over. Got the eclipse bug? Well, another total solar eclipse crosses the U.S. in 2024… but you don’t have to wait that long, as we’ve got one coming right up crossing Argentina and Chile on July 2^nd, 2019…

I’ll see you there!

The post Tales From Totality: Standing in the Shadow of the Moon appeared first on Universe Today.

Hallelujah, It’s Raining Diamonds! Just like the Insides of Uranus and Neptune.

Hallelujah, It’s Raining Diamonds! Just like the Insides of Uranus and Neptune.:

For more than three decades, the internal structure and evolution of Uranus and Neptune has been a subject of debate among scientists. Given their distance from Earth and the fact that only a few robotic spacecraft have studied them directly, what goes on inside these ice giants is still something of a mystery. In lieu of direct evidence, scientists have relied on models and experiments to replicate the conditions in their interiors.

For instance, it has been theorized that within Uranus and Neptune, the extreme pressure conditions squeeze hydrogen and carbon into diamonds, which then sink down into the interior. Thanks to an experiment conducted by an international team of scientists, this “diamond rain” was recreated under laboratory conditions for the first time, giving us the first glimpse into what things could be like inside ice giants.

The study which details this experiment, titled “Formation of Diamonds in Laser-Compressed Hydrocarbons at Planetary Interior Conditions“, recently appeared in the journal Nature Astronomy. Led by Dr. Dominik Kraus, a physicist from the Helmholtz-Zentrum Dresden-Rossendorf Institute of Radiation Physics, the team included members from the SLAC National Accelerator Laboratory, the Lawrence Livermore National Laboratory and UC Berkeley.

Uranus and Neptune, the Solar System’s ice giant planets. Credit: Wikipedia Commons

For decades, scientists have held that the interiors of planets like Uranus and Neptune consist of solid cores surrounded by a dense concentrations of “ices”. In this case, ice refers to hydrogen molecules connected to lighter elements (i.e. as carbon, oxygen and/or nitrogen) to create compounds like water and ammonia. Under extreme pressure conditions, these compounds become semi-solid, forming “slush”.

And at roughly 10,000 kilometers (6214 mi) beneath the surface of these planets, the compression of hydrocarbons is thought to create diamonds. To recreate these conditions, the international team subjected a sample of polystyrene plastic to two shock waves using an intense optical laser at the Matter in Extreme Conditions (MEC) instrument, which they then paired with x-ray pulses from the SLAC’s Linac Coherent Light Source (LCLS).

As Dr. Kraus, the head of a Helmholtz Young Investigator Group at HZDR, explained in an HZDR press release:

“So far, no one has been able to directly observe these sparkling showers in an experimental setting. In our experiment, we exposed a special kind of plastic – polystyrene, which also consists of a mix of carbon and hydrogen – to conditions similar to those inside Neptune or Uranus.”

The plastic in this experiment simulated compounds formed from methane, a molecule that consists of one carbon atom bound to four hydrogen atoms. It is the presence of this compound that gives both Uranus and Neptune their distinct blue coloring. In the intermediate layers of these planets, it also forms hydrocarbon chains that are compressed into diamonds that could be millions of karats in weight.

The MEC hutch of SLAC’s LCLS Far Experiement Hall. Credit: SLAC National Accelerator Laboratory

The optical laser the team employed created two shock waves which accurately simulated the temperature and pressure conditions at the intermediate layers of Uranus and Neptune. The first shock was smaller and slower, and was then overtaken by the stronger second shock. When they overlapped, the pressure peaked and tiny diamonds began to form. At this point, the team probed the reactions with x-ray pulses from the LCLS.

This technique, known as x-ray diffraction, allowed the team to see the small diamonds form in real-time, which was necessary since a reaction of this kind can only last for fractions of a second. As Siegfried Glenzer, a professor of photon science at SLAC and a co-author of the paper, explained:

“For this experiment, we had LCLS, the brightest X-ray source in the world. You need these intense, fast pulses of X-rays to unambiguously see the structure of these diamonds, because they are only formed in the laboratory for such a very short time.”

In the end, the research team found that nearly every carbon atom in the original plastic sample was incorporated into small diamond structures. While they measured just a few nanometers in diameter, the team predicts that on Uranus and Neptune, the diamonds would be much larger. Over time, they speculate that these could sink into the planets’ atmospheres and form a layer of diamond around the core.

The interior structure of Neptune. Credit: Moscow Institute of Physics and Technology

In previous studies, attempts to recreate the conditions in Uranus and Neptune’s interior met with limited success. While they showed results that indicated the formation of graphite and diamonds, the teams conducting them could not capture the measurements in real-time. As noted, the extreme temperatures and pressures that exist within gas/ice giants can only be simulated in a laboratory for very short periods of time.

However, thanks to LCLS – which creates X-ray pulses a billion times brighter than previous instruments and fires them at a rate of about 120 pulses per second (each one lasting just quadrillionths of a second) – the science team was able to directly measure the chemical reaction for the first time. In the end, these results are of particular significance to planetary scientists who specialize in the study of how planets form and evolve.

As Kraus explained, it could cause to rethink the relationship between a planet’s mass and its radius, and lead to new models of planet classification:

“With planets, the relationship between mass and radius can tell scientists quite a bit about the chemistry. And the chemistry that happens in the interior can provide additional information about some of the defining features of the planet… We can’t go inside the planets and look at them, so these laboratory experiments complement satellite and telescope observations.”

This experiment also opens new possibilities for matter compression and the creation of synthetic materials. Nanodiamonds currently have many commercial applications – i.e. medicine, electronics, scientific equipment, etc, – and creating them with lasers would be far more cost-effective and safe than current methods (which involve explosives).

Fusion research, which also relies on creating extreme pressure and temperature conditions to generate abundant energy, could also benefit from this experiment. On top of that, the results of this study offer a tantalizing hint at what the cores of massive planets look like. In addition to being composed of silicate rock and metals, ice giants may also have a diamond layer at their core-mantle boundary.

Assuming we can create probes of sufficiently strong super-materials someday, wouldn’t that be worth looking into?

Further Reading: SLAC, HZDR, Nature Astronomy



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Mars Express Captures Mars’ Moving Bow Shock

Mars Express Captures Mars’ Moving Bow Shock:

Every planet in our Solar System interacts with the stream of energetic particles coming from our Sun. Often referred to as “solar wind”, these particles consist mainly of electrons, protons and alpha particles that are constantly making their way towards interstellar space. Where this stream comes into contact with a planet’s magnetosphere or atmosphere, it forms a region around them known as a “bow shock”.

These regions form in front of the planet, slowing and diverting solar wind as it moves past – much like how water is diverted around a boat. In the case of Mars, it is the planet’s ionosphere that provides the conductive environment necessary for a bow shock to form. And according to a new study by a team of European scientists, Mars’ bow shock shifts as a result of changes in the planet’s atmosphere.

The study, titled “Annual Variations in the Martian Bow Shock Location as Observed by the Mars Express Mission“, appeared in the Journal of Geophysical Letters: Space Physics. Using data from the Mars Express orbiter, the science team sought to investigate how and why the bow shock’s location varies during the course of several Martian years, and what factors are chiefly be responsible.

Diagram of Mars’ orbit and changes to its bow shock between perihelion and aphelion. Credit: ESA/ATG medialab

For many decades, astronomers have been aware that bow shocks form upstream of a planet, where interaction between solar wind and the planet causes energetic particles to slow down and gradually be diverted. Where the solar wind meets the planet’s magnetosphere or atmosphere, a sharp boundary line is formed, which them extends around the planet in a widening arc.

This is where the term bow shock comes from, owing to its distinctive shape. In the case of Mars, which does not have a global magnetic field and a rather thin atmosphere to boot (less than 1% of Earth’s atmospheric pressure at sea level), it is the electrically-charged region of the upper atmosphere (the ionosphere) that is responsible for creating the bow shock around the planet.

At the same time, Mars relatively small size, mass and gravity allows for the formation of an extended atmosphere (i.e. an exosphere). In this portion of Mars’ atmosphere, gaseous atoms and molecules escape into space and interact directly with solar wind. Over the years, this extended atmosphere and Mars’ bow shock have been observed by multiple orbiter missions, which have detected variations in the latter’s boundary.

This is believed to be caused by multiple factors, not the least of which is distance. Because Mars has an relatively eccentric orbit (0.0934 compared to Earth’s 0.0167), its distance from the Sun varies quite a bit – going from 206.7 million km (128.437 million mi; 1.3814 AU) at perihelion to 249.2 million km (154.8457 million mi; 1.666 AU) at aphelion.

Illustration showing how Mars and Earth interact with solar wind. Credit: NASA

When the planet is closer, the dynamic pressure of the solar wind against its atmosphere increases. However, this change in distance also coincides with increases in the amount of incoming extreme ultraviolet (EUV) solar radiation. As a result, the rate at which ions and electrons (aka. plasma) are produced in the upper atmosphere increases, causing increased thermal pressure that counteracts the incoming solar wind.

Newly-created ions within the extended atmosphere are also picked up and accelerated by the electromagnetic fields being carried by the solar wind. This has the effect of slowing it down and causing Mars’ bowshock to shift its position. All of this has been known to happen over the course of a single Martian year – which is equivalent to 686.971 Earth days or 668.5991 Martian days (sols).

However, how it behaves over longer periods of time is a question that was previously unanswered. As such, the team of European scientists consulted data obtained by the Mars Express mission over a five year period. This data was taken by the Analyser of Space Plasma and EneRgetic Atoms (ASPERA-3) Electron Spectrometer (ELS), which the team used to examine a total of 11,861 bow shock crossings.

What they found was that, on average, the bow shock is closer to Mars when it is near aphelion (8102 km), and further away at perihelion (8984 km). This works out to a variation of about 11% during the Martian year, which is pretty consistent with its eccentricity. However, the team wanted to see which (if any) of the previously-studied mechanisms was chiefly responsible for this change.

The moving Martian bow shock. Credit: ESA/ATG medialab

Towards this end, the team considered variations in solar wind density, the strength of the interplanetary magnetic field, and solar irradiation as primary causes – are all of which decline as the planet gets farther away from the Sun. However, what they found was that the bow shock’s location appeared more sensitive to variations in the Sun’s output of extreme UV radiation rather than to variations in solar wind itself.

The variations in bow shock distance also appeared to be related to the amount of dust in the Martian atmosphere. This increases as Mars approaches perihelion, causing the atmosphere to absorb more solar radiation and heat up. Much like how increased levels of EUV leads to an increased amount of plasma in the ionosphere and exosphere, increased amounts of dust appear to act as a buffer against solar wind.

As Benjamin Hall, a researcher at Lancaster University in the UK and the lead author of the paper, said in an ESA press release:

“Dust storms have been previously shown to interact with the upper atmosphere and ionosphere of Mars, so there may be an indirect coupling between the dust storms and bow shock location… However, we do not draw any further conclusions on how the dust storms could directly impact the location of the Martian bow shock and leave such an investigation to a future study.”

http://sci.esa.int/science-e-media/video/e6/108_Mars_BowShock_3d_512p24.mp4

In the end, Hall and his team could not single out any one factor when addressing why Mars’ bow shock shifts over longer periods of time. “It seems likely that no single mechanism can explain our observations, but rather a combined effect of all of them,” he said. “At this point none of them can be excluded.”

Looking ahead, Hall and his colleagues hope that future missions will help shed additional light on the mechanisms behind Mars shifting bowshock. As Hall indicated, this will likely involve “”joint investigations by ESA’s Mars Express and Trace Gas Orbiter, and NASA’s MAVEN mission. Early data from MAVEN seems to confirm the trends that we discovered.”

While this is not the first analysis that sought to understand how Mars’ atmosphere interacts with solar wind, this particular analysis was based on data obtained over a much longer period of time than any previously study. In the end, the multiple missions that are currently studying Mars are revealing much about the atmospheric dynamics of this planet. A planet which, unlike Earth, has a very weak magnetic field.

What we learn in the process will go a long way towards ensuring that future exploration missions to Mars and other planets that have weak magnetic fields (like Venus and Mercury) are safe and effective. It might even assist us with the creation of permanent bases on these worlds someday!

Further Reading: ESA, Journal of Geophysical Research: Space Physics

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