Saturday, September 13, 2014

WONDERFUL PHOTOS Guide to Tonight’s Big Harvest Moon

Guide to Tonight’s Big Harvest Moon:



"The Harvest Moon", a circa 1833 oil painting by Samuel Palmer. Closely spaced moonrises meant extra light to bring in the crops in the days before electric lighting.

“The Harvest Moon”, a circa 1833 oil painting by Samuel Palmer. Closely spaced moonrises meant extra light to bring in the crops in the days before electric lighting.
Tonight, September 8, the Harvest Moon rises the color of a fall leaf and spills its light across deserts, forests, oceans and cities. The next night it rises only a half hour later. And the next, too. The short gap of time between successive moonrises gave farmers in the days before electricity extra light to harvest their crops, hence the name.

The Harvest Moon is the full moon that falls closest to the autumnal equinox, the beginning of northern autumn. As the moon orbits the Earth, it moves eastward about one fist held at arm’s length each night and rises about 50 minutes later. You can see its orbital travels for yourself by comparing the moon’s nightly position to a bright star or constellation.

This full Moon is also a Proxigean or Perigee Full “Supermoon” (find out more about that here), which means the Moon is in a spot in its elliptical orbit where it is closer to Earth near the time it is full, making it look up to 15% larger than average full Moon.



Around the time of Harvest Moon, the full moon's path is tilted at a shallow angle to the eastern horizon making with successive moonrises only about a half hour apart instead of the usual 50 minutes. Source: Stellarium

Around the time of Harvest Moon, the full moon’s path is tilted at a shallow angle to the eastern horizon making with successive moonrises only about a half hour apart instead of the usual 50 minutes. Source: Stellarium
50 minutes is the usual gap between moonrises. But it can vary from 25 minutes to more than an hour depending upon the angle the moon’s path makes to the eastern horizon at rise time. In September that path runs above the horizon at a shallow angle. As the moon scoots eastward, it’s also moving northward this time of year.

This northward motion isn’t as obvious unless you watch the moon over the coming week. Then you’ll see it climb to the very top of its monthly path when it’s high overhead at dawn. The northward motion compensates for the eastward motion, keeping the September full moon’s path roughly parallel to the horizon with successive rise times only ~30 minutes apart.

The angle of the moon’s path to the horizon makes all the difference in moonrise times. At full phase in spring, the path tilts steeply southward, delaying successive moonrises by over an hour. In September, the moon’s path is nearly parallel to the horizon with successive moonrises just 20+ minutes apart. Times are shown for the Duluth, Minn. region. Illustration: Bob King

The angle of the moon’s path to the horizon makes all the difference in moonrise times. At full phase in spring, the path tilts steeply southward, delaying successive moonrises by over an hour. In September, the moon’s path is nearly parallel to the horizon with successive moonrises just 30+ minutes apart. Times are shown for the Duluth, Minn. region. Illustration: Bob King
Exactly the opposite happened 6 months earlier this spring, when the moon’s path met the horizon at a steep angle. While it traveled the identical distance each night then as now, its tilted path dunked it much farther below the horizon night to night. The spring full moon moves east and south towards its lowest point in the sky. Seen from the northern hemisphere, that southward travel adds in extra time for the moon to reach the horizon and rise each successive night.

If all this is a bit mind-bending, don’t sweat it. Click HERE to find when the moon rises for your town and find a spot with a great view of the eastern horizon. You’ll notice the moon is orange or red at moonrise because the many miles of thicker atmosphere you look through when you gaze along the horizon scatters the shorter bluer colors from moonlight, tinting it red just as it does the sun.

A series of photos of the full moon setting over Earth's limb taken by from space by NASA astronaut Don Pettit on April 16, 2003. Refraction causes a celestial object's light to be bent upwards, so it appears higher than it actually is. The bottom half of the moon, closer to the horizon, is refracted strongest and "pushed" upward into the top half, making it look squished. Credit: NASA

A series of photos of the full moon setting over Earth’s limb taken by from space by NASA astronaut Don Pettit on April 16, 2003. Refraction causes a celestial object’s light to be bent upwards, so it appears higher than it actually is. The bottom half of the moon, closer to the horizon, is refracted strongest and “pushed” upward into the top half, making it look squished. Credit: NASA
The moon will also appear squished due to atmospheric refraction. Air is densest right at the horizon and refracts or bends light more strongly than the air immediately above it. Air “lifts” the bottom of the moon – which is closer to the horizon – more than the top, squishing the two halves together into an egg or oval shape.

How we perceive the moon's size may have much to do with what's around it. In this illustration, most of us seen the bottom moon as smaller, but they're both exactly the same size. Crazy, isn't it? Credit: NASA

How we perceive the moon’s size may have much to do with what’s around it. In this illustration, most of us seen the bottom moon as smaller, but they’re both exactly the same size. Crazy, isn’t it? Credit: NASA
You may also be entranced Monday night by the Moon Illusion, where the full moon appears unnaturally large when near the horizon compared to when viewed higher up. No one has come up with a complete explanation for this intriguing aspect of our perception, but the link above offers some interesting hypotheses.

Can you see craters with your naked eye? Yes! Try tonight through Wednesday night. Plato is the trickiest. Credit: Bob King

Can you see craters with your naked eye? Yes! Try tonight through Wednesday night. Plato is the trickiest. Credit: Bob King
Finally, full moon is an ideal time to see several lunar craters with the naked eye. They’re not the biggest, but all, except Plato, are surrounded by bright rays of secondary impact craters that expand their size and provide good contrast against the darker lunar “seas”. Try with your eyes alone first, and if you have difficulty, use binoculars to get familiar with the landscape and then try again with your unaided eyes.

In contrast to the other craters, Plato is dark against a bright landscape. It’s a true challenge – I’ve tried for years but still haven’t convinced myself of seeing it. The others are easier than you’d think. Good luck and clear skies!

Tagged as:
full moon,
harvest moon,
Moon Illusion,
refraction
Posted by Nelio Inacio at 6:15 AM 0 comments

Gliese 15Ab: The Closest Known Super-Earth?

Gliese 15Ab: The Closest Known Super-Earth?:



An artist’s rendering of the newly discovered exoplanet OGLE-2013-BLG-0341LBb (far right) orbiting one star (right) of a binary red dwarf star system, from an Earth-type distance of approximately 0.9 Astronomical Units away. Image Credit: Cheongho Han, Chungbuk National University, Republic of Korea

An artist’s conception of the view from an exoplanet orbiting one star in a binary red dwarf system. Image Credit: Cheongho Han, Chungbuk National University, Republic of Korea
Our solar neighborhood is rich with planetary systems. Within 20 light-years we’ve detected sizzling gas giants and rocky planets orbiting closer to their host star than Mercury orbits the Sun.

Astronomers have now added one more to the list, and this one — a super-Earth dubbed Gliese 15Ab — ranks as one of the closest known exoplanets, circling its host star only 11.7 light-years away.

Gliese 15 is a binary system, with two cool, dim red dwarfs orbiting each other. Although red dwarfs are the most common type of star in the galaxy, they’re so intrinsically faint that not a single one (including the closest star to the Sun, Proxima Centauri) is visible to the naked eye.

Although Gliese 15A might appear faint from Earth, it is overwhelmingly bright compared to its barely reflective exoplanet. So unfortunately we can’t easily see the exoplanet directly. But it does leave an imprint on its host star. Its small gravitational tug makes Gliese 15A wobble ever so slightly as both orbit a mutual center of mass, known as the barycenter.

The star’s movement is then imprinted on its spectrum. As Gliese 15A moves away from the Earth, its spectral lines stretch to redder wavelengths. But as it moves toward the Earth, its spectral lines compress to shorter wavelengths.

Screen Shot 2014-09-08 at 3.52.34 PM

The radial velocities for Gliese 15Ab. Image Credit: Howard et al.
The change is minute. But the Keck 10-meter telescope, with an extremely high-resolution detector, can see such small changes. And from this tiny wobble, Andrew Howard and colleagues calculated that the planet is 5.35 times the mass of Earth and orbits its star in only 11.44 days, making it a hot super-Earth. And remember, it’s only 11.7 light-years away.

A handful of other planet candidates have been found that are closer, but all — including Gliese 15Ab — have yet to be confirmed by other research teams. In the long run, it may turn out that this hot super-Earth is the closest planet to our pale blue dot. Then again, it may not. That’s how science works.

Nonetheless, Gliese 15Ab might prove to be an exciting target for one of the new planet imagers that came online within the past year.

The findings will be published in the Astrophysical Journal and are available online.

Tagged as:
Gliese 15,
super earth
Posted by Nelio Inacio at 6:13 AM 0 comments

How Dark Matter Could Reduce The Fleet Of Galaxies Following The Milky Way

How Dark Matter Could Reduce The Fleet Of Galaxies Following The Milky Way:



On either side of the white line in the picture are two models of how dark matter is distributed in a galaxy similar to the Milky Way. At left, non-interacting cold dark matter creates satellite galaxies. At right, dark matter interacting with other particles makes the number of observed satellite galaxies smaller. Credit: Durham University

On either side of the white line in the picture are two models of how dark matter is distributed in a galaxy similar to the Milky Way. At left, non-interacting cold dark matter creates satellite galaxies. At right, dark matter interacting with other particles makes the number of observed satellite galaxies smaller. Credit: Durham University
Funny how small particle interactions can have such a big effect on the neighbors of the Milky Way. For a while, scientists have been puzzled about the dearth of small satellite galaxies surrounding our home galaxy.

They thought that cold dark matter in our galaxy should encourage small galaxies to form, which created a puzzle. Now, a new set of research suggests the dark matter actually interacted with small bits of normal matter (photons and neutrinos) and the dark matter scattered away, reducing the amount of material available for building galaxies.

“We don’t know how strong these interactions should be, so this is where our simulations come in,” stated Celine Boehm, a particle physicist at Durham University who led the research. “By tuning the strength of the scattering of particles, we change the number of small galaxies, which lets us learn more about the physics of dark matter and how it might interact with other particles in the Universe.”

Artist's conception of the Milky Way galaxy based on the latest survey data from ESO’s VISTA telescope at the Paranal Observatory. A prominent bar of older, yellower stars lies at galaxy center surrounded by a series of spiral arms. The galaxy spans some 100,000 light years. Credit: NASA/JPL-Caltech, ESO, J. Hurt

Artist’s conception of the Milky Way galaxy based on the latest survey data from ESO’s VISTA telescope at the Paranal Observatory. A prominent bar of older, yellower stars lies at galaxy center surrounded by a series of spiral arms. The galaxy spans some 100,000 light years. Credit: NASA/JPL-Caltech, ESO, J. Hurt
Dark matter is a poorly understood part of the Universe, which is frustrating for scientists because it (along with dark energy) is believed to make up the majority of our Cosmos. There are several postulated types of it, but the main thing to understand is dark matter is hard to detect (except, in certain cases, through its interactions with gravity.)

This isn’t the only explanation for why the galaxies are missing, the scientists caution. Perhaps the universe’s first stars were so hot that they affected the gas that other stars formed from, for example.

A paper on the research was published in the Monthly Notices of the Royal Astronomical Society and is also available in preprint version on Arxiv.

Source: Royal Astronomical Society

Tagged as:
Dark Matter
Posted by Nelio Inacio at 6:12 AM 0 comments

AMAZING PHOTO : Spectacular View of the Rosette Nebula

Astrophoto: Spectacular View of the Rosette Nebula:



The Rosette Nebula, taken on September 9, 2014. A 5 hour exposure, using an Epsilon 180 ED telescope, with filters of 3nm Astrodon combining Hydrogen-alpha, Oxygen and Sulfur II. Credit and copyright: César Cantú.

The Rosette Nebula, taken on September 9, 2014. A 5 hour exposure, using an Epsilon 180 ED telescope, with filters of 3nm Astrodon combining Hydrogen-alpha, Oxygen and Sulfur II. Credit and copyright: César Cantú.
Wow! Here’s a gorgeous view of the Rosette Nebula from astrophotographer César Cantú. The Rosette Nebula is a star-forming region about 5,000 light years from Earth, located in the constellation Monoceros. Winds from the young, hot, blue stars cleared the central hole. The central cluster of stars is also known as NGC 2244.

The image compiles about 5 hours of observing time and César used hydrogen-alpha, oxygen and sulfur filters.

Compare this new view to earlier images of the Rosette taken by César in 2011, and see more at his website, Astronomía Y Astrofotografía..



Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.

Tagged as:
Astrophotos,
César Cantu,
Rosette Nebula
Posted by Nelio Inacio at 6:11 AM 0 comments

Will Aurora Strike Tonight? Here’s What to Expect

Will Aurora Strike Tonight? Here’s What to Expect:



A bright arc and pink-topped rays stipple the northern sky and cross the Bowl of the Big Dipper last night around 11:30 p.m. CDT over Caribou Lake north of Duluth, Minn. Credit: Guy Sander

A bright arc and pink-topped rays stipple the northern sky and light up the Bowl of the Big Dipper last night around 11:30 p.m. CDT over Caribou Lake north of Duluth, Minn. Credit: Guy Sander
Auroras showed up as forecast last night beginning around nightfall and lasting until about 1 a.m. CDT this morning. Then the action stopped. At peak, the Kp index dinged the bell at “5” (minor geogmagnetic storm) for about 6 hours as the incoming shock from the arrival of the solar blast rattled Earth’s magnetosphere. It wasn’t a particularly bright aurora and had to compete with moonlight, so many of you may not have seen it. You needn’t worry. A much stronger G3 geomagnetic storm from the second Earth-directed coronal mass ejection (CME) remains in the forecast for tonight.

Plot showing the Kp index of magnetic activity high in the Earth's magnetic domain called the magnetosphere. The two red bars show the Kp at '5' last night and early this morning (dotted line represents 0 UT or 7 p.m. CDT). Inset is the current detailed forecast in 3-hour increments. Credit: NOAA

Plot showing the Kp index of magnetic activity high in the Earth’s magnetic domain called the magnetosphere. The two red bars show the Kp at ‘5’ last night and early this morning (dotted line represents 0 UT or 7 p.m. CDT). Inset is the current detailed forecast in Universal Time (Greenwich Time) in 3-hour increments. Credit: NOAA
Activity should begin right at nightfall and peak between 10 p.m. and 1 a.m. Central Daylight Time. The best place to observe the show is from a location well away from city lights with a good view of the northern sky. Auroras are notoriously fickle, but if the NOAA space forecasting crew is on the money, flickering lights should be visible as far south as Illinois and Kansas. The storm also has the potential to heat and expand the outer limits of Earth’s atmosphere enough to cause additional drag on low-Earth-orbiting (LEO) satellites. High-frequency radio transmissions like shortwave radio may be reduced to static particularly on paths crossing through the polar regions.

Earth’s magnetic bubble, generated by motions within its iron-nickel core and shaped by the solar wind, is called the magnetosphere. It extends some 40,000 miles forward of the planet and more than 3.9 million miles in the tailward direction. Credit: NASA

Earth’s magnetic bubble, generated by motions within its iron-nickel core and shaped by the solar wind, is called the magnetosphere. It extends some 40,000 miles forward of the planet and more than 3.9 million miles in the tailward direction. Most of the time it sheds particle blasts from the sun called coronal mass ejections, but occasionally one makes it past our defenses and we get an auroral treat. Credit: NASA
If you study the inset box in the illustration above, you can see that from 21-00UT (4 -7 p.m. Central time) the index jumps quickly form “3” to “6” as the blast from that second, stronger X-class flare (September 10) slams into our magnetosphere. Assuming the magnetic field it carries points southward, it should link into our planet’s northward-pointing field and wreak beautiful havoc. A G2 storm continues through 10 p.m. and then elevates to Kp 7 or G3 storm between 10 p.m. and 1 a.m. before subsiding slightly in the wee hours before dawn. The Kp index measures how disturbed Earth’s magnetic field is on a 9-point scale and is compiled every 3 hours by a network of magnetic observatories on the planet.

A lovely rayed arc reflected in Caribou Lake north of Duluth, Minn. on September 11, 2014. Credit: Guy Sander

A lovely rayed arc reflected in Caribou Lake north of Duluth, Minn. on September 11, 2014. Tonight the moon rises around 9:30 p.m. The lower in the sky it is, the brighter the aurora will appear. Hopefully tonight’s lights will outdo what the moon can dish out. Credit: Guy Sander
All the numbers are lined up. Now, will the weather and solar wind cooperate?  Stop back this evening as I’ll be updating with news as the storm happens.

The auroral oval around 2:30 p.m. CDT this afternoon September 12 shows a southward expansion into the Scandinavian countries. Click for current map. Credit: NOAA

The auroral oval around 2:30 p.m. CDT this afternoon September 12 shows a southward expansion into the Scandinavian countries and Russia and Iceland. Where the sky is dark, auroras are typically seen anywhere under or along the edge of the oval. Click for current map. Credit: NOAA
Tagged as:
aurora,
auroral oval,
Kp index,
magnetosphere,
northern lights
Posted by Nelio Inacio at 6:08 AM 0 comments

How to Take Great Pictures of the Northern Lights

How to Take Great Pictures of the Northern Lights:

A group of amateur photographers set up on a beach on Lake Superior near Duluth to photograph the northern lights. To shoot the aurora you'll need a tripod and middle to high end digital camera. Pocket cameras work well in daylight and can be used to shoot bright northern lights, but the images will be noisy. Credit: Bob King

A group of amateur photographers take pictures of an aurora display from a beach along Lake Superior near Duluth. To shoot the aurora you’ll need a tripod and middle to high end digital camera. Pocket cameras work well in daylight and can be used to shoot bright northern lights, but the images will be noisy. Credit: Bob King
Everybody loves pictures of the northern lights? If you’ve never tried to shoot the aurora yourself but always wanted to, here are a few tips to get you started.

"T" stands for a terrific aurora seen last winter from near Duluth, Minn. US. Photo taken with a high-end digital camera (Canon Eos 1 Mark III) at ISO 800, 30-second exposure. Credit: Bob King

“T” stands for a terrific aurora seen last winter near Duluth, Minn. U.S. Photo taken with a high-end digital camera (Canon EOS 1-D Mark III) at ISO 800, 30-second exposure. Credit: Bob King
The strong G3 geomagnetic storm expected tonight should kick out a reasonably bright display, perfect for budding astrophotographers. Assuming the forecasters are correct, you’ll need a few things. A location with a nice open view to the north is a good start. The aurora has several different active zones. There are bright, greenish arcs, which loll about the northern horizon, parallel rays midway up in the northern sky and towering rays and diffuse aurora that can surge past the zenith. Often the aurora hovers low and remains covered by trees or buildings, so find a road or field with good exposure.

15-second time exposure of Vega rising taken with a typical digital pocket camera. Notice the grainy texture. Credit: Bob King

15-second time exposure of Vega rising taken with a typical digital pocket camera. Notice the grain or noise throughout. Credit: Bob King
Second, a tripod. You can do so much with this three-legged beast. No better astro tool in the universe. Even the brightest auroras will require a time exposure of at least 5 seconds. Since no human can be expected to hold a camera steady that long, a tripod is a necessity. After that, it comes down to a camera. Most “point-and-shoot” models have limited time exposure ability, often just 15 seconds. That may be long enough for brighter auroras, but to compensate, you’ll have to increase your camera’s sensitivity to light by increasing the “speed” or ISO. The higher you push the ISO, the grainier the images appear especially with smaller cameras. But you’ll be able to get an image, and that may be satisfaction enough.

I use a Canon EOS-1 Mark III camera to shoot day and night. While not the latest model, it does a nice job on auroras. The 16-35mm zoom wide-angle lens is my workhorse as the aurora often covers a substantial amount of sky. My usual routine is to monitor the sky. If I see aurora padding across the sky, I toss the my equipment in the car and drive out to one of several sites with a clear exposure to the north. Once the camera meets tripod, here’s what to do:

A bright, very active aurora. I used my zoom lens at 16mm at f/2.8 and a 15-second exposure at ISO 800.

A bright, active aurora. I used my zoom lens at 16mm at f/2.8 and about a 15-second exposure at ISO 800. Credit: Bob King
* Put the camera in manual mode and make sure my focus is set to infinity. Focusing is critical or the stars will look like blobs and the aurora green mush. There are a couple options. Use autofocus on a cloud or clouds in the daytime or the moon at night. Both are at “infinity” in the camera’s eye. Once focused at infinity, set the camera to manual and leave it there the rest of the evening to shoot the aurora. OR … note where the little infinity symbol (sideways 8) is on your lens barrel and mark it with a thin sharpie so you can return to it anytime. You can also use your camera in Live View mode, the default viewing option for most point-and-shoot cameras where you compose and frame live. Higher-end cameras use a viewfinder but have a Live View option in their menus. Once in Live View, manually focus on a bright star using the back of the camera. On higher-end cameras you can magnify the view by pressing on the “plus” sign. This allows for more precision focus.

* Set the lens to its widest open setting, which for my camera is f/2.8. The lower the f-stop number, the more light allowed in and the shorter the exposure. Like having really big pupils! You want to expose the aurora in as short a time as possible because it moves. Longer exposures soften its appearance and blur exciting details like the crispness of the rays.

My friend Glenn takes a night sky shot silhouetted against the northern lights. Credit: Bob King

A friend takes a night sky shot silhouetted against the glow of the northern lights. Credit: Bob King
*  Set the ISO to 800 for brighter auroras or 1600 for fainter ones and set the time to 30-seconds. If the aurora is bright and moving quickly, I’ll decrease exposure times to 10-15 seconds. The current crop of high end cameras now have the capacity to shoot at ISOs of 25,000. While those speeds may not give the smoothest images, dialing back to ISO 3200 and 6400 will make for photos that look like they were shot at ISO 400 on older generation cameras. A bright aurora at ISO 3200 can be captured in 5 seconds or less.

* Compose the scene in the viewfinder. If you’re lucky or plan well, you can include something interesting in the foreground like a building, a picturesque tree or lake reflection.

* OK, ready? Now press the button. When the image pops up on the viewing screen, does the image seem faint, too bright or just right. Make exposure adjustments as needed. If you need to expose beyond the typical maximum of 30 seconds, you can hold the shutter button down manually or purchase a cable release to hold it down for you.

It’s easy, right? Well then, why did it take me 400 words to explain it??? Have fun and good luck in your photography.

Tagged as:
aurora,
photography
Posted by Nelio Inacio at 6:08 AM 0 comments

Friday, September 12, 2014

Elemental Mystery: Lithium Is Also Rare Outside Of The Milky Way

Elemental Mystery: Lithium Is Also Rare Outside Of The Milky Way:



An image of globular cluster M54 taken by the Very Large Telescope Survey Telescope at the European Southern Observatory's Paranal Observatory in northern Chile. Credit: ESO

An image of globular cluster M54 taken by the Very Large Telescope Survey Telescope at the European Southern Observatory’s Paranal Observatory in northern Chile. Credit: ESO
This new picture of M54 — a part of a satellite galaxy to the Milky Way called the Sagittarius Dwarf Galaxy — is part of a “test case” astronomers have to figure out a mystery of missing lithium.

For decades, astronomers have been aware of a dearth of lithium in our own galaxy, the Milky Way. This image from the Very Large Telescope’s Survey Telescope represents the first effort to probe for the element outside of our galaxy.

“Most of the light chemical element lithium now present in the Universe was produced during the Big Bang, along with hydrogen and helium, but in much smaller quantities,” the European Southern Observatory stated.

“Astronomers can calculate quite accurately how much lithium they expect to find in the early Universe, and from this work out how much they should see in old stars. But the numbers don’t match — there is about three times less lithium in stars than expected. This mystery remains, despite several decades of work.”

In any case, observations of M54 show that the amount of lithium there is similar to the Milky Way — meaning that the lithium problem is not confined to our own galaxy. A paper based on the research was published in the Monthly Notices of the Royal Astronomical Society. The research was led by Alessio Mucciarelli at the University of Bologna in Italy.

Source: European Southern Observatory

Tagged as:
lithium,
m54,
messier 54,
sagitarrius dwarf galaxy,
very large telescope survey telescope
Posted by Nelio Inacio at 10:05 AM 0 comments

Aurora Watch! Two Solar Particle Blasts Could Start Smacking Into Earth Friday

Aurora Watch! Two Solar Particle Blasts Could Start Smacking Into Earth Friday:



A solar blast erupts in this picture captured by the Solar and Heliospheric Observatory on Sept. 10, 2014. Credit: ESA / NASA / SOHO

A solar blast erupts in this picture captured by the Solar and Heliospheric Observatory on Sept. 10, 2014. Credit: ESA / NASA / SOHO
Bim, bam, smash! The Sun hurled two clouds of particles in our general direction, putting space weather watchers on alert. There’s now a high chance of auroras on Sept. 12 (Friday), according to the National Oceanic and Atmospheric Administration, with more activity possible during the weekend.

The coronal mass ejections erupted Sept. 9 and Sept. 10 from sunspot AR2158. The Sept. 10 flare packed the strongest class punch the sun has, an X-flare, which briefly caused HF radio blackouts on Earth. We have some amateur shots of the sunspot and Sun below.

“Radio emissions from shock waves at the leading edge of the CME suggest that the cloud tore through the sun’s atmosphere at speeds as high as 3,750 km/s [2,330 miles per second],” wrote SpaceWeather.com. “That would make this a very fast moving storm, and likely to reach Earth before the weekend. Auroras are definitely in the offing.”

Photographer John Chumack captured the Sun and AR2158 in these pictures from Monday (Sept. 8). If you’ve got some great Sun shots to share, be sure to put it on our Universe Today Flickr group!

Sunspot AR2158 taken on Sept. 8, 2014. Credit: John Chumack

Sunspot AR2158 taken on Sept. 8, 2014. Credit: John Chumack
The Sun on Sept. 8, 2014, including active sunspots. Credit: John Chumack

The Sun on Sept. 8, 2014, including active sunspots. Credit: John Chumack
Tagged as:
ar2158,
sunspot,
X-class
Posted by Nelio Inacio at 10:04 AM 0 comments

A Lurking Companion Star Explains Enigmatic Supernova

A Lurking Companion Star Explains Enigmatic Supernova:



The above sequence depicts a rare supernova explosion. The topic panel

The above sequence depicts a rare supernova explosion. Hubble images (bottom panel) correspond to an artist’s conception (top panel). Credit: Kavli IPMU / NASA / Gastón Folatelli
Massive stars end their lives dramatically. Once the nuclear fuel deep within their cores is spent, there’s no longer any outward pressure to push against gravity, and the star collapses. But while the inner layers fall in to form a black hole or a neutron star, the outer layers fall faster, hitting the inner layers, and rebounding in a huge supernova explosion.

That’s the textbook definition. But some of these supernovae defy explanation. In 2011 one such explosion, dubbed SN 2011dh, pierced the Whirlpool galaxy, roughly 24 million-light years away. At the time astronomers were baffled. But now, thanks to NASA’s Hubble Space Telescope, they’ve discovered a companion star to this rare supernova and fit the final puzzle pieces together.

SN 2011dh is a Type IIb supernova, unusual in that it contains very little hydrogen and unexplainable via a textbook definition. Even so, astronomers can shed light on the progenitor star simply by digging through archived images from HST. Thanks to HST’s wealth of data and the fact that it observes the Whirlpool galaxy often, two independent research teams both detected a source — a yellow supergiant star — at the right location.

But astronomers don’t think yellow supergiant stars are capable of becoming supernovae … at least not in isolation.

At this point, controversy arose within the astronomical community. Several experts proposed that the observation was a false cosmic alignment and that the actual progenitor was an unseen massive star. Other experts proposed that the progenitor could have been the yellow supergiant, but that it must have belonged in a binary star system.

When a massive star in a binary system overflows its Roche lobe — the region outside that star where gravity dominates — it can pour material onto its smaller companion, therefore losing its hydrogen envelope and shrinking in mass.

At the time the mass-donor explodes, the companion star should be a massive blue star, having gained material during the mass transfer. Its high temperature should also cause it to emit mostly in the ultraviolet range, therefore rendering it invisible in any visible images.

So Gastón Folatelli from the Kavli Institute for the Physics and Mathematics of the Universe (IPMU) and colleagues decided to take a second look at the mysterious supernova in ultraviolet light. And their observations matched their expectations. The original supernova had faded, and a different point source had taken its place.

“One of the most exciting moments in my career as an astronomer was when I displayed the newly arrived HST images and saw the object right there, where we had anticipated it to be all along,” said Folatelli in a news release.

The research illustrates the intricate interplay between theory and observation. Astronomers often rely on theories long before they gain the technology necessary to provide the correct observations or spend years trying to explain odd observations with complex theoretical modeling. More often, however, the two coexist as theory and observation banter back and forth.

The findings have been published in the Astrophysical Journal Letters and are available online.

Tagged as:
Type II Supernovae,
yellow hypergiant
Posted by Nelio Inacio at 10:04 AM 0 comments

‘Venus Zone': The Anti-Habitable Area Around A Star That Can Breed Hell

‘Venus Zone': The Anti-Habitable Area Around A Star That Can Breed Hell:



A radar view of Venus taken by the Magellan spacecraft, with some gaps filled in by the Pioneer Venus orbiter. Credit: NASA/JPL

A radar view of Venus taken by the Magellan spacecraft, with some gaps filled in by the Pioneer Venus orbiter. Credit: NASA/JPL
Our hothouse planet of the solar system, Venus, is possibly a product of how close it is to the Sun, new research reveals. The team who have come up with a definition of a “Venus zone” around stars, saying that knowing where this area is could help pin down other areas that are more habitable for potential life.

“We believe the Earth and Venus had similar starts in terms of their atmospheric evolution,” stated lead author Stephen Kane, an astronomer at San Francisco State University. “Something changed at one point, and the obvious difference between the two is proximity to the Sun.”

The habitable region around a star is poorly understood because scientists don’t quite know what conditions are necessary for life. It usually refers to the area where liquid water is possible, although this also depends on the climate of the planet itself. Clouds, terrain and atmospheric composition are just some of the variables that could affect habitability.

Artist’s impression of a massive asteroid belt in orbit around a star. Credit: NASA-JPL / Caltech / T. Pyle (SSC)

Artist’s impression of a massive asteroid belt in orbit around a star. Credit: NASA-JPL / Caltech / T. Pyle (SSC)
To better figure out where potential Venus-like exoplanets lurk, Kane’s team used data from the planet-hunting Kepler Space Telescope and examined solar flux — or how much solar energy a planet gets — to figure out where the Venus zone would be. The zone is then defined between two regions: where a planet could have the “runaway greenhouse effect” seen on Venus, and the spot where the planet is so close to its star that energy would wear away its atmosphere.

The first step would be pinpointing which planets reside within these zones. In future decades, astronomers could then examine the planetary atmospheres with telescopes to learn more about how they are composed — and how similar they are to Earth or Venus. Meanwhile, Kane’s team plans to model if carbon in the planet’s atmosphere could affect the boundaries of the zone.

“If we find all of these planets in the Venus Zone have a runaway greenhouse-gas effect, then we know that the distance a planet is from its star is a major determining factor,” Kane stated. “That’s helpful to understanding the history between Venus and Earth.”

A preprint version of the paper is available on the Arxiv website. The research has been accepted for publication in Astrophysical Journal Letters.

Source: San Francisco State University

Tagged as:
venus zone
Posted by Nelio Inacio at 10:03 AM 0 comments

Astrophoto: The Sun as a Work of Art

Astrophoto: The Sun as a Work of Art:



A stylized Coronal Mass Ejection: The Sun as work of art. Credit and copyright: Rick Ellis.

A stylized Coronal Mass Ejection: The Sun as work of art. Credit and copyright: Rick Ellis.
Here’s yesterday’s solar flare as seen with a little flair added! Astrophotographer Rick Ellis from Toronto, Canada created this “artsy” Sun by using a series of photoshop filters and effects. He tinkered with the contrast at specific color ranges, applied “equalization,” and used a filter called “accented edges.”

“Then I posterized it and ran it through the “posterize edges” filter which really brings out many details,” Rick said via email.

Rick admitted to some confusion about the difference between solar flares and coronal mass ejections, and so we figured this might be a good time to explain. They do have several similarities, however: both solar flares and CMEs are energetic events on the Sun that are both associated with high energy particles, and they both depend on magnetic fields on the Sun.

In the case of a CME, coronal material is ejected into space at high speeds. According to Berkeley University the most obvious difference between a solar flare and a CME is the spatial scale on which they occur.

“Flares are local events as compared to CMEs which are much larger eruptions of the corona,” says the Berkeley webpage, and sometimes a CME can be larger than the Sun itself. Solar flares and coronal mass ejections often occur together, but each can also take place in the absence of the other.

Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.

Tagged as:
solar flare,
sun
Posted by Nelio Inacio at 10:03 AM 0 comments

Clear Skies Tonight? Go Out and See the Aurora

Clear Skies Tonight? Go Out and See the Aurora:



A low arc, glowing green from excited oxygen, spans the northern sky around 10:30 p.m Central Daylight Time from Duluth, Minn. The Big Dipper is off to the left. Credit: Bob King

A low arc, glowing green from excited oxygen, spans the northern sky around 9:30 p.m Central Daylight Time from Duluth, Minn. this evening September 11, 2014 at 9:30 p.m. CDTThe Big Dipper is off to the left. Credit: Bob King
Talk of aurora is in the air.  Our earlier story today by Elizabeth Howell alerted you to the possibility of northern lights. Well, it’s showtime!  As of 10:30 p.m. Eastern Daylight Time, the aurora has been active low in the northern sky.

Subtle pink rays stand above the green arc at 9:35 p.m. CDT. Credit: Bob King

Subtle pink rays stand above the green arc at 9:35 p.m. CDT. Credit: Bob King
From Duluth, Minn. U.S.,  a classic green arc low in the northern sky competed with the light of the rising gibbous moon. Once my eyes were dark-adapted, faint parallel rays stood streaked the sky above the arc. NOAA space weather forecasters expect this storm to peak between 1 a.m. CDT and sunrise Friday morning September 12 at a G2 or moderate level. Skywatchers across the northern tier of states and southern Canada should see activity across the northern sky. Moonlight will compromise the show to some degree

The approximate extent of the auroral oval forecast for 11:30 p.m. CDT from Ovation. Credit: NOAA

The approximate extent of the auroral oval forecast for 11:30 p.m. CDT from Ovation. Credit: NOAA
This is only the start. Things really kick into gear Friday night and Saturday morning with a G3 strong geomagnetic storm. Auroras might be visible as far south as Illinois and Kansas.

We’ll keep you in touch with the storm with regular updates over the next couple days. Here are some links to check during the night as you wait for the aurora to possibly put in an appearance at your house:

* Ovation oval – shows the approximate extent of the auroral oval that looks like a cap centered on Earth’s geomagnetic pole. During storms, the oval extends south into the northern U.S. and farther.

* Kp index – indicator of magnetic activity high overhead and updated every three hours. A Kp index of “5” means the onset of a minor storm; a Kp of “6”, a moderate storm.

* NOAA space weather forecast

* Advanced Composition Explorer (ACE) satellite plots – The magnetic field direction of the arriving wind from the sun. The topmost graph, plotting Bz, is your friend. When the curve drops into the negative zone that’s good! A prolonged stay at -10 or lower increases the chance of seeing the aurora.

Tagged as:
aurora,
flare,
northern lights,
oval
Posted by Nelio Inacio at 10:02 AM 0 comments

Lunar Love: Stunning Shots Abound In Phases Around The SuperMoon

Lunar Love: Stunning Shots Abound In Phases Around The SuperMoon:



The gibbous moon shines on Sept. 5, 2014. Credit: Christian Kamber

The gibbous moon shines on Sept. 5, 2014. Credit: Christian Kamber
While the SuperMoon of earlier this week got a lot of attention — and rightly so, given the Moon was closest in its orbit to Earth when it was full — the waning and waxing phases around our celestial neighbor are also beautiful. Haunting, in fact.

These shots were taken by members of our Universe Today Flickr pool, with the moon either entering or exiting the full moon phase. Got some stunning astronomy shots to share? Feel free to add your contributions to the group (which says you will give us permission to publish) and we may include them in a future story.

The moon in its waning gibbous phase on Sept. 12, 2014. Photo taken with a Canon 700D attached to a Maksutov 127mm telescope. Credit: Sarah&Simon Fisher

The moon in its waning gibbous phase on Sept. 12, 2014. Photo taken with a Canon 700D attached to a Maksutov 127mm telescope. Credit: Sarah&Simon Fisher
The moon shines red in this photo taken from Newcastle upon Tyne, England on Sept. 11, 2014. Credit: David Blanchflower

The moon shines red in this photo taken from Newcastle upon Tyne, England on Sept. 11, 2014. Credit: David Blanchflower
The large craters Atlas (left) and Hercules (below) on the moon. Taken using a Canon 1100D. Credit: Paul M. Hutchinson

The large craters Atlas (left) and Hercules (below) on the moon. Taken using a Canon 1100D. Credit: Paul M. Hutchinson
Tagged as:
astrophotography,
flickr,
Supermoon
Posted by Nelio Inacio at 10:02 AM 0 comments

Wow! Water Ice Clouds Suspected In Brown Dwarf Beyond The Solar System

Wow! Water Ice Clouds Suspected In Brown Dwarf Beyond The Solar System:



Artist's conception of brown dwarf WISE J085510.83-071442.5, which may host water ice clouds in its atmosphere. Credit: Rob Gizis (CUNY BMCC / YouTube (screenshot)

Artist’s conception of brown dwarf WISE J085510.83-071442.5, which may host water ice clouds in its atmosphere. Credit: Rob Gizis (CUNY BMCC / YouTube (screenshot)
What are planetary atmospheres made of? Figuring out the answer to that question is a big step on the road to learning about habitability, assuming that life tends to flourish in atmospheres like our own.

While there is a debate about how indicative the presence of, say, oxygen or water is of life on Earth-like planets, astronomers do agree more study is required to learn about the atmospheres of planets beyond our solar system.

Which is why this latest find is so exciting — one astronomy team says it may have spotted water ice clouds in a brown dwarf (an object between the size of a planet and a star) that is relatively close to our solar system. The find is tentative and also in an object that likely does not host life, but it’s hope that telescopes may get better at examining atmospheres in the future.

The object is called WISE J085510.83-071442.5, or W0855 for short. It’s the coldest brown dwarf ever detected, with an average temperature between 225 degrees Kelvin (-55 Fahrenheit, or -48 Celsius) and 265 Kelvin (17 Fahrenheit, or -8 Celsius.) It’s believed to be about three to 10 times the mass of Jupiter.

Astronomers looked at W0855 with an infrared mosaic imager on the 6.5-meter Magellan Baade telescope, which is located at Las Campanas Observatory in Chile. The team obtained 151 images across three nights in May 2014.



Astronomers plotted the brown dwarf on a color-magnitude chart, which is a variant of famous Hertzsprung-Russell diagram used to learn more about stars by comparing their absolute magnitude against their spectral types. “Color-Magnitude diagrams are a tool for investigating atmospheric properties of the brown dwarf population as well as testing model predictions,” the authors wrote in their paper.

Based on previous work on brown dwarf atmospheres, the team plotted W0855 and modelled it, discovering it fell into a range that made water ice clouds possible. It should be noted here that water ice is known to exist in all four gas giants of our own Solar System: Jupiter, Saturn, Uranus, and Neptune.

“Non-equilibrium chemistry or non-solar metallicity may change predictions,” the authors cautioned in their paper. “However, using currently available model approaches, this is the first candidate outside our own solar system to have direct evidence for water clouds.”

The research, led by the Carnegie Institution for Science’s Jacqueline Faherty, was published in Astrophysical Journal Letters. A preprint version of the paper is available on Arxiv.

Source: Carnegie Institution for Science

Tagged as:
brown dwarf,
W0855,
water ice,
WISE J085510.83-071442.5
Posted by Nelio Inacio at 10:01 AM 0 comments

An X-ray Tapestry

An X-ray Tapestry:

posted by chandra
on Wed, 2014-09-10 09:50


Puppis A

The destructive results of a powerful supernova explosion reveal themselves in a delicate tapestry of X-ray light, as seen in this image from NASA's Chandra X-Ray Observatory and the European Space Agency's XMM-Newton.

The image shows the remains of a supernova that would have been witnessed on Earth about 3,700 years ago. The remnant is called Puppis A, and is around 7,000 light years away and about 10 light years across. This image provides the most complete and detailed X-ray view of Puppis A ever obtained, made by combining a mosaic of different Chandra and XMM-Newton observations. Low-energy X-rays are shown in red, medium-energy X-rays are in green and high energy X-rays are colored blue.

More information at http://chandra.harvard.edu/photo/2014/puppisa/index.html

-Megan Watzke, CXC
Disclaimer: This service is provided as a free forum for registered users. Users' comments do not reflect the views of the Chandra X-ray Center and the Harvard-Smithsonian Center for Astrophysics.

Please note this is a moderated blog. No pornography, spam, profanity or discriminatory remarks are allowed. No personal attacks are allowed. Users should stay on topic to keep it relevant for the readers.

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Posted by Nelio Inacio at 9:30 AM 0 comments

NASA Launches New Era of Earth Science from Space Station

NASA Launches New Era of Earth Science from Space Station:

ISS International Space Station
Image Credit: NASA


September 08, 2014

The launch of a NASA ocean winds sensor to the International Space Station (ISS) this month inaugurates a new era of Earth observation that will leverage the space station's unique vantage point in space. Before the end of the decade, six NASA Earth science instruments will be mounted to the station to help scientists study our changing planet.

The first NASA Earth-observing instrument to be mounted on the exterior of the space station will launch from Cape Canaveral Air Force Station, Florida, on the next SpaceX Commercial Resupply Services flight, currently targeted for no earlier than Sept. 19. ISS-RapidScat will monitor ocean winds for climate research, weather predictions and hurricane monitoring from the space station.

The second instrument is the Cloud-Aerosol Transport System (CATS), a laser instrument that will measure clouds and the location and distribution of airborne particles such as pollution, mineral dust, smoke, and other particulates in the atmosphere. CATS will follow ISS-RapidScat on the fifth SpaceX space station resupply flight, targeted for December.

"We're seeing the space station come into its own as an Earth-observing platform," said Julie Robinson, chief scientist for the International Space Station Program at NASA's Johnson Space Center in Houston. "It has a different orbit than other Earth remote sensing platforms. It's closer to Earth, and it sees Earth at different times of day with a different schedule. That offers opportunities that complement other Earth-sensing instruments in orbit today."

The space station-based instruments join a fleet of 17 NASA Earth-observing missions currently providing data on the dynamic and complex Earth system. ISS-RapidScat and CATS follow the February launch of the Global Precipitation Measurement Core Observatory, a joint mission with the Japan Aerospace Exploration Agency, and the July launch of the Orbiting Carbon Observatory-2, making 2014 one of the busiest periods for new NASA Earth science missions in more than a decade.

Most of the agency's free-flying, Earth-observing satellites orbit the planet over the poles at altitudes higher than 400 miles in order to gather data from all parts of the planet. Although the space station does not pass over Earth's polar regions, its 240-mile-high orbit does offer logistical and scientific advantages.

"With the space station we don't have to build a spacecraft to gather new data -- it's already there," said Stephen Volz, associate director of flight programs in the Earth Science Division at NASA Headquarters in Washington. "The orbit enables rare, cross-disciplinary observations when the station flies under another sensor on a satellite. Designing instruments for the space station also gives us a chance to do high-risk, high-return instruments in a relatively economical way."

The data provided by ISS-RapidScat will support weather and marine forecasting, including tracking storms and hurricanes. The station's orbit will allow the instrument to make repeated, regular observations over the same locations at different times of day, providing the first near-global measurements of how winds change throughout the day. ISS-RapidScat was built by NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California.

CATS is a laser remote-sensing instrument, or lidar, that measures clouds and tiny aerosol particles in the atmosphere. These atmospheric components play a critical part in understanding how human activities such as pollution and fossil fuel burning contribute to climate change. CATS was built by NASA's Goddard Space Flight Center in Greenbelt, Maryland.

Two additional NASA Earth science instruments are scheduled to launch to the station in 2016. The Stratospheric Aerosol and Gas Experiment III (SAGE III), will measure aerosols, ozone, water vapor and other gases in the upper atmosphere to help scientists assess how the ozone layer is recovering and better understand global climate change. SAGE III was developed by NASA's Langley Research Center in Hampton, Virginia, and built by Ball Aerospace of Boulder, Colorado.

The Lightning Imaging Sensor (LIS) will detect and locate lightning over tropical and mid-latitude regions of the globe. The first LIS was launched in 1997 as part of NASA's Tropical Rainfall Measuring Mission. The sensor will monitor lightning for Earth science studies and provide cross-sensor calibration and validation with other space-borne instruments and ground-based lightning networks. LIS was developed by NASA's Marshall Space Flight Center in Huntsville, Alabama.

In July, NASA selected proposals for two new instruments that will observe changes in global vegetation from the space station, giving scientists new ways to observe how forests and ecosystems are affected by changes in climate and land use change. Both sensors will be completed before the end of the decade.

The Global Ecosystem Dynamics Investigation (GEDI) will use a laser-based system to study forest canopy structure in a range of ecosystems, from the tropics to the high northern latitudes. The observations will help scientists better understand the changes in carbon storage within forests from both human activities and natural climate variations. GEDI is managed by scientists at the University of Maryland, College Park.

The ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) is a high-resolution multiple wavelength thermal imaging spectrometer that will study water use and water stress in vegetation. Measurements of the loss of water from growing leaves and evaporation from the soil will help reveal how ecosystems change with climate and provide a critical link between the water cycle and plant health in both natural and agricultural ecosystems. ECOSTRESS is managed by JPL.

The space station provides several capabilities useful to both instruments. The space station orbit provides more observation time of forests and vegetation over temperate land masses than possible with the polar orbit commonly used for other types of Earth observations. The GEDI laser requires significant power resources, which the space station can provide.

For more information on Earth science activities aboard the space station, visit:

http://www.nasa.gov/issearthscience

NASA monitors Earth's vital signs from land, air and space with a fleet of satellites and ambitious airborne and ground-based observation campaigns. NASA develops new ways to observe and study Earth's interconnected natural systems with long-term data records and computer analysis tools to better see how our planet is changing. The agency shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.

For more information about NASA's Earth science activities in 2014, visit:

http://www.nasa.gov/earthrightnow

Steve Cole / Joshua Buck
NASA Headquarters, Washington

202-358-0918 / 202-358-1100

stephen.e.cole@nasa.gov / jbuck@nasa.gov


Alan Buis

Jet Propulsion Laboratory, Pasadena, Calif.

818-354-0474

alan.buis@jpl.nasa.gov

2014-301
Posted by Nelio Inacio at 9:29 AM 0 comments
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