Terry's Astronomy Thread.

[Bluearrowll]

Re: Terry's Astronomy Thread.

Daily Suspicious0bserver's Weather Post:
August 31, 2014

What's in the sky tonight?
August 31, 2014

-Spot the Moon at dusk with Saturn to its right and Mars to its lower left (for North America).

-As the stars come out this week, the first you see may be Arcturus shining high in the west. As the sky gets a little darker, look to its right for the Big Dipper scooping down in the northwest.

-As northern summer comes to a close, electrical storms are rumbling across the USA. After nightfall, red sprites can be seen dancing across the cloudtops. On Aug. 20th, Tom A. Warner photographed these speciments above New Underwood, South Dakota:



"On the night of Aug 20th, intense storms developed in north central South Dakota," says Warner. "Skies cleared out to the west and offered a chance to capture some sprites from the northern activity."

He saw not only sprites, but also green-glowing gravity waves. The waves are, literally, the ripple effect of a powerful thunderstorm on the mesosphere some 80 km above Earth's surface. From space, these waves look like a giant atmospheric bull's eye. From the ground, they appear to be green ripples in the sky, as shown in Warner's images.

Left to themselves, gravity waves would be invisible to the human eye. We see them, however, because they are colored green by an aurora-like phenomenon called "airglow." Airglow is caused by an assortment of chemical reactions in the upper atmosphere driven mainly by solar ultraviolet radiation. Gravity waves rippling away from the central axis of a thunderstorm cause temperature and density perturbations in the upper atmosphere. Speaking simplistically, those perturbations alter the chemical reaction rates of airglow, leading to more-bright or less-bright bands depending on whether the rates are boosted or diminished, respectively.

Inhabiting the upper reaches of Earth's atmosphere alongside meteors, noctilucent clouds and some auroras, sprites and mesospheric gravity waves are true space weather phenomena. Now is a good time to see them.

Astro Picture of the Day:
August 31, 2014

Source:
How was this picture taken? Usually, pictures of the shuttle, taken from space, are snapped from the space station. Commonly, pictures of the space station are snapped from the shuttle. How, then, can there be a picture of both the shuttle and the station together, taken from space? The answer is that during the Space Shuttle Endeavour's last trip to the International Space Station in 2011 May, a supply ship departed the station with astronauts that captured a series of rare views. The supply ship was the Russian Soyuz TMA-20 which landed in Kazakhstan later that day. The above spectacular image well captures the relative sizes of the station and docked shuttle. Far below, clouds of Earth are seen above a blue sea.

[Bluearrowll]

Re: Terry's Astronomy Thread.

Daily Suspicious0bserver's Weather Post:
September 1, 2014

What's in the sky tonight?
September 1, 2014

-First-quarter Moon this evening and Tuesday evening (exactly first quarter at 7:11 a.m. Eastern Daylight Time Tuesday morning). It's passing over Scorpius, as shown below.

-After a long, long summer day, Arctic skies are darkening again, and in the sunset observers are seeing rays of green in the twilight blue. Frank Olsen of Sortland, Norway, took this picture at sunset on Aug. 31st. "I went out last night to catch the sunset--but mostly the auroras," says Olsen. "Even before it was dark, the Northern Lights made an appearance."

More lights are in the offing. NOAA forecasters estimate a 20% of polar geomagnetic storms during the next 24 hours. The odds of Arctic auroras are higher, however, because it doesn't take a full-fledged storm to turn the twilight green at polar latitudes.

Astro Picture of the Day:
September 1, 2014

Source:
Why would the sky look like a giant target? Airglow. Following a giant thunderstorm over Bangladesh in late April, giant circular ripples of glowing air appeared over Tibet, China, as pictured above. The unusual pattern is created by atmospheric gravity waves, waves of alternating air pressure that can grow with height as the air thins, in this case about 90 kilometers up. Unlike auroras powered by collisions with energetic charged particles and seen at high latitudes, airglow is due to chemiluminescence, the production of light in a chemical reaction. More typically seen near the horizon, airglow keeps the night sky from ever being completely dark.

[Bluearrowll]

Re: Terry's Astronomy Thread.

Daily Suspicious0bserver's Weather Post:
September 2, 2014

What's in the sky tonight?
September 2, 2014

-The Great Square of Pegasus is well up in the east as soon as nightfall is complete. It's larger than your fist at arm's length and currently stands on one corner. Seen from your latitude at your time, how close is its balance to being perfect?

-A sunspot located just behind the sun's northeastern limb exploded yesterday, Sept. 1st @ 1105 UT, producing "a significant solar flare," according to NOAA analysts. NASA's STEREO-B spacecraft, stationed over the farside of the sun, recorded the extreme ultraviolet flash. A fast CME emerged from the blast site traveling approximately 2000 km/s (4.5 million mph). The flare also produced strong radio bursts and a farside solar proton storm. Only the intervening limb of the sun prevented Earth effects.

When flares occur on the Earthside of the sun, we classify them according to their X-ray intensity: C (weak), M (medium), or X (strong). Farside explosions, however, cannot be precisely classified because none of the spacecraft stationed over the farside of the sun are equipped with X-ray sensors. Based on the appearance of the flare at UV wavelengths, plus other factors such as the CME and radiation storm, we would guess that this was a strong-M or X-class event.

Soon, the source of the explosion will reveal itself as solar rotation carries it up and over the sun's NE limb. Earth-directed solar activity could be just a few days away.

Astro Picture of the Day:
September 2, 2014

Source:
How different are space and time at very small scales? To explore the unfamiliar domain of the miniscule Planck scale -- where normally unnoticeable quantum effects might become dominant -- a newly developed instrument called the Fermilab Holometer has begun operating at the Fermi National Accelerator Laboratory (Fermilab) near Chicago, Illinois, USA. The instrument seeks to determine if slight but simultaneous jiggles of a mirror in two directions expose a fundamental type of holographic noise that always exceeds a minimum amount. Pictured above is one of the end mirrors of a Holometer prototype. Although the discovery of holographic noise would surely be groundbreaking, the dependence of such noise on a specific laboratory length scale would surprise some spacetime enthusiasts. One reason for this is the Lorentz Invariance postulate of Einstein's special relativity, which states that all length scales should appear contracted to a relatively moving observer -- even the diminutive Planck length. Still, the experiment is unique and many are curious what the results will show.

[Bluearrowll]

Re: Terry's Astronomy Thread.

Daily Suspicious0bserver's Weather Post:
September 3, 2014

What's in the sky tonight?
September 3, 2014

-For days, amateur astronomers around the world have been monitoring an enormous filament of dark plasma snaking across the face of the sun. Yesterday it erupted. A movie from NASA's Solar Dynamics Observatory seems to show debris from the blast hurtling in the general direction of Earth. Stay tuned for coronagraph data, which could confirm or refute an Earth-directed CME.

Astro Picture of the Day:
September 3, 2014

Source:
To some, the outline of the open cluster of stars M6 resembles a butterfly. M6, also known as NGC 6405, spans about 20 light-years and lies about 2,000 light years distant. M6, pictured above, can best be seen in a dark sky with binoculars towards the constellation of the Scorpion (Scorpius), coving about as much of the sky as the full moon. Like other open clusters, M6 is composed predominantly of young blue stars, although the brightest star is nearly orange. M6 is estimated to be about 100 million years old. Determining the distance to clusters like M6 helps astronomers calibrate the distance scale of the universe.

[Bluearrowll]

Re: Terry's Astronomy Thread.

Daily Suspicious0bserver's Weather Post:
September 4, 2014

What's in the sky tonight?
September 4, 2014

-In Friday's dawn, use binoculars to help pick up Venus just above the eastern horizon about 30 minutes before sunrise. It's far to the lower left of Jupiter. Can you make out Regulus, less than a hundredth as bright, within 1° of Venus?

-On Sept. 2nd, an enormous filament of dark plasma, which had been snaking across the face of the sun for days, became unstable and erupted. NASA's Solar Dynamics Observatory recorded the event (movies: #1, #2). A CME emerging from the blast site appears to have an Earth-directed component.

According to NOAA analysts, the CME could deliver a glancing blow to Earth's magnetic field on Sept. 6th. This is not a particularly fast or powerful CME. Nevertheless, the coming impact could spark auroras. The last two minor CMEs that struck Earth in late August triggered beautiful displays of Northern and Southern Lights. The reason: it's aurora season. High-latitude sky watchers should prepare for Sept. 6th.

Astro Picture of the Day:
September 4, 2014

Source:
On October 19th, a good place to watch Comet Siding Spring will be from Mars. Then, this inbound visitor (C/2013 A1) to the inner solar system, discovered in January 2013 by Robert McNaught at Australia's Siding Spring Observatory, will pass within 132,000 kilometers of the Red Planet. That's a near miss, equivalent to just over 1/3 the Earth-Moon distance. Great views of the comet for denizens of planet Earth's southern hemisphere are possible now, though. This telescopic snapshot from August 29 captured the comet's whitish coma and arcing dust tail sweeping through southern skies. The fabulous field of view includes, the Small Magellanic Cloud and globular star clusters 47 Tucanae (right) and NGC 362 (upper left). Worried about all those spacecraft in Martian orbit? Streaking dust particles from the comet could pose a danger and controllers plan to position Mars orbiters on the opposite side of the planet during the comet's close flyby.

[Bluearrowll]

Re: Terry's Astronomy Thread.

Daily Suspicious0bserver's Weather Post:
September 5, 2014

What's in the sky tonight?
September 5, 2014

-Saturn, Mars, Delta (δ) Scorpii, and Antares form an equally-spaced ragged line in the southwest at dusk, as shown at right. Delta Scorpii used to be a bit dimmer than Beta above it. Then in July 2000 it doubled in brightness. It has remained bright, with slow fluctuations, ever since.
Look high above the Moon this evening for Altair.

-This Sunday, a house-sized asteroid named "2014 RC" will fly through the Earth-Moon system almost inside the orbit of geosynchronous satellites. At closest approach, Sept. 7th at 18:18 UTC, the 20-meter-wide space rock will pass just 40,000 km over New Zealand. This diagram from NASA shows the geometry of the encounter.

There is no danger of a collision with Earth.

Asteroid 2014 RC was discovered on the night of August 31 by the Catalina Sky Survey near Tucson, Arizona, and independently detected the next night by the Pan-STARRS 1 telescope, located on the summit of Haleakalā on Maui, Hawaii. Follow-up observations quickly confirmed the orbit of 2014 RC: it comes from just beyond the orbit of Mars.

The close appproach of this space rock offers researchers an opportunity for point-blank studies of a near-Earth asteroid. Even amateur astronomers will be able to track it. Around the time of closest approach, it will brighten to magnitude +11.5 as it zips through the constellation Pisces. This means it will be invisible to the naked eye but a relatively easy target for backyard telescopes equipped with CCD cameras.

According to NASA, "[the orbit of 2014 RC] will bring it back to our planet's neighborhood in the future. The asteroid's future motion will be closely monitored, but no future threatening Earth encounters have been identified."

If you want to try and see this asteroid for yourself, use the following link for tracking information: http://www.minorplanetcenter.net/db_...RC&commit=Show

Astro Picture of the Day:
September 5, 2014

Source:
This rich starscape spans nearly 7 degrees on the sky, toward the Sagittarius spiral arm and the center of our Milky Way galaxy. A telescopic mosaic, it features well-known bright nebulae and star clusters cataloged by 18th century cosmic tourist Charles Messier. Still popular stops for skygazers M16, the Eagle (far right), and M17, the Swan (near center) nebulae are the brightest star-forming emission regions. With wingspans of 100 light-years or so, they shine with the telltale reddish glow of hydrogen atoms from over 5,000 light-years away. Colorful open star cluster M25 near the upper left edge of the scene is closer, a mere 2,000 light-years distant and about 20 light-years across. M24, also known as the Sagittarius Star Cloud, crowds in just left of center along the bottom of the frame, fainter and more distant Milky Way stars seen through a narrow window in obscuring fields of interstellar dust.

[Bluearrowll]

Re: Terry's Astronomy Thread.

Daily Suspicious0bserver's Weather Post:
September 6, 2014

What's in the sky tonight?
September 6, 2014

-This is International Observe the Moon night! Zoom in on the map

http://observethemoonnight.org/

to find an event near you. Or set up your own telescope for the public, and add your event to the map so people can find you! The Moon is waxing gibbous, two days from full. (Just make sure it'll be in view from your site when you tell people to come!)

Also, look to the right of the Moon, by a little more than a fist-width at arm's length, for two faintish (3rd-magnitude) stars: Alpha and Beta Capricorni, one above the other. Alpha is the one on top. With sharp vision, you can barely see that it's double. Binoculars resolve it easily.

-NOAA forecasters estimate a 25% chance of polar geomagnetic storms on Sept. 6th when a CME is expected to deliver a glancing blow to Earth's magnetic field. High-latitude sky watchers should be alert for auroras.

Astro Picture of the Day:
September 6, 2014

Source:
Like a rainbow at night, a beautiful moonbow shines above the western horizon in this deserted beach scene from Molokai Island, Hawaii, USA, planet Earth. Captured last June 17 in early morning hours, the lights along the horizon are from Honolulu and cities on the island of Oahu some 30 miles away. So where was the Moon? A rainbow is produced by sunlight internally reflected in rain drops from the direction opposite the Sun back toward the observer. As the light passes from air to water and back to air again, longer wavelengths are refracted (bent) less than shorter ones resulting in the separation of colors. And so the moonbow is produced as raindrops reflect moonlight from the direction opposite the Moon. That puts the Moon directly behind the photographer, still low and rising over the eastern horizon, a few days past its full phase.

[Bluearrowll]

Re: Terry's Astronomy Thread.

Daily Suspicious0bserver's Weather Post:
September 7, 2014

What's in the sky tonight?
September 7, 2014

-Look for bright Vega passing your zenith in late twilight, if you live in the world's mid-northern latitudes. Vega goes right through your zenith if you're at latitude 39° north (near Baltimore, Kansas City, Lake Tahoe, Sendai, Beijing, Athens, Lisbon). How closely can you judge this?

-According to NOAA analysts, a CME hit Earth's magnetic field on Sept. 6th at 1525 UT. However, the impact was weak and did not spark geomagnetic storms.

Astro Picture of the Day:
September 7, 2014

http://vimeo.com/58385453

Source:
Have you ever watched the Moon rise? The slow rise of a nearly full moon over a clear horizon can be an impressive sight. One impressive moonrise was imaged in early 2013 over Mount Victoria Lookout in Wellington, New Zealand. With detailed planning, an industrious astrophotographer placed a camera about two kilometers away and pointed it across the lookout to where the Moon would surely soon be making its nightly debut. The above single shot sequence is unedited and shown in real time -- it is not a time lapse. People on Mount Victoria Lookout can be seen in silhouette themselves admiring the dawn of Earth's largest satellite. Seeing a moonrise yourself is not difficult: it happens every day, although only half the time at night. Each day the Moon rises about fifty minutes later than the previous day, with a full moon always rising at sunset. A good time to see a moonrise will occur at sunset on Tuesday as the Moon's relative closeness to Earth during a full phase -- called a supermoon -- will cause it to appear slightly larger and brighter than usual.

[Bluearrowll]

Re: Terry's Astronomy Thread.

Daily Suspicious0bserver's Weather Post:
September 8, 2014

What's in the sky tonight?
September 8, 2014

-NOAA forecasters have raised the odds of an X-class solar flare today to 30%. Two sunspots turning toward Earth pose a threat for such eruptions: AR2157 and AR2158. Both are capable of strong geoeffective activity.

-On Sunday, Sept. 7th, house-sized asteroid 2014 RC flew past Earth. There was no danger of a collision, but the space rock was close. It sailed just underneath Earth's belt of geeosynchronous satellites and about 40,000 km over New Zealand. Using robotic telescope in Australia, a team of astronomers led by Ernesto Guido photographed 2014 RC zipping through the southern constellation Phoenix at 10 km/s (22,000 mph).

2014 RC came from the asteroid belt just beyond the orbit of Mars. According to NASA, "2014 RC will return to our planet's neighborhood in the future. The asteroid's future motion will be closely monitored, but no future threatening Earth encounters have been identified."

Astro Picture of the Day:
September 8, 2014

Source:
What is so super about tomorrow's supermoon? Tomorrow, a full moon will occur that appears slightly larger and brighter than usual. The reason is that the Moon's fully illuminated phase occurs within a short time from perigee - when the Moon is its closest to the Earth in its elliptical orbit. Although the precise conditions that define a supermoon vary, given one definition, tomorrow's will be the third supermoon of the year -- and the third consecutive month that a supermoon occurs. One reason supermoons are popular is because they are so easy to see -- just go outside and sunset and watch an impressive full moon rise! Since perigee actually occurs today, tonight's sunset moonrise should also be impressive. Pictured above, a supermoon from 2012 is compared to a micromoon -- when a full Moon occurs near the furthest part of the Moon's orbit -- so that it appears smaller and dimmer than usual. Given many definitions, at least one supermoon occurs each year, with the next being 2015 August 30.

[Bluearrowll]

Re: Terry's Astronomy Thread.

Daily Suspicious0bserver's Weather Post:
September 9, 2014

What's in the sky tonight?
September 9, 2014

-Arcturus is the bright star fairly high due west at nightfall. It's an orange giant 37 light-years away. Off to its right in the northwest is the Big Dipper, most of whose stars are about 80 light-years away.

-Reports are circulating of a meteorite strike in Nicaragua on Sunday, Sept. 7th. Because the timing coincides with the flyby of asteroid 2014 RC, some reporters have suggested a link. We are skeptical. The crater outside Managua looks more like it was dug by a backhoe than excavated by a high-energy meteoritic explosion. Also, no streak of light corresponding to a meteor was actually observed. Stay tuned for updates on this developing story. http://www.bbc.com/news/world-latin-america-29106843

-The northern autumnal equinox is less than two weeks away. That makes tonight's full Moon the Harvest Moon, the full Moon closest to the beginning of Fall. Ruslan Merzlyakov sends this picture of the pumpkin-colored orb from Nykøbing Mors, Denmark:

"It was a very beautiful moonrise!" he says.

The name "Harvest Moon" harkens back to a bygone era. Before the days of electric lights, farmers relied on moonlight to harvest crops which ripened all at once in autumn. They couldn't afford to stop working at sunset, so "harvest moonlight" was essential to their operations. The flow of electricity has made the Moon obsolete as a source of practical illumination, but not as an object of beauty. Step outside tonight at sunset, look east and enjoy the view.

Astro Picture of the Day:
September 9, 2014

Source:
This sky looked delicious. Double auroral ovals were captured above the town lights of Östersund, Sweden, last week. Pictured above, the green ovals occurred lower to the ground than violet aurora rays above, making the whole display look a bit like a cupcake. To top it off, far in the distance, the central band or our Milky Way Galaxy slants down from the upper left. The auroras were caused by our Sun ejecting plasma clouds into the Solar System just a few days before, ionized particles that subsequently impacted the magnetosphere of the Earth. Aurora displays may continue this week as an active sunspot group rotated into view just a few days ago.

[Bluearrowll]

Re: Terry's Astronomy Thread.

Daily Suspicious0bserver's Weather Post:
September 10, 2014

What's in the sky tonight?
September 10, 2014

-The gibbous Moon, still big, rises in the east in late twilight. Look well above it for the bottom corner of the up-tilted Great Square of Pegasus.

-NOAA forecasters have issued a geomagnetic storm warning for Sept. 12th when a CME (described below) is expected to deliver a glancing but potent blow to Earth's magnetic field. The storm could reach moderate intensity (G2-class) with auroras visible across northern-tier US states such as Maine, Michigan, and Minnnesota.

-Yesterday, the magnetic canopy of sunspot AR2158 erupted, producing an explosion that lasted more than 6 hours. The flare peaked on Sept. 9th at 00:30 UT with a classification of M4 on the Richter Scale of Solar Flares. Long-duration flares tend to produce bright CMEs, and this one was no exception. Coronagraphs onboard the Solar and Heliospheric Observatory observed a CME racing out of the blast site at nearly 1,000 km/s (2.2 million mph).

Most of the storm cloud is heading north of the sun-Earth line, but not all. A fraction of the CME will deliver a glancing blow to Earth's magnetic field during the early hours of Sept. 12th. In the past few weeks, glancing blows from minor CMEs have sparked beautiful auroras around the Arctic Circle. This CME could spark even better displays. NOAA forecasters estimate a 79% (not a typo: 79%) chance of polar geomagnetic storming on Sept. 12th.

Astro Picture of the Day:
September 10, 2014

Source:
It is not only one of the largest structures known -- it is our home. The just-identified Laniakea Supercluster of galaxies contains thousands of galaxies that includes our Milky Way Galaxy, the Local Group of galaxies, and the entire nearby Virgo Cluster of Galaxies. The colossal supercluster is shown in the above computer-generated visualization, where green areas are rich with white-dot galaxies and white lines indicate motion towards the supercluster center. An outline of Laniakea is given in orange, while the blue dot shows our location. Outside the orange line, galaxies flow into other galatic concentrations. The Laniakea Supercluster spans about 500 million light years and contains about 100,000 times the mass of our Milky Way Galaxy. The discoverers of Laniakea gave it a name that means "immense heaven" in Hawaiian.

[Bluearrowll]

Re: Terry's Astronomy Thread.

Daily Suspicious0bserver's Weather Post:
September 11, 2014

What's in the sky tonight?
September 11, 2014

-A pair of CMEs is heading for Earth. The two solar storm clouds were launched on Sept. 9th and 10th by strong explosions in the magnetic canopy of sunspot AR2158. NOAA forecasters estimate a nearly 80% chance of polar geomagnetic storms on Sept. 12th when the first of the two CMEs arrives. Auroras are in the offing, possibly visible at mid-latitudes before the weekend.

-Sunspot AR2158 erupted on Sept. 10th at 17:46 UT, producing an X1.6-class solar flare. A flash of ultraviolet radiation from the explosion ionized the upper layers of Earth's atmosphere, disturbing HF radio communications for more than an hour. More importantly, the explosion hurled a CME directly toward Earth. The Solar and Heliospheric Observatory photographed the expanding cloud.

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 3750 km/s. That would make this a very fast moving storm, and likely to reach Earth before the weekend. Auroras are definitely in the offing.

-The X-flare of Sept 10th caused a radio blackout on Earth. Ironically, it also caused a blast of radio noise. Radio astronomers and hams in the Americas and across the Pacific Ocean heard static roaring from the loudspeakers of their shortwave receivers. "It was absolutely howling," reports Thomas Ashcraft, who sends this 3-minute recording from his amateur radio observatory in rural New Mexico.

"This is what I heard at the onset of the flare," he explains. "By the time the flare peaked, it became almost too intense for my ears."

Advice: Listen to the sound file using stereo headphones. The two channels correspond to two radio frequencies--22 and 23 MHz. Link: http://www.spaceweather.com/images20...shcraft_02.mp3

Radio emissions like these are caused by shock waves in the sun's atmosphere. Looking at the CME pictured in the news item above, it is easy to imagine how the fast-moving cloud would spawn shock waves in the atmosphere overlying sunspot AR2158. Those shock waves triggered plasma instabilities which, in turn, generated the shortwave radio emissions.

More radio bursts may be in the offing. Sunspots AR2157 and AR2158 have unstable magnetic fields that harboor energy for strong explosions. NOAA forecasters estimate a 40% chance of X-class flares and a whopping 85% chance of M-flares on Sept. 11th.

Astro Picture of the Day:
September 11, 2014

Source:
You might not guess it, but sunrise was still hours away when this nightscape was taken, a view along the eastern horizon from a remote location in Chile's Atacama desert. Stretching high into the otherwise dark, starry sky the unusually bright conical glow is sunlight though, scattered by dust along the solar system's ecliptic plane . Known as Zodiacal light, the apparition is also nicknamed the "false dawn". Near center, bright star Aldebaran and the Pleiades star cluster seem immersed in the Zodiacal light, with Orion toward the right edge of the frame. Reddish emission from NGC 1499, the California Nebula, can also be seen through the tinge of airglow along the horizon.

[Bluearrowll]

Re: Terry's Astronomy Thread.

Daily Suspicious0bserver's Weather Post:
September 12, 2014

What's in the sky tonight?
September 12, 2014

-The first of two CMEs expected to hit Earth's magnetic field on Sept. 12th has arrived, and a minor (G1-class) geomagnetic storm is underway as a result of the impact. The second and potentially more powerful CME is still en route. NOAA forecasters say geomagnetic storming could become strong (G3-class) during the late hours of Sept. 12th and Sept 13th after the second CME arrives.

-Observers in Canada and several northern-tier US states saw mild green auroras after the first impact. Matthew Moses sends this picture from Munger, MN. "It was a somewhat subdued display," says Moses. "I am looking forward to see what the next CME treats us to."

The next CME, now only hours away, was launched by an X-class flare, so it is potent. However, not every potent CME produces a potent geomagnetic storm. It all depends on the inner magnetic architecture of the CME, which is unknown until the CME actually arrives. NOAA forecasters are estimating a 45% chance that strong magnetic disturbances will reach mid-latitudes on Sept 13--almost like a coin toss.

Sky watchers should remain alert for auroras.

Astro Picture of the Day:
September 12, 2014

Source:
Driven by the explosion of a massive star, supernova remnant Puppis A is blasting into the surrounding interstellar medium about 7,000 light-years away. At that distance, this remarkable false-color exploration of its complex expansion is about 180 light-years wide. It is based on the most complete X-ray data set so far from the Chandra and XMM/Newton observations, and infrared data from the Spitzer Space Telescope. In blue hues, the filamentary X-ray glow is from gas heated by the supernova's shock wave, while the infrared emission shown in red and green is from warm dust. The bright pastel tones trace the regions where shocked gas and warmed dust mingle. Light from the initial supernova itself, triggered by the collapse of the massive star's core, would have reached Earth about 3,700 years ago, though the Puppis A supernova remnant remains a strong source in the X-ray sky.

[Bluearrowll]

Re: Terry's Astronomy Thread.

Daily Suspicious0bserver's Weather Post:
September 13, 2014

What's in the sky tonight?
September 13, 2014

-As predicted, a pair of CMEs hit Earth's magnetic field in quick succession on Sept. 11th and 12th. The result was a G3-class geomagnetic storm, the most intense of the year so far. At the peak of the storm on Sept 12-13, bright auroras ringed the Arctic Circle and spilled down over several northern-tier US states. The sky over Maine exploded in a rainbow of colors. "I took the picture from Casco, Maine, facing north towards the Presidential Range in New Hampshire," says photographer John Stetson. "Red, purple, green, blue--all the colors were there!"

The storm is subsiding now. Nevertheless, high-latitude sky watchers should remain alert for auroras. NOAA forecasters estimate a whopping 90% chance of additional polar geomagetic activity on Sept. 13th as Earth passes through the wake of the double CME.

Sky watchers should remain alert for auroras.

-On Sept. 12th, Spaceweather.com was offline for more than 12 hours during the most intense geomagnetic storm of the year. Ironically, the outage was not caused by solar activity. A hardware failure in the network of our Internet service provider brought the web site down at the worst possible time. Webmaster Dr. Tony Phillips apologizes to our readers, alert subscribers, and advertisers for the outage. We are taking steps to make sure this cannot happen again.

Astro Picture of the Day:
September 13, 2014

Source:
Now, as you sip your cosmic latte you can view 100 Hubble Space Telescope images at the same time. The popular scenes of the cosmos as captured from low Earth orbit are all combined into this single digital presentation. To make it, Hubble's top 100 images were downloaded and resized to identical pixel dimensions. At each point the 100 pixel values were arranged from lowest to highest, and the middle or median value was chosen for the final image. The combined image results in a visual abstraction - light from across the Universe surrounded by darkness. Hubble's Top 100 images: http://www.spacetelescope.org/images/archive/top100/

[Bluearrowll]

Re: Terry's Astronomy Thread.

Daily Suspicious0bserver's Weather Post:
September 14, 2014

What's in the sky tonight?
September 14, 2014

-Sunspot AR2158, the source of last week's powerful X-flare, is decaying as it turns away from Earth. This is decreasing the chance of another geoeffective explosion. NOAA forecasters put the odds of an X-flare today at a waning 25%.

-While the web site Spaceweather.com was down during the most intense geomagnetic storm of the year, the webmaster shook off the stress by going outside ... and launching a space weather probe. Carried aloft by a helium balloon, the probe was prepared and released by the students of Earth to Sky Calculus just as the planetary K-index hit 7during the waning hours of Sept. 12th.

Inside the balloon's payload, there was a high-energy radiation sensor, a cryogenic thermometer, multiple GPS altimeters and trackers, and three cameras to record the flight. The launch was the latest in an ongoing series of suborbital balloon flights to measure the effect of stormy space weather on Earth's atmosphere from ground level to the stratosphere. Soon, the group will release an entire year's worth of data of interest to commercial aviation and space tourism.

After a 2.5 hour flight, the payload has parachuted back to Earth and landed in the Inyo Mountains of central California. A student team will recover the payload and its sensors this weekend.

Astro Picture of the Day:
September 14, 2014

Source:
The first hint of what will become of our Sun was discovered inadvertently in 1764. At that time, Charles Messier was compiling a list of diffuse objects not to be confused with comets. The 27th object on Messier's list, now known as M27 or the Dumbbell Nebula, is a planetary nebula, the type of nebula our Sun will produce when nuclear fusion stops in its core. M27 is one of the brightest planetary nebulae on the sky, and can be seen toward the constellation of the Fox (Vulpecula) with binoculars. It takes light about 1000 years to reach us from M27, shown above in colors emitted by hydrogen and oxygen. Understanding the physics and significance of M27 was well beyond 18th century science. Even today, many things remain mysterious about bipolar planetary nebula like M27, including the physical mechanism that expels a low-mass star's gaseous outer-envelope, leaving an X-ray hot white dwarf.