To illustrate the growing spottiness of the sun, each active region in this Jan. 5th image from NASA's Solar Dynamics Observatory (SDO) is circled:
The most active sunspot so far is emerging over the sun's northeastern limb. On Jan. 5th at 09:34 UT, the unnumbered region unleashed an M1.7-class eruption that sent a wave of ionization rippling through the upper atmosphere over Europe. The flare was too brief, however, to produce a significant CME. SDO recorded a movie of the explosion's extreme ultraviolet flash:
More flares appear to be in the offing; stay tuned.
Realtime Space Weather Photo Gallery
TWO METEOR SHOWERS IN PROGRESS: The annual Quadrantid meteor shower, caused by debris from shattered comet 2003 EH1, peaked on Jan. 3rd and should be finished--but maybe not. "The Canadian Meteor Orbit Radar (CMOR) is still seeing strong Quadrantid activity," reports Prof. Peter Brown of the University of Western Ontario. "The overnight results have just been processed, and here is a skychart plot showing radiant activity as it appeared around 5 am EST on the morning of Jan. 4th."
"Notice also the relatively strong shower coming right out of the head of Leo," points out Brown. "This is the fast (54 km/s) January Leonids (JLE), first detected a few years ago by CMOR, but usually overlooked as it peaks the same day as the Quadrantids."
"The January Leonid shower is unusual in that it is quite strong (10 meteors per hour) and has an orbit which gets very close to the Sun (perihelion about 0.05 AU). In fact, it has the smallest perihelion of any major shower detected by CMOR. It also has a nearly unbound orbit and is almost certainly associated with an as yet unidentified sungrazing comet. Very little is known about the stream - optical observations would be most helpful, particularly to define the orbit at larger meteoroid sizes. The shower remains active as seen by CMOR until Jan 7."
There are so many spots on the sun, even a jumbo jet cannot hide them:
Raffaello Lena took the picture on January 5 not far from the international airport in Rome, Italy. "An animation of the flyby is available here," he says.
AURORA WATCH: "With solar activity being so low lately, you wouldn't expect many auroras. Yet here in Inari, Finland," reports Andy Keen, "we've had some wonderfully clear skies and excellent displays." He photographed this scene on Jan. 5th:
"The auroras became visible at approximately 16:00 hrs and lasted until midnight," he says.
More lights are in the offing. A solar wind stream is heading for Earth and it could spark polar auroras when it arrives on Jan. 8-9. NOAA forecasters estimate a 15% - 20% chance of geomagnetic storms.
Of greater interest, perhaps, is the large sunspot emerging just south of AR1652. Denoted by an arrow, the unnumbered region is crackling with C-class solar flares and, based on its size, could be capable of even stronger eruptions. We will know more in the days ahead as the sunspot turns toward Earth; a more direct view will reveal what kind of magnetic field the sunspot posseses. Solar flare alerts: text, voice.
AURORA WATCH: Mild but effective gusts of solar wind are buffeting Earth's magnetic field, sparking auroras around the Arctic Circle. Last night in Abisko National Park, Sweden, aurora tour guide Chad Blakley received a grand display for his clients:
"Tonight was the first night of our January Aurora Photo Expedition and I am happy to report that all eight of our guests were able to see and photograph a very nice aurora display in the skies above Abisko National park," says Blakeley. "The lights started around 7:00 PM and continued to dance in the sky until we were all too tired to carry on. We are hopeful that the next few days will continue to impress!"
He could get his wish. A minor stream of solar wind flowing from a hole in the sun's corona is due to hit Earth's magnetic field on Jan. 9-10, producing a display to keep the tour guides busy. Aurora alerts: text, voice.
BIG SUNSPOT: A very large sunspot is emerging over the sun's eastern limb. Numbered AR1654, it consists of two dark cores each 4 or more times wider than Earth. NASA's Solar Dynamics Observatory took this picture during the early hours of Jan. 9th:
So far the sunspot is relatively quiet, producing only a smattering of low-level C-class solar flares. We will know more about AR1654's flare-producing potential in the days ahead as the sunspot turns toward Earth. A direct view will reveal what kind of magnetic field the sunspot posseses, which is a key requirement for flare forecasting. For now, NOAA forecasters are estimating a 35% chance of M-class flares and a 5% chance of X-flares during the next 24 hours. Solar flare alerts: text, voice.
EVIL TWINS? A pair of large sunspots has rotated into view over the sun's eastern limb. The two dark cores, collectively known as AR1654, are each big enough to swallow Earth four times over. NASA's Solar Dynamics Observatory took this picture of the twins during the early hours of Jan. 10th:
The two sunspots are connected by a canopy of strong magnetic fields, which are presently crackling with low-level C-flares. Much stronger eruptions are possible. NOAA forecasters estimate a 40% chance of M-class flares and a 5% chance of X-flares during the next 24 hours. Solar flare alerts: text, voice.
ACTIVE SUNSPOT: Big sunspot AR1654 is crackling with C- and M-class solar flares, and it poses a threat for even stronger eruptions. NOAA forecasters estimate a 10% chance of X-flares today. Solar flare alerts: text, voice.
Flares are illuminating the sunspot's magnetic canopy like flash bulbs at a rock concert; the phenomenon is evident in this 37-hour extreme ultraviolet movie from NASA's Solar Dynamics Observatory:
Since it first appeared four days ago, sunspot AR1654 has been facing away from Earth. But now it is turning toward us, increasing the "geo-effectiveness" of its explosions. This could be the sunspot that breaks the recent lengthy spell of calm space weather around our planet.
Amateur astronomers with backyard solar telescopes are encouraged to monitor in the days ahead. It is not only crackling, but also growing. As of Jan 12th, the behemoth stretches more than 180,000 km (14 Earth diameters) from end to end. Dennis Simmons sends this picture of the behemoth from Brisbane, Australia:
"Although the air was milky from nearby bush fires burning north of Brisbane, the seeing turned out to be good enough for a high-resolution shot," says Simmons. "I dedicate this image to the brave Australian fire fighters, working in horrendous, hot and windy conditions whilst fighting fires burning out of control across the south-east states of our country. I salute your selfless courage."
COMET ISON APPROACHES: Later this year, Comet ISON could put on an unforgettable display as it plunges toward the sun for a fiery encounter likely to turn the "dirty snowball" into a naked-eye object in broad daylight. At the moment, however, it doesn't look like much. John Chumack sends this picture, taken Jan. 8th, from his private observatory in Yellow Springs, Ohio:
"Comet ISON (C/2012 S1) is currently in the constellation Gemini, moving between the heads of the twins Castor and Pollux," says Chumack. "It is still pretty faint, near 16th magnitude, but don't be fooled by that. This could become one of the best comets in many years."
Comet ISON is a sungrazer. On Nov. 28, 2013, it will fly through the sun's outer atmosphere only 1.2 million km from the stellar surface below. If the comet survives the encounter, it could emerge glowing as brightly as the Moon, visible near the sun in the blue daylight sky. The comet's dusty tail stretching into the night would create a worldwide sensation.
Comet ISON looks so puny now because it is so far away, currently near the orbit of Jupiter. As it falls toward the sun in the months ahead it will warm up and reveal more about its true character. By the summer of 2013, researchers should know whether optimistic predictions about Comet ISON are justified. Possibilities range from "Comet of the Century" to disintegrated dud. Stay tuned!
ARCTIC AURORAS: A stream of solar wind is blowing around Earth and buffeting our planet's magnetic field. Although the pressure of the wind has not been strong enough to trigger a full-fledged geomagnetic storm, auroras are nevertheless dancing around the Arctic Circle. Peter Rosén sends this picture from Kiruna in the Swedish Lapland:
"Blue jeans, 1 meter of soft snow, and a temperature of -15 degrees is usually not a good combination," says Rosen. "But who cares when the aurora dances above your head like they did last night (Jan. 13th). The lights kept me warm the entire night. It was the most powerfull aurora so far for me this winter."
More auroras are in the offing. NOAA forecasters estimate a 15% chance of polar geomagnetic activity as the solar wind continues to blow. Aurora alerts: text, voice.
Realtime Aurora Photo Gallery
BIG SUNSPOTS IN THE MORNING: Sunspot AR1654 is so large, people are starting to notice it with their naked eyes when the sun is dimmed by clouds or mist. This morning, Jan. 14th, Göran Strand photographed the behemoth at sunrise over Frösön, Sweden:
"The weather was very cold, -20 degrees Celsius and there was a light mist that made it possible to shoot right at the Sun without any filters," says Strand. "In the foreground you can see the downpipes on my neighbor's house."
To take the picture, Strand set his Nikon D800E digital camera as follows: 510mm/f4.8, ISO 400, 1/6000 sec. Sky watchers who wish to photograph the spot should take note of those settings, but be careful. Even when the sun is dimmed, viewing it through unfiltered optics is every dangerous. One stray beam of magnified sunlight can blind you. Use the digital viewfinder to safely align the camera.
If there is a flare today, the blast would be Earth-directed. This sunrise shot, taken at dawn on Jan. 16th by Jan Koeman on the bank of the Westerschelde River in the Netherlands, shows how AR1654 (circled) is almost directly facing our planet:
"Sunspot complex AR1654-AR1656 was clearly visible through the clouds and mist," says Koeman. "It was a wonderful sunrise even at -8 degrees celsius."
COMET OF THE CENTURY? Later this year, Comet ISON could become bright enough to see in broad daylight when it passes through the atmosphere of the sun. At the moment, however, it is a cold and lonely speck barely visible through backyard telescopes. Two nights ago, Pete Lawrence of Selsey, UK, photographed the potentially-great comet moving through space near the orbit of Jupiter:
"I created this animation using images taken through a 4-inch refractor, starting at 23h on the 15th of January and ending at 01h on the 16th," says Lawrence. "The comet is clearly visible moving among the stars of Gemini, in an area just to the south of Castor."
Comet ISON looks so puny now because it is more than 600 million km away. In late 2013, however, it will be much closer. A key date is Nov. 28th when Comet ISON flies through the solar corona only 1.2 million km from the surface of the sun. If the comet survives the encounter--a big IF--it could emerge glowing as brightly as the Moon with a sensational tail sure to create a worldwide sensation. Stay tuned!
NORTHERN LIGHTS: A solar wind stream hit Earth's magnetic field on Jan. 26th, sparking auroras around the Arctic Circle. The moon was full at the same time, shining like a floodlight, but the auroras were bright enough to be seen anyway:
Matt Melnyk took the picture from a spot just outside Edmonton, Alberta. "The Moon was bright but it did not stop the aurora from showing!" he says. "The display started off dim then exploded into a vast array of green and purple."
NOAA forecasters estimate a 40% chance of polar geomagnetic storms on Jan. 27th. However, Earth is exiting the solar wind stream, and this will reduce the chances of more bright Northern Lights tonight. Aurora alerts: text, voice.
GREEN COMET LEMMON: 2013 could be the Year of the Comet. Comet Pan-STARRS is set to become a naked eye object in march, followed by possibly-Great Comet ISON in November. Now we must add to that list green Comet Lemmon (C/2012 F6). "Comet Lemmon is putting on a great show for us down in the southern hemisphere," reports John Drummond, who sends this picture from Gisborne, New Zealand
"I took the picture using a 41 cm (16 in) Meade reflector," says Drummond. "It is a stack of twenty 1 minute exposures." That much time was required for a good view of the comet's approximately 7th-magnitude coma ("coma"=cloud of gas surrounding the comet's nucleus).
Lemmon's green color comes from the gases that make up its coma. Jets spewing from the comet's nucleus contain cyanogen (CN: a poisonous gas found in many comets) and diatomic carbon (C2). Both substances glow green when illuminated by sunlight in the near-vacuum of space.
Discovered on March 23rd 2012 by the Mount Lemmon survey in Arizona, Comet Lemmon is on an elliptical orbit with a period of almost 11,000 years. This is its first visit to the inner solar system in a very long time. The comet is brightening as it approaches the sun; light curves suggest that it will reach 2nd or 3rd magnitude, similar to the stars in the Big Dipper, in late March when it approaches the sun at about the same distance as Venus (0.7 AU). Northern hemisphere observers will get their first good look at the comet in early April; until then it is a target exclusively for astronomers in the southern hemisphere.
The eruption was both energetic and photogenic. Click to view a full-disk movie from NASA's Solar Dynamics Observatory:
A close-up of the blast site shows an inky-dark plume of plasma spiralling away from the explosion. Some of that material could be heading in our direction now.
CORONAL HOLE: A vast hole in the sun's atmosphere--a "coronal hole"--has opened up in the sun's northern hemisphere, and it is spewing a stream of solar wind into space. NASA's Solar Dynamics Observatory photographed the UV-dark gap during the early hours of Feb. 5th:
Coronal holes are places where the sun's magnetic field opens up and allows solar wind to escape. Material flowing from this particular coronal hole should reach Earth's orbit on Feb. 7-8. Because of the opening's high northern latitude, the solar wind stream will not hit Earth head on; instead it could be a glancing blow. Even so, the impact could spark polar auroras later this week. Aurora alerts: text, voice.
LOUD SOLAR RADIO BURST: Last Saturday, Feb. 2nd, the solar activity forecast called for "quiet." In fact, says amateur radio astronomer Thomas Ashcraft, "it was really loud. There were several strong solar radio emissions including one super-strong Type III burst at 1954 UT. I captured it at 28 MHz and 21.1 MHz as it totally drowned out a shortwave voice transmission." Click to listen:
Dynamic spectrum credit: Dick Flagg, Windward Community College Radio Observatory, Oahu, Hawaii
The source of the burst was sunspot AR1667, which unleashed a C2.9-class solar flare just before the roar emerged from the loudspeaker of Ashcraft's radio telescope. Type III solar radio bursts are produced by electrons accelerated to high energies (1 to 100 keV) by solar flares. As the electrons stream outward from the sun, they excite plasma oscillations and radio waves in the sun's atmosphere. When these radio waves head in the direction of Earth, they make themselves heard in the loudspeakers of shortwave radios around the dayside of the planet.
COMET LEMMON UPDATE: Glowing much brighter than expected, Comet Lemmon (C/2012 F6) is gliding through the skies of the southern hemisphere about 92 million miles (0.99 AU) from Earth. Amateur astronomer Rolf Wahl Olsen sends this picture from his backyard in Auckland, New Zealand:
"I took this image of Comet Lemmon on the 28th of January," says Olsen. "It has become quite bright now and has also grown a beautiful tail."
Discovered on March 23rd 2012 by the Mount Lemmon survey in Arizona, Comet Lemmon is on an elliptical orbit with a period of approximately 11,000 years. This is its first visit to the inner solar system in a very long time. The comet is brightening as it approaches the sun; light curves suggest that it will reach 2nd or 3rd magnitude, similar to the stars in the Big Dipper, in late March when it approaches the sun at about the same distance as Venus (0.7 AU).
At the moment, the comet is glowing like a 7th magnitude star, just below the limit of naked-eye visibility. To capture the faint details of the comet's filamentary tail, Olsen used a 10-inch telescope, a sensitive CCD camera, and an exposure time of 1 hour 17 minutes. Complete photo details are given here.
Northern hemisphere observers will get their first good look at the comet in early April; until then it is a target exclusively for astronomers in the southern hemisphere.
RUSSIAN METEOR STRIKE: On Friday, February 15th at 9:30 am local time in Russia, a small asteroid struck the atmosphere over the city of Chelyabinsk and exploded. According to reports from news organizations and Russian authorities, as many as 1000 people received minor injuries from the shock wave. This is the most energetic recorded meteor strike since the Tunguska impact of 1908.
Researchers have conducted a preliminary analysis of the event. "Here is what we know so far," says Bill Cooke, head of NASA's Meteoroid Environment Office. "The asteroid was about 15 meters in diameter and weighed approximately 7000 metric tons. It struck Earth's atmosphere at 40,000 mph (18 km/s) and broke apart about 12 to 15 miles (20 to 25 km) above Earth's surface. The energy of the resulting explosion was in the vicinity of 300 kilotons of TNT." (continued below)
"A shock wave propagated down and struck the city below, causing large numbers of windows to break, some walls to collapse, and minor damage throughout the city," he continued. "When you hear about injuries, those are undoubtedly due to the effects of the shock wave, not due to fragments striking the ground. There are undoubtedly fragments on the ground, but as of this time we know of no recovered fragments that we can verify."
Videos of the event may be found here and here. In many of the videos you can hear the sound of windows shattering as the meteor's loud shock wave reaches the ground. Onlookers cry out in Russian as alarms and sirens sound in the background. This pair of wide-angle gif animations is also worth watching: #1, #2.
It is natural to wonder if this event has any connection to today's record-setting flyby of asteroid 2012 DA14. Paul Chodas of the Near Earth Object Program at JPL says no. "The Russian fireball is not related to 2012 DA14 in any way. It's an incredible coincidence that we have had these two rare events in one day."
Stay tuned for updates!
GOOD-BYE 2012 DA14: Asteroid 2012 DA14 few past Earth on Feb. 15th inside the orbit of many geosynchronous satellites. At closest approach, around 2:25 pm EST, the 45-meter wide space rock was only 17,200 miles above Indonesia. No satellites were damaged by the flyby, and the asteroid is now receding from Earth.
Using a 3" refractor at the Siding Spring Observatory in Australia, Aaron Kingery captured this image of 2012 DA14 passing in front of the eta Carina Nebula:
NASA's Goldstone radar in the Mojave Desert will ping the space rock for the next four days to refine its orbit and map its surface features. Researchers will look carefully for signs that Earth's gravity might have caused seismic activity on the asteroid.
M-CLASS SOLAR FLARE: Yesterday, Feb. 17th, new sunspot AR1675 unleashed the most intense flare of the year so far, an M1.9-class explosion. NASA's Solar Dynamics Observatory captured a double-flash of extreme UV radiation from the explosion:
Coronagraph images from SOHO and the twin STEREO probes show that this explosion did not produce a coronal mass ejection (CME). Nevertheless, there were some Earth-effects. UV radiation from the flare produced a wave of ionization in Earth's upper atmosphere. Radio listeners in Europe and North America detected the sudden ionospheric disturbance. Solar flare alerts: text, voice.
RUSSIAN METEOR UPDATE: On Friday, February 15th at 9:30 am local time in Russia, a small asteroid struck the atmosphere over the city of Chelyabinsk and exploded. According to reports from news organizations and Russian authorities, as many as 1000 people received minor injuries from the shock wave. This is the most energetic recorded meteor strike since the Tunguska impact of 1908.
Note: In the following paragraph, bold-faced numbers were updated on Feb. 17th to reflect new and improved estimates of the asteroid's size and energy. It was even bigger than we thought!
Researchers have conducted a preliminary analysis of the event. "Here is what we know so far," says Bill Cooke, head of NASA's Meteoroid Environment Office. "The asteroid was about 17 meters in diameter and weighed approximately 10,000 metric tons. It struck Earth's atmosphere at 40,000 mph (18 km/s) and broke apart about 12 to 15 miles (20 to 25 km) above Earth's surface. The energy of the resulting explosion was in the vicinity of 500 kilotons of TNT." (continued below)
It is natural to wonder if this event has any connection to Friday's record-setting flyby of asteroid 2012 DA14. Paul Chodas of the Near Earth Object Program at JPL says no. "The Russian fireball is not related to 2012 DA14 in any way. It's an incredible coincidence that we have had these two rare events in one day."
"I saw Comet Pan-STARRS just before daybreak in the constellation Grus," says Bobillo. "This is what it looked like through a small telescope, imaged with an exposure time of 8x2 minutes."
In early March, Comet Pan-STARRS will make its closest approach to the sun inside the orbit of Mercury; at that time it could brighten to easy naked-eye visibility. No one knows exactly what will happen, however, because it is a fresh comet being exposed to solar heating for the first time. Experts discuss the possibilities in this video from Science@NASA. More: 3D orbit, ephemeris, light curves, NASA story.
Realtime Comet Photo Gallery
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