CME Tagged ‘CME’

Interesting Stuff re:10/25 Solar Flare

Sunday, October 27th, 2013

X2-FLARE BLASTS EARTH’S IONOSPHERE: Electromagnetic radiation from the X2-class solar flare of Oct. 25th had a significant effect on Earth’s upper atmosphere. As a wave of ionization swept across the dayside of the planet, the normal propagation of shortwave radio signals was scrambled. In Alachua, Florida, electrical engineer Wes Greenman recorded the effects using his own shortwave radio telescope. Click on the frequency-time plot to view an animation:

During the time that terrestrial shortwave transmissions were blacked out, the sun filled in the gap with a loud radio burst of its own. In New Mexico, amateur radio astronomer Thomas Ashcraft recorded the sounds. “This radio burst was a strong one and might be too intense for headphones,” cautions Ashcraft.

Solar radio bursts are caused by strong shock waves moving through the sun’s atmosphere. (Electrons accelerated by the shock front excite plasma instabilities which, in turn, produce shortwave static.) They are usually a sign that a CME is emerging from the blast site–and indeed this flare produced a very bright CME.


Big Solar Flare

Saturday, October 26th, 2013

INTERCONNECTED SOLAR ACTIVITY: The X1-flare of Oct. 25th was remarkable not only for its strength, but also for its interconnectedness. The flare was bracketed by two erupting magnetic filaments, each located hundreds of thousands of kilometers from the instigating sunspot AR1882. The whole episoide, shown in this SDO movie, was reminiscent of the famous global eruption of August 2010.

Today, Oct. 26th, it happened again. Click on this image of the sun’s southwestern quadrant and watch a sequence of flare activity around sunspots AR1875 and AR1877 followed by a filament eruption off the SW limb:

Instead of being a sequence of unrelated events, these flares and eruptions are likely connected by magnetic fields, which thread through the whole broad region. Like dominoes falling, one explosion triggers another as shock waves follow magnetic fields from blast site to blast site.

The filament punctuated the sequence by hurling a part of itself into space. SOHO has observed a CME emerging from the blast site, but it is too soon to say whether it is heading for Earth.


More SOlar Flares

Thursday, October 24th, 2013

SOLAR FLARE! Solar activity is high. On October 24th at 00:30 UT, Earth-facing sunspot AR1877 erupted, producing a powerful M9-class solar flare. NASA’s Solar Dynamics Observatory recorded the blast:

Update #1: The eruption hurled a faint CME into space and it appears to be heading toward Earth. The arrival time is not yet known.

Update #2: NASA’s Solar Dynamics Observatory has released a full-disk movie of the explosion. Play it.

More flares are in the offing. Two large sunspots, AR1875 and AR1877, have ‘beta-gamma-delta’ magnetic fields that harbor energy for strong eruptions. NOAA forecasters estimate a 40% chance of M-flares and a 5% chance of X-flares during the next 24 hours.


A Waking Sun

Friday, October 11th, 2013

FARSIDE ERUPTION: An active region located just behind the sun’s northeastern limb erupted this morning, producing an X-ray flash that registered M1.5 on the Richter Scale of Solar Flares — despite the fact that it was partially eclipsed by the edge of the sun. The true intensity of the flare was much greater, possibly X-class. The explosion also hurled a spectacular CME into space:

Type II radio emissions from the expanding cloud suggest an expansion velocity of at least 510 km/s (1.1 million mph). That’s a typical speed for CMEs.

Within a few days, the sunspot responsible for this outburst will rotate around to the Earthside of the sun. At that time, Earth-directed solar activity could increase. August and September were quiet months, but in October the sun seems to be waking up


New Coronal Hole

Sunday, September 22nd, 2013

CORONAL HOLE: NASA’s Solar Dynamics Observatory is monitoring a coronal hole in the sun’s northern hemisphere. It is the UV-dark region in this image taken during the early hours of Sept. 21st:

The white lines in the image trace the sun’s magnetic field. A coronal hole is a place where the magnetic field spreads apart, allowing solar wind to escape. A stream of solar wind flowing from this particular coronal hole is heading for Earth, due to arrive on Sept. 23-24. Its arrival could add to the impact of a minor CME expected to reach Earth at about the same time. Polar geomagnetic storms are possible early next week.


Comets & CME

Tuesday, August 20th, 2013

SUNDIVING COMET AND FULL-HALO CME: A small comet plunged into the sun this morning, and just before it arrived, the sun expelled a magnificent full-halo CME. Click to view a movie from the Solar and Heliospheric Observatory (SOHO):

In the final frames of the movie, the comet can be seen furiously vaporizing. Indeed, those were the comet’s final frames. It did not emerge again from its flyby of the hot sun. “With a diameter of perhaps a few tens of meters, this comet was clearly far too small to survive the intense bombardment of solar radiation,” comments Karl Battams of the Naval Research Lab, who studies sungrazing comets.

The CME (coronal mass ejection) came from an explosion on the farside of the sun. Although the CME and the comet appear to intersect, there was probably no interaction between the two. The comet is in the foreground and the farside CME is behind it.

Occasionally, readers ask if sundiving comets can trigger solar explosions. There’s no known mechanism for comets to spark solar flares. Comets are thought to be too small and fragile to destabilize the sun’s magnetic field. Plus, this comet was still millions of kilometers from the sun when the explosion unfolded.

The comet, R.I.P., was a member of the Kreutz family. Kreutz sungrazers are fragments from the breakup of a single giant comet many centuries ago. They get their name from 19th century German astronomer Heinrich Kreutz, who studied them in detail. Several Kreutz fragments pass by the sun and disintegrate every day. Most, measuring less than a few meters across, are too small to see, but occasionally a bigger fragment like this one attracts attention.


New Sunspot Activity

Monday, August 12th, 2013

BREAK IN THE QUIET: Solar activity has been low for weeks. The emergence of sunspots AR1817 and AR1818 could break the quiet. Both pose a threat for M-class solar flares. AR1817 has already produced one almost-M class eruption:

The C8-category flare was recorded by NASA’s Solar Dynamics Observatory on August 11th at 2158 UT. Whether it is a herald of bigger things to come remains to be seen. AR1817 is almost directly facing Earth, so any eruptions this week will probably be geoeffective.


Large Sunspot Eruptions

Monday, July 8th, 2013

BIG SUNSPOT FACES EARTH: Colossal sunspot AR1785 is now directly facing Earth. The active region has a ‘beta-gamma-delta’ magnetic field that harbors energy for X-class flares, yet so far the sunspot has been mostly quiet. Could it be the calm before the storm? NOAA forecasters estimate a 55% chance of M-flares and a 10% chance of X-flares on July 8th.

Sprawling more than 11 Earth-diameters from end to end, AR1785 is one of the biggest sunspots of the current solar cycle. In fact, it can barely fit on the screen. Click on the dark core below to see a complete hi-res picture taken by Christian Viladrich of Nattages, France:

To take the picture, Viladrich used a filtered 14-inch Celestron telescope. All those irregular blobs surrounding the primary dark core are boiling granules of plasma as small as the state of California or Texas. It’s a very sharp picture.


New Impressive Solar Flare 6/24

Monday, June 24th, 2013

M-CLASS SOLAR FLARE: Sunspot AR1778 produced an impulsive M2-class solar flare on June 23rd at 20:56 UT. NASA’s Solar Dynamics Observatory recorded the extreme ultraviolet flash:

The eruption flung material away from the blast site, but the debris does not appear to be heading toward Earth. Except for the effects of the UV flash, which created a short-lived wave of ionization in Earth’s upper atmosphere, this flare was not geo-effective.

More flares could be in the offing. In addition to AR1778, sunspots AR1775 and AR1776 have ‘beta-gamma’ magnetic fields that harbor energy for significant eruptions. NOAA forecasters estimate a 40% chance of M-flares and a 5% chance of X-flares on June 24th.


Solar Flare

Friday, June 21st, 2013

SOLSTICE SOLAR FLARE: This morning, June 21st at 03:16 UT, the sun itself marked the solstice with an M2-class solar flare from sunspot AR1777. NASA’s Solar Dynamics Observatory photographed the extreme ultraviolet flash and a plume of material flying out of the blast site:

As sunspots go, AR1777 is neither large nor apparently menacing, yet it has been crackling with flares for days. Before it rotated over the sun’s eastern limb on June 20th, it unleashed a series of farside flares and CMEs. Today’s explosion was not Earth directed, but future explosions could be as the sun’s rotation continues to turn AR1777 toward our planet. NOAA forecasters estimate a 30% chance of M-flares and a 5% chance of X-flares during the next 24 hours.