Intense Solar Flare Activity

23 October 2003

Intensely active Region 486, now moving into slightly better view around the southeastern solar limb, continues to put on quite a show. At 08:35 UTC on 23 October (4:35 am EDT), this region spawned a powerful class X5.4 x-ray flare. The pair of images below, taken in extreme ultraviolet light by the SOHO spacecraft, shows activity on the southeast limb before and at the maximum intensity of the solar flare.

This event has been confirmed with a large coronal mass ejection off the east limb of the Sun, as the following images from the LASCO instrument on SOHO indicate:

Solar activity is expected to continue at high levels into the forseeable near future (at least the next 72 hours). It is not yet known whether this coronal mass ejection will have a glancing impact with the Earth. For updated information concerning this, please visit the forecast notes on our main web page at: www.spacew.com.

Major X-Class Solar Flare

20 October 2003

A large class X1.1/1N solar flare was observed at 16:50 UTC (12:50 pm EDT) on 19 October following a period of remarkable and rapid growth from active sunspot Region 484. The sunspot complex grew from the size indicated in the left frame below to the size indicated in the right frame, in 48 hours. It is now visible to the unaided (protected) eye!

This remarkable growth allowed powerful magnetic fields to become intertwined sufficiently to promote energetic magnetic explosions - or solar flares. This intertwining of magnetic fields can be inferred from magnetograms of the active region, as the following illustrates:

As these images show, the active region contains two strong sunspots in close proximity to each other. They are, in fact, so close to each other that their penumbral areas (the brownish-coloring around the black umbral spots) have merged into a single penumbral mass. When opposite polarity umbral spots are located within a single penumbra as Region 484 clearly is, a magnetic "delta" condition is formed. Sunspots that become magnetic deltas are capable of energetic (major-category) solar flares, particularly when the umbrae are as large and strong as Region 484's.

The magnetogram above shows the two primary spots of Region 484. The black areas represent negative magnetic polarity while the white areas represent positive polarity. Using magnetograms, it is easy to determine if opposite polarity sunspots in an active region have formed a magnetic delta configuration.

The most intense solar flare activity typically occurs near the neutral line (the red line drawn in the magnetogram above) that separates the positive and negative magnetic fields of the region. This area is also involved with higher magnetic gradients and stronger levels of magnetic shear, which are important parameters in the development of energetic solar flares.

Region 484 is capable of producing additional major solar flares over the coming days. Some of these events may be associated with Earthward-directed coronal mass ejections which could promote periods of strong auroral activity ("Northern Lights") during the next week.

Multiple Major Solar Flares

11 June 2003

Numerous major solar flares including two X-class solar flares have been observed over the last several days from active sunspot Region 10375 (nicknamed '375'). This sunspot complex, shown below, is very large and is visible to the unaided eye.

(Courtesy SOHO [left] and Big Bear Solar Observatory [right])

The latest X-class solar flare from this region was observed at 8:02 pm EDT on 10 June (00:02 UTC on 11 June). Additional major solar flare activity is probable from this active region as it begins to approach the western solar limb over the next 3 to 4 days.

Also of interest is Region 10380, which is gradually growing. At slightly less than half the present size of Region 10375, this region isn't quite as volatile, but it still has potential. Characteristics observed recently in this active sunspot complex suggest it may be capable of supporting major solar flare activity as well - particularly if growth persists.

Both of these active regions are visible to the unaided eye using appropriate protective shielding. Never look at the sun directly or without appropriate shielding. Some material may make the Sun appear dark, but may not shield your eyes from invisible forms of damaging radiation. Only use proven protective shielding to observe these sunspots.

Old Region 10365 is also apparently up to its old antics, even though it is now traversing the opposite side of the Sun. The SOHO LASCO instrument observed this full-halo coronal mass ejection from a source located nearly directly opposite the Earth, behind the Sun, and in a location where old Region 10365 is expected to be.

Note the weak halo of light that erupts around the occulting disc and expands outward - the signature of a halo coronal mass ejection. This mass ejection appears to be travelling directly away from the Earth on the far side of the Sun and poses no threat to the Earth.

Although there is no solid evidence suggesting that any of the coronal mass ejections observed from the recent flurry of energetic solar flares are directed Earthward, there is a slight chance the Earth may intersect some flanking portions of the activity. If this occurs, there may be a mild enhancement in levels of auroral activity ("northern lights") over the next several days. Most space weather forecasters are of the opinion that the Earth will not see much of anything from the observed solar activity.

Multiple X-Class Solar Flares

29 May 2003

Active sunspot complex 10365 (shown below) has produced three X-class flares during the last 48 hours. Each of these solar flares has been associated with strong radio emissions and Earthward-directed coronal mass ejections.

The solar flare itself was imaged by the Culgoora Solar Observatory in Australia (courtesy of IPS, Australia) and is depicted in the following pair of images. The first image was acquired a few minutes before the solar flare. The second image shows the solar flare at its maximum phase. The third image is a brief movie showing what this solar flare (and the rest of the Sun) looked like in x-rays, courtesy of the new GOES-12 soft-xray imager (SXI) instrument:

This active region is expected to produce additional major M and/or X-class solar flares over the coming days. The latest major X-class flare from this region occurred at 01:06 UTC on 29 May (9:06 pm EDT on 28 May). The coronal mass ejection produced by this flare was similar to the others that this region has produced and is illustrated below.

This image was provided by subtracting the components of two consecutive images from the SOHO LASCO C3 instrument. It shows the progression and the approximate velocity of the coronal mass ejection as it propagates outward from the Sun. The Sun is hidden by an occulting disc (the gray circle in the middle of the image). The whiter emissions that expand outward and surround the occulting disc are produced when the coronal mass ejection (which has a trajectory nearly directly toward the Earth) balloons outward toward the Earth. The rate at which these emissions travel outward are related to the velocity of the coronal mass ejection.

This sequence of images shows two coronal mass ejection features: the first propagates toward the west (the right side of the image) at a higher velocity than the halo CME that immediately follows it. This faster CME may be related to the X-class flare, or it may be a coincident back-sided event. At the present time, there is insufficient information to make an accurate determination. The westward-directed CME has a plane of sky velocity near 1260 km/sec. The inner full halo CME has a plane of sky velocity estimated near 920 km/sec. This latter velocity coincides nicely with the observed radio emissions that were observed during the solar flare as the shock front from this explosive mass ejection energized the corona sufficiently to produce strong radio emissions known as sweep frequency events. The estimated velocity of the shock front within the inner corona (measured through radio observations) was estimated near 955 km/sec.

This CME is expected to impact the Earth in the early UTC hours of 31 May (this is equivalent to the late evening hours of 30 May for North American observers).

X-Class Solar Flare Alert

17 March 2003

Active sunspot complex 314 (shown below) experienced rapid growth and intensification of a complex magnetic delta configuration over the last 24 hours. This is believed to have contributed to the eruption of a class X1.5/1B solar flare at 19:06 UTC (2:06 pm EST) on 17 March. This flare was optically rather small, but attained a strong level in x-rays. X-class flares are the most energetic solar flares rated. This solar flare produced a momentary minor increase in energetic proton densities in the near-Earth space environment. The latest data suggests this solar flare was probably not associated with a coronal mass ejection. Indeed, recent SOHO imagery do not show evidence of a CME during the time of the solar flare. An earth-bound impact is therefore not expected.

In the image above, Region 314 is the large sunspot complex closest to the center of the Sun. It continues to possess a complex detla magnetic configuration where opposite magnetic polarity umbrae are contained within a single penumbra. It has produced several minor M-class solar x-ray flares since the major X-class flare. It has the potential to produce another isolated X-class solar flare as well before it rotates behind the western solar limb in about another 4 days.

Possible Energetic Flare Activity

18 December 2002

Active sunspot complex 226 is now crossing the central meridian of the Sun. It was confirmed to be visible to the unaided (but protected) eye on 17 December and will probably remain visible to the unaided eye for several more days as it continues to develop and grow in size and complexity.

This sunspot complex contains a magnetic delta configuration where two umbrae of opposite magnetic polarity are contained within a single penumbra. The location of the dleta configuration has been highlighted in the image below with an arrow.

The location of this delta is easier to determine if a map of the photospheric magnetic fields of the Sun are overlayed on top of this image. The following movie sequence illustrates this by gradually fading in a magnetogram map of the Sun with this white-light image of the Sun, both taken at precisely the same time by the SOHO spacecraft.

Areas in the magnetogram that are white represent positive magnetic polarities. Areas that are black represent negative magnetic polarities. The close proximity of black and white magnetic zones represents areas of intensified magnetic gradients. The location where a bllack sunspot umbra and a white sunspot umbra are contained within a single penumbra is identified as a magnetic delta configuration. The delta in Region 226 is fairly easy to identify, although it is at the present time still fairly small.

The presence of a magnetic delta configuration in Region 226 hints at the possibility for increased levels of energetic solar flare activity over the coming days. There is a developing chance this region may become involved in a larger major solar flare event as well. Thus far, this region has been responsible for several smaller minor M-class x-ray flares. Attendant with the increased probability of energetic flare activity from this spot complex is the possibility for Earthward-directed coronal mass ejections. Although none have yet been observed leaving the Sun from this spot complex, the potential does exist.

The Misplaced X-Class Solar Flare?

01 November 2002

At 16:52 UTC (11:52 am EST) on 31 October 2002, x-ray sensors onboard the Geosynchronous Operational Environmental Satellites (GOES - orbiting approximately 35,800 kilometers [22,300 miles] away from the Earth) observed a sudden and large increase in the amount of solar x-ray radiation output from the Sun. Within approximately 3 minutes, the whole-disc solar x-ray "brightness" of the Sun increased more than 44 times the normal brightness of the Sun. The source of this powerful solar x-ray burst was a solar flare. Although this event was a fairly small X-class event by solar standards, it is turning out to be a rather intriguing one for the simple reason that space weather forecasters have not been able to determine precisely where this solar flare occurred. They are torn between two possibilities: a sunspot complex now rounding the east limb of the Sun, or a sunspot complex (known as Region 10162) departing the western limb of the Sun. The problem is that there were two significant limb events at almost precisely the same time as the X-class x-ray burst (as illustrated below).

(Eenie-meenie-miney-moe... where the flare occurred no one knows.)
This image was provided courtesy of the National Solar Observatory.

Click Here (or on the image) to display a 1.3 megabyte animated GIF movie of this activity.

Another intriguing fact is that these two sunspot complexes are almost exactly 180 degrees apart. If you could stick a metal rod through the centers of these two sunspot regions, the metal rod would come very close to piercing the center of the Sun. Perhaps this is just a coincidence, but solar researchers have known for years that strong active longitudes on the Sun where powerful sunspot complexes sometimes form are often observed on almost exactly the opposite sides of the Sun. Perhaps this is another illustration of this phenomena.

This problem would have been easy to resolve if the x-ray sensors on the GOES spacecraft could resolve specific regions of x-ray emissions on the Sun. Unfortunately, all of the presently operational GOES spacecraft (GOES-8 and GOES-10) only contain full-disc x-ray sensors. In other words, these spacecraft can only see x-rays from the whole sun. In several months (probably sometime near or shortly after January 2003), the new GOES-12 satellite will replace the aging GOES-8 spacecraft. This will be a significant transition for space weather forecasters because the new GOES-12 spacecraft contains a special camera capable of imaging the Sun in x-rays at high cadence (very rapidly). It will remove the "blindness" of the older GOES spacecraft by allowing space weather forecasters to see not only how strong energetic x-ray flares are, but where they occur on the Sun.

Had this capability been operational at the time of this latest X-class x-ray flare event, forecasters would have probably found x-ray contributions from both of these active sunspot complexes. The combined x-ray output of both of these active regions were probably responsible for the X-class amplitude of the x-rays observed. But activity in one of these regions was probably more energetic than the other. Which was the most energetic, no one yet knows for certain.

The activity observed on the northwest limb (upper-right quadrant in the above image) does not appear to have been immediately associated with a coronal mass ejection. But the event off the southeastern limb was. The southeastern limb event was associated with a small, but high velocity coronal mass ejection. The velocity of the CME was determined to be near 1,100 kilometers per second. The narrow CME is visible in LASCO instrument images of the solar corona obtained from the SOHO spacecraft.

This stacked frame shows the progression of the ejected mass (the white areas denoted by the arrows). These images were obtained by subtracting images taken at slightly different times. Gray areas represent areas of the image that have not changed from one image to the next. White areas show new changes and black areas show old changes. The white and black blocks in the lower image are noise artifacts (not real). These images are available in near real-time and are exceptionally useful for monitoring the state of the Sun's corona, as well as detecting coronal mass ejections. It is also interesting to note that the planet Venus is visible (almost) in these differenced images. Non-differenced LASCO images clearly show the bright planet gradually progressing along its orbit over time. But since its brightness doesn't change, it appears in these differenced images as an indiscrete gray color.

As our previous AstroAlert suggested, there is the potential for additional impressive and dynamic solar limb activity over the next few days. There is also a chance we may see additional major x-ray flares over the coming week or two if the active sunspot complex responsible for this latest X-class solar flare originated with the spot complex behind the southeast limb. That sunspot region will gradually rotate into better view over the next several days, while old Region 10162 will be lost behind the northwest limb. The area of primary interest will now switch from Region 10162 on the west limb to the new active spot complex on the southeast limb.

Monitor current conditions from your own home using our advanced Space Weather Information Monitor (Windows NT, 2000 or XP) or our less advanced Aurora Monitor (Windows 95, 98, Me, NT, 2000, XP) software. Trial versions of these software packages are available.

Current conditions can also be monitored at: http://www.spacew.com/plots.html.

Impressive Prominence Eruptions Observed

26 October 2002

An impressive sequence of prominence eruptions was caught by the Solar and Heliospheric Observatory (SOHO) on 25 October. As luck would have it, the SOHO spacecraft commenced a campaign of observing the Sun at a wavelength that is excellent for monitoring prominence activity, just as two very large prominences began erupting. The following GIF image animation (681 kb) shows the eruption across 6 frames. For a much higher quality animation, download the ~3 megabyte mpeg movie of this event at: http://sohowww.nascom.nasa.gov/data/LATEST/current_eit_304.mpg. This link will only remain valid for the next 24 to 48 hours. Thereafter, it will be necessary to go to the SOHO site and download the EIT304 movie from their archive area.

The SOHO LASCO Science team believes the second prominence eruption resulted in a full halo (Earthward-directed) coronal mass ejection (CME). However, we believe this CME actually originated from a source located on the back side of the Sun. Details regarding these events are available on our CME Impact Prediction page.

Large Sunspot Complex Visible

Large Sunspot Visible to Unaided Eye
and 07-08 September Auroral Storm

Major X-Class Solar Flare Alert

30 August 2002

A major class X1.56 solar x-ray flare was observed from active sunspot complex 10095 at 13:29 UTC (9:29 am EDT) on 30 August. This spot complex has shown dynamic activity since it first appeared on the north eastern solar limb a few days ago. Numerous M-class flares (10 times less powerful than today's X-class x-ray flare) were observed as the spot group rotated into view. Today's major X-class flare was easiest to see in the SOHO EIT 195 Angstrom images (reproduced below):

The solar flare was diminuitive in hydrogen-alpha, but was captured by the Kanzelhohe Solar Observatory in Austria:

The X-class solar flare was not very powerful in terms of its overall energy output. Although it sported some modest radio emissions at microwave and lower frequencies, the duration of the flare itself was fairly short (about 10 minutes for the X-class event itself). Such short duration events are often not associated with strong coronal mass ejections. Indeed, the latest preliminary SOHO LASCO imagery does not show any significant coronal mass ejection activity associated with this flare event.

Kanzelhohe and SOHO produced near-simultaneous images of the Sun at two different wavelengths: hydrogen-alpha (6563 Angstroms) and extreme ultraviolet (195 Angstroms). For fun, we have combined the h-alpha and EIT images at 13:36 UTC together to show the how common features align in both wavelengths:

A few of the more interesting features of these two images are described in the annotated image below:

A large coronal hole (an area where magnetic field lines from the Sun don't loop immediately back to the Sun, but are instead dragged out into interplanetary space) is visible in the northern polar region with an extension or "tongue" dropping down toward the middle solar latitudes. A second coronal hole is visible approaching the solar equator from the southern polar regions. This coronal hole may become the source of a higher velocity solar wind stream several days from now - which may help invigorate higher latitude auroral activity.

Notice how filaments are always located within the cooler (darker) regions of the EIT images. This is because filaments are strings of matter that are suspended above the surface of the Sun and are cooler than their surroundings. This also explains why they appear dark in H-alpha images - they are cooler, just like sunspots.

Active Region 10087 (nicknamed '87') is gradually decaying, but contains some hot areas that appear brighter in both the EIT imagery and the H-alpha imagery. When seen near the limbs, active regions produce visible loops of hotter coronal material which define the shape and location of magnetic flux tubes that punch through the surface of the Sun in active regions and loop back to other locations. The interaction of these magnetic loops can help to trigger solar flares.

Prominences are synonymous with filaments. The only difference is that the suspended gas is observed against the cold blackness of space. As a result, they appear bright.

Another interesting and revealing look at the Sun is obtained by merging the EIT images with magnetic field maps (magnetograms) of the Sun. Both of the images above were obtained by the SOHO spacecraft. They are nearly co-aligned - the magnetogram image (on the right) was obtained a few hours earlier than the EIT image on the left. But the alignment is close enough for our purposes.

Click on the image above if you want to download a 1.3 megabyte GIF image movie that fades from the EIT image to the magnetogram image. It may better illustrate the concepts discussed below.

The animation clearly shows how each of the hot spots (bright in EIT) are associated with strong negative (black) and positive (white) magnetic fields on the Sun. Every active sunspot group is also identifiable by these white and black magnetic field markers. In the northern hemisphere, positive (white) polarity sunspots almost always precede the negative (black) polarity flux. In the southern solar hemisphere, the reverse is true. Each new solar cycle sees this entire pattern reverse - that is, during the next solar cycle, the northern hemisphere will see negative polarity magnetic flux precede the positive polarity flux.

The closer together bright white areas are to the black areas, the stronger the magnetic gradients are within the sunspot complex. Strong magnetic gradients can result in a considerable amount of stored magnetic energy which can occassionally be released in the form of a solar flare. Rapid emergence of sunspots with twisted or complex morphologies can also lead to the occurrence of frequent flare activity. The emergence of new magnetic flux within a pre-existing magnetic field can also result in solar flare activity. For example, if a strong negative polarity spot began to emerge rapidly within any of the existing bright white areas on the magnetogram image above, frequent magnetic reconnections could take place, leading to frequent solar flare activity. Flaring would probably continue until a new stable magnetic configuration had been achieved.

Examine the annotated image in this AstroAlert to identify the location of one of the polar coronal holes with their attendant appendages into the middle solar latitudes. It is possible to determine the polarity of these coronal holes by examining the polarity of the photospheric magnetic fields (see the magnetogram above) directly under the coronal hole. If the proportion of negative (black) magnetic fields exceeds the proportion of positive (white) magnetic fields under the coronal hole, then the coronal hole is labelled as negative in polarity. Sometimes the relative proportions are very subtle and difficult to discern without looking at more sensitive magnetograms. In the sequence of images taken today, the coronal hole in the southern solar hemisphere is the easiest to discern the polarity, which is positive (white). The northern polar coronal hole is negative (black) in polarity.

Polarity of coronal holes are important because they determine the orientation that the interplanetary magnetic field (IMF) will have in the solar wind near the Earth. And this polarity can have a bearing on how the Earth's own magnetic field may respond to the higher velocity solar wind stream when it reaches the Earth.

Finally, a close examination of the animated GIF image reveals that the X-class solar flare (the bright spot in the upper-left) appears to have occurred at a location between positive and negative polarity flux in the sunspot complex nearing the northeast limb. Watch where the bright spot appears in the animation with respect to the location of the magnetic fields. This is normal, for this is where the magnetic field is probably the most complex and gradients are the highest. This is a poor example to illustrate flare magnetic fields because magnetograms become inaccurate the closer the structures are to the limb. As a result, the true magnetic complexity of this active sunspot complex won't become apparent for several more days, after the sunspot group has rotated well away from the limb and the magnetic fields associated with it can be more easily discerned with telescopic equipment.

Additional minor and major solar flares are expected from this spot complex over the coming days. Whether the source of the instability persists over the next week (when the group will be in a much better position to launch coronal mass ejections toward the Earth) remains to be seen. Additional AstroAlerts will be posted, as necessary.

High Solar Limb Activity Alert

Major Solar Flare and High Velocity CME

Active sunspot complex 10069 continues to grow in both size and magnetic complexity. New magnetic flux continued to emerged north and west of the main leader spot. New flux is also beginning to emerge southwest of the main leader spot. There are now four distinct magnetic delta configurations where opposite magnetic polarity umbrae are located within a single penumbra. This very complex sunspot group produced a long-duration major class M5.2 solar x-ray flare at 12:32 UTC (8:32 am EDT) on 16 August. Accompanying this flare was a high velocity coronal mass ejection estimated to be travelling near 1,400 kilometers per second (875 miles per second). High energy protons at greater than 10 MeV are beginning to be observed in the near-Earth space environment from this event (a separate minor proton enhancement followed a west limb event flare earlier in the day). The solar flare was observed in hydrogen alpha by the Kanzelhohe Solar Observatory in Austria and is shown below just prior to the clouds obscuring Kanzelhohe's view:

(Above: shortly after the peak of the flare in x-rays.)
(Below: full-halo CME from the major flare.)

(Below: the high velocity coronal mass ejection associated with the major flare.)

(Below: Active Sunspt Complex 10069 in all its enormous splendor - white-light, courtesy BBSO):

The area of new flux growth is shown by "New Spots." The magnetic neutral lines (where the polarity reverses) are drawn as lines through the spot complex. The polarity of the respective regions are also identified as positive (+) or negative (-). Significant activity often involves any one or more of the neutral lines. White light flares are also often observed in the penumbral regions near the neutral lines.

(Below: Visible to the unaided eye, Region 10069 dominates the visible disk of the Sun; courtesy SOHO):

The high velocity shock front leading the coronal mass ejection into space is expected to impact the Earth late in the UTC day of 17 August or very early in the UTC day of 18 August (late afternoon or very early evening hours of 17 August for North Americans). A major geomagnetic storm is expected to accompany the arrival of this disturbance at the Earth on 18 August. Periods of minor to major storming with intervals of severe geomagnetic and auroral storming are expected after the disturbance arrives. On the G-scale adopted by NOAA, this storm is predicted to reach a G2 to G3 level (on a scale that peaks at G5).

Potentially significant and widespread auroral storming is expected to accompany this disturbance, with observations possible perhaps well into the central U.S. states and central Europe. A middle latitude auroral activity WARNING (not a watch) is being issued for the late-17th to 19 August time frame (expressing the increased confidence of a potentially strong auroral disturbance), but with heaviest emphasis on 18 August. Unfortunately, the waxing phase of the moon will inhibit observations of intricate auroral activity. However, auroral storming may frequently be strong enough to easily override the brightness of the moon.

Additional isolated major M and X class solar x-ray flares with potentially influential coronal mass ejections are expected over the coming days. There is also a possibility of a white-light solar flare from this spot complex. Refer to the sunspot diagram above for locations of neutral lines where white light emissions are often observed during strong solar flares.

Please submit any sightings of auroral activity to the Global Auroral Activity Observation Netowork. Stay informed on the Discussion Forum. Software is available to help monitor conditions in real-time - click here for SWIM (Windows NT4, 2000 or XP), or click here for the Aurora Monitor (Windows 95, 98, Me, NT4, 2000 or XP). SWIM is the most sophisticated space weather monitoring software in the world.

Naked Eye Sunspot Complex

A large and magnetically complex sunspot group recently rotated into view around the southeastern limb of the Sun. Identified as active sunspot region number 10069 (abbreviated simply as Region 69), this spot complex has been producing some interesting minor activity in the light of hydrogen (h-alpha). The very large leader spot of this complex should be (or will probably shortly become) an easy naked-eye target for those with appropriate eye protection. The National Solar Observatory imaged this spot complex, shown in-part below as seen in white-light:

Big Bear Solar Observatory was able to obtain a clearer high-resolution white-light image of this spot complex yesterday. It is reproduced below:

The leader umbral spots are encompassed by a large penumbral mass. That penumbral mass (and other nearby penumbral features) also encompass other umbral sunspots of opposite magnetic polarity. Umbral spots (the darkest regions of the sunspots) enclosed within a single penumbra are identified as regions containing what is known as a "delta magnetic configuration." Delta configurations are statistically much more volatile and are more prone to be the sites of major solar flares.

Although Region 69 has been very dormant since it rotated into view about 3 days ago, it may be capable of producing energetic solar flare activity - particularly if new magnetic flux emerges rapidly within the spot complex. At the present time, it is known that this spot complex contains multiple magnetic delta configurations. It has also shown a minor increase in penumbral coverage over the last 24 hours as well as a modest increase in minor flare activity. A major solar flare (possibly multiple major events) from this very large spot complex is certainly very possible as it rotates across the solar disk. However, the observed general quiescent nature of this sunspot complex thus far argues in favor of infrequent and isolated coronal mass ejection activity and/or major flare activity.

Region 69 will remain visible on the solar disk for another 10 or 11 days. As it rotates into a position closer to the central area of the Sun, it will become easier to spot with the naked eye. The best opportunities to observe this spot complex with the protected naked eye will be from roughly the 16th through the 20th of August. This will also coincide with the time the Earth will be the most susceptible to possible coronal mass ejections that may be associated with the passage of this spot complex across the solar disk.

To observe the activity associated with this spot complex in real-time, visit GHAPN (the Global H-Alpha Patrol Network - a professional resource that has been publically available since early 2000). Four major solar observatories are now participating in the patrol network along with one amateur robotic observatory. Big Bear Solar Observatory was the most recent to join network within the last month. When all observatories are on-line and under clear skies, a full 24 hours of continuous solar coverage is possible through GHAPN.

Major Class X4.8 Solar Flare - A Stormy Future

Newly numbered active sunspot complex 10039 rounded the limb of the Sun over the last 24 hours as a fairly complex and moderately large group of sunspots. Big Bear Solar Observatory captured a nice high-resolution image of the spot complex, which is now officially known as active Region 10039 (or Region 39 for short):

The sunspot complex held true to form today by unleashing one of the most powerful solar flares observed in many months, and one of the most impressive events of the solar cycle overall. The class X4.8 solar x-ray flare occurred at 00:35 UTC on 23 July (8:35 pm EDT on 22 July) and lasted about half an hour in x-rays (several hours optically).

The powerful explosion produced a massive chromospheric and coronal wave known as a Moreton wave that propagated at a very high velocity toward the north of the flaring site. The Moreton wave is shown in the sequence of images below. Click on this image itself to play a 239 kilobyte quicktime movie of the event. Imagery again was provided courtesy of Big Bear Solar Observatory.

Moreton waves are relatively rare phenomena in the chromospheric light of hydrogen-alpha that are produced when a fast shock front (from the flare explosion) compresses and heats the matter it passes. They have been observed in h-alpha, extreme ultraviolet (via the SOHO spacecraft where they are more common), and x-rays (the Yohkoh x-ray satellite has on a few occasions detected these events travelling through the higher and hotter coronal regions). Moreton waves in h-alpha often accompany the most powerful solar flares and travel through restricted angles as this one did (there are no readily discernable waves propagating to the south of the flare site).

A high velocity coronal mass ejection accompanied this solar flare. Although the official word on the velocity of this disturbance won't be available until later this UTC day, a very preliminary analysis indicates a velocity perhaps in the neighborhood of 2,000 kilometers per second (very fast!).

The partial halo CME associated with this event may impact the Earth and produce enhanced periods of auroral activity on 24 or 25 July (very preliminary estimates based on incomplete data are hinting at a time late in the UTC day of 24 July [late afternoon on 24 July over North America]).

This solar flare is in all likelihood a proton producing flare. Energetic protons are expected to reach the Earth and begin slowly enhancing the radiation in the near-Earth space environment by the end of this UTC day (23 July). Energetic protons can upset spacecraft by depositing their charge in semiconductors (electronics) in the spacecraft and produce spurious commands (phantom commands) and single event upsets (SEUs). They can also degrade the efficiency that solar arrays generate electricity. If a spacecraft is suffering from low power levels, strong radiation storms can force the premature shut down of the spacecraft.

Astronauts in space are protected in a large measure by the Earth's magnetic field, which redirects most of the energetic protons into the polar regions where they collide with atmospheric constituents and intensely ionize the Earth's lower ionosphere (a phenomenon known as Polar Cap Absorption [PCA]). They are not impervious to the effects of solar radiation storms, however. In low earth orbit, strong solar storms can produce protons capable of penetrating the metal skin of spacecraft. If the proton enters the eye of the astronaut, it can produce flashes of light that are visible whether the eyes are open or shut. A similar effect can be seen in images produced by spacecraft with sensitive 'eyes'. Streaks of light (becoming 'snow' in strong radiation storms) can plague images from spacecraft. Spacecraft that look at the stars to determine their orientation can be confused during such events (the flashes of light from incoming protons may look like stars to the spacecrafts electronics).

Life is not as simple (or as safe) in orbit as it is on the Earth, where almost all of these effects are of no consequence. The only exception may be with passengers on high-altitude aircraft that happen to be flying over the polar regions during very energetic solar radiation storms (where protons greater than 100 MeV are involved). Increased radiation on such flights may expose passengers to the equivalent of a few to several dozen chest x-rays. Some aircraft companies flying these polar routes are preparing for such events, which can be mitigated if the pilot is informed and can reduce altitude. Part of the problem with this is that during strong radiation storms, the ionosphere prevents radio signals from reaching the aircraft if the aircraft is not within line-of-sight of a transmitter. During these intervals pilots must switch to frequencies that allow them to receive transmissions through the ionosphere. But if the ionosphere is flooded with proton-induced ionization, the pilot may be unable to hear alerts to reduce altitude. Careful planning and consultation with space weather forecasters is a good first step to reducing hazards to passengers and crew of high-altitude commercial aircraft.

Additional major X-class solar flares, possible white-light solar flaring, and the effects of these events in the near-Earth space environment over the next two weeks could conceivably produce the most active and geomagnetically stormy conditions the Earth has observed in over 10 years. Whether Region 10039 holds true to its potential depends entirely on whether its structure remains favorable for producing energetic events. And this won't be known for certain until the spot complex is scrutinized for several more days. Until then, we must assume that the spot complex will continue to produce very energetic solar activity about once every 2 to 3 days as it rotates across the face of the Sun.

Region 10039 may well be named a "super region" by the time it exhausts itself if persistence predictions hold true. This spot complex will remain visible for about another 12 to 13 days. It will be well placed for producing large geoeffective impacts on the Earth in just a few more days.

Watch the skies. If activity continues at the pace that has been observed thus far, the next two weeks could see some considerable fire in the skies in the form of solar radiation storms, considerable auroral storm activity, ionospheric storming, and significant geomagnetic storming. Although it's impossible to predict the intensity or spatial extent of visible auroral storming that might occur if flare activity persists, similar historic periods have produced "northern lights" that have been visible throughout the continental United States and Canada and into parts of Mexico and the Carribean, very large portions of Europe and Australia, all of New Zealand and even rare sightings from extreme southern reaches of South Africa and South America. The largest auroral storms on record have produced activity visible from Japan and Hawaii (exceptionally rare events).

By way of interest, studies have shown that very large geomagnetic and auroral storms (known as "superstorms") occur on average once every 6 years or so. It has now been about 12 years since the Earth was hit by a superstorm.

A full discussion of on-going activity is available on our Discussion Forum (free to use - and no signups required).

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Older AstroAlerts

Significant Solar Limb Activity Observed

As noted in the AstroAlert of 19 July, there exists a potential for significant solar activity visible on the east limb of the Sun. Over the last 24 hours, frequent surging has been observed as the strongly active sunspot complex just behind the eastern limb of the Sun begins to rotate into view.

Today, at 21:30 UTC (5:30 pm EDT), a very strong class X3.3 solar x-ray flare was observed from this sunspot complex. Although the sunspot complex itself is not yet visible, the activity it is producing is visible.

Big Bear Solar Observatory (BBSO) was able to cover this event in its entirety (real-time coverage from multiple observatories is also available here). At the peak of the x-ray emissions, a beautifully complex expanding loop prominence became visible. It remained visible for many hours after the flare. An image of this loop prominence from BBSO is shown below. Click on the image itself to download a movie of the event (requires a QuickTime Player).

The bottom portion of the movie shows the solar x-rays as observed by the Geostationary Environment Operational Satellite (GOES).

This spot complex is due to rotate into view within approximately the next 24 to 48 hours. It has been producing energetic solar activity about once every other day during the last week. Until the spot complex rotates into view so we can ascertain it's growth/decay and magnetic characteristics, it is reasonable to assume that this frequency of activity from this spot complex may persist. As a result, this may be one of the best opportunities of the solar cycle to observe energetic limb activity through telescopic equipment equipped with suitable filters.

Frequent surging is expected as this spot complex moves onto the east limb. Limb sprays are possible and post-flare loop prominence arcades are virtually a certainty if this region produces another major flare while near the east limb.

If you don't own a telescope, you can still "observe" these events if you have an inexpensive short wave radio receiver. The intense solar x-rays from these flares are entirely absorbed by the lower layers of the Earth's protective ionosphere (known as the D-region of the ionosphere). During this absorption process, the lower region of the ionosphere becomes much more heavily ionized than normal. Under normal conditions, short wave radio signal energy travels from a transmitter on the ground up to the ionosphere where it is reflected back to the ground a large distance away. During major solar x-ray flares, the lower portion of the ionosphere becomes so heavily ionized that short wave radio signals lose all of their strength when they pass into this intensely ionized region. The result is known as a short wave radio blackout. By listening to radio stations via short wave radio, you can instantaneously detect these strong solar flares by noticing a weakening (or a complete loss) of signal strength. Simple short wave radios capable of receiving broadcasts from popular radio stations such as the Voice of America are inexpensive and can be found at many Electronics stores. You don't even require an elaborate antenna - the one supplied with the radio should suffice in most cases.

A simple short wave radio receiver is capable of detecting minor M-class solar x-ray flares to major M and X-class solar flares. The position of the Sun has a strong bearing on the impact of the signal loss you observe. If the radio signal you are listening to originates from a location that would take the radio signal through sunlit portions of the Earth, you would be able to detect signal loss during solar flare activity. But if the Sun is setting and the radio station you are listening to originates at a location that is still in darkness (further east of you), you won't be able to detect flare activity. So to properly detect solar x-ray flares, you must make certain the radio station you are listening to is either in a sunlit region of the Earth or is transmitting to you through an area of the Earth that is Sunlit. To help you visualize the region that is sunlit, the Space Environment Center makes available a regularly updated (real-time) map that shows the region of the Earth where flare-induced ionization is strong and the radio frequencies that may be affected by the event. The map for today's major X3 solar x-ray flare is shown below:

This map shows that the western U.S. and the Pacific were the hardest hit regions for ionospheric absorption of short wave radio signals. Signals up to 30 MHz were probably affected by this solar flare (you can see from this map how lower frequency radio stations would be affected more than higher frequency stations). Europe, Africa and part of Australia were still in darkness and would not have noticed affects of this solar flare on short wave radio unless they were listening to a radio station that was broadcasting from a sunlit region (short wave radio signals can travel thousands of kilometers).

For those interested in detecting flares using short wave radio, purchase a short wave radio and tune it to stations like the Voice of America . Regularly updated frequency schedules for Voice of America are available here on their web site. Many other stations also exist that would work equally well. Just tune through the bands and find something of interest. If you are in a day lit region of the Earth, the signal is most likely reaching you through an ionospheric bounce and will work well for monitoring solar activity.

Solar x-ray flares more rapidly and more easily affect the lower frequencies below 10 to 15 MHz, so try to find stations below 10 or 15 MHz in frequency if you try this method of detecting flare activity. The length of time that a station remains inaudible during the day reflects the strength and/or duration of the solar x-ray flare. Some significant X-class solar flares in history have produced radio blackouts that have lasted from sunrise to near sunset.

Major Class X1 Solar Flare and CME Alerts

Some exciting and powerful activity is occurring on the Sun. We encourage all solar observers to help in observing the activity.

Mount Wilson Solar Observatory has artistically drawn the two sunspot complexes that have the potential to produce most of the activity at the present time. A source of additional energetic activity may soon rotate into view around the east limb of the Sun.

This is sunspot Region 10030. It has produced several major solar flares. The latest was a class X1.8 solar x-ray flare at 07:44 UTC on 18 July. This event was associated with a fast coronal mass ejection that had an Earthward directed component. This is discussed below.

In approximately 4 days, this spot complex will rotate behind the western limb of the Sun and will be lost from view. It is in a state of gradual decay, but is still quite capable of producing energetic solar flare activity. It was a naked-eye sunspot complex as it rotated through the central solar meridian.

This is sunspot Region 10036. It is located on the eastern side of the Sun and is already identified (by John C. McConnell on 18 July) as a naked-eye sunspot complex. It has not yet produced any significant energetic solar flare activity, but certainly has the potential to do so at any time. It has not yet rotated through the central solar meridian. As a result, this spot complex will remain a good target for protected naked eyes and telescopic observations for some time. It is expected to transit through the central meridian in about 3 days and will remain on the visible side of our Sun for almost another 10 days. It has plenty of time to produce influential levels of solar activity.

Another area of significant interest is an as-yet unseen sunspot complex that is beginning to approach the eastern solar limb. Over the last week or so, this unseen sunspot complex has been responsible for producing some very powerful coronal mass ejections on the back side of the Sun. These coronal mass ejections have been imaged by the Solar and Heliospheric Observatory (SOHO). Some of the mass ejections have been clocked travelling at velocities up to around 1,600 kilometers per second. In layman's language, this is 5.76 million kilometers per hour or 3.6 million miles per hour). Velocities this high are difficult to imagine. To help place this into perspective, if a skilled astronaut could pilot a space vehicle at 1,600 km/sec, he could reach the Sun's surface in a little over one day's time. A trip to the Moon would only take about 4 minutes.

The sunspot complex responsible for these powerful and fast coronal mass ejections is expected to begin rotating into view around the eastern limb of the Sun over the weekend or very early next week. When it does, assuming the spot complex remains as volatile as it has been on the backside of the Sun, we may begin to see additional major solar flare activity.

Amateur solar observers are encouraged to keep a close eye on the eastern limb of the Sun for possible signs of limb-based energetic activity. Those who have H-alpha filters that can be safely viewed through telescopes may witness some exciting activity. Energetic limb activity can produce spectacular surges where mass seems to stream out into space in a beautiful thread-like appearance. Impressive limb sprays where mass from the Sun appears to be suddenly "sprayed" into space are also common with energetic limb activity. Rarer forms of solar prominences can also be observed - for example, loop prominences are often visible in H-alpha following strong solar flares on the limb. These beautiful loops of material can appear very bright against the blackness of space and typically form during and after strong solar flare events (also known as post-flare loops). We encourage amateurs to report any observed and interesting activity to: STD@Spacew.Com. Observations of strong solar flares in H-alpha are also encouraged (please make certain you include the UTC time of your observations and be descriptive with what you see). Observers who are limited to observing the Sun in white-light are encouraged to watch for glimpses of possible white-light flares should solar activity become intense enough to produce such rare events. White light observers should also watch for rapid changes in sunspot structure. Rapid growth and decay often accompany significant solar activity. The appearance of a sunspot complex can change rapidly in just a matter of hours.

Shown above are two closely spaced coronal mass ejections thought to have originated from an unseen sunspot complex behind the east limb of the Sun. The front of each outwardly propagating cloud of mass is identified by the arrow. It is somewhat unusual to see two coronal mass ejections like this within the same field of view and originating (presumeably) from the same active sunspot complex.

The second CME closest to the Sun (which itself is blocked by the black occulting disc of the camera) is travelling faster than the first and will eventually overtake the first while travelling outward through space. Such cannibalistic CMEs can merge to produce complex disturbances that can raise concerns if they impact the Earth. By an interesting coincidence, such a situation presently exists.

On 17 and 18 July, two major solar flares from Region 10030 produced a pair of coronal mass ejections that have the potential of producing periods of active to moderately strong auroral activity on 19 and 20 July. If the two disturbances constructively merge, periods of auroral storm activity may be observed that might produce sporadic episodes of visible activity throughout many dark-sky middle latitude regions. Otherwise, most of the activity may end up remaining confined to the higher latitudes. In response to these events, a Middle Latitude Auroral Activity Watch is being issued for 19 and 20 July. If predictions hold true, activity could begin increasing with the arrival of the disturbances late in the UTC day of 19 July or early on 20 July. For North American observers, this corresponds to the late afternoon and evening hours of Friday, 19 July.

Anyone interested in monitoring the vast resources of images on the Internet are encouraged to download SWIM. A free trial is available here.

Major Class X3 Solar Flare Alert

Confirmed naked-eye active sunspot complex 10030 produced a major class X3 x-ray proton flare on 15 July at 20:08 UTC (4:08 pm EDT). A significant
and fairly high velocity coronal mass ejection was associated with this event. Most of the ejected mass appears to have been directed north and east of the Earth. However, there was a discernable halo in SOHO LASCO imagery, which means at least a portion of the CME is directed Earthward.

This sunspot complex is visible almost in the center of the solar disk as of 16 July. As the days progress, it will gradually rotate toward the western side of the solar disk. It is visible with naked-eye protection and will likely remain visible for the next several days before limb foreshortening takes its toll.

This spot complex has experienced considerable growth over the last few days. Minor decay has been observed in the central portion of the spot complex today, but the more significant trailer portion has continued to grow and maintain a significant degree of magnetic complexity. There are multiple areas of this region where opposite polarity umbrae are enclosed within a single penumbra (a special and often violently unstable magnetic configuration known as a "delta"). This may aid in the development of additional energetic solar flare events from this spot complex.

Should additional significant activity occur, there is a high probability the near-Earth space environment would be bathed in streams of energetic solar protons. Although these energetic particles can pose a health risk to astronauts in orbit, they often pose a greater challenge to spacecraft in higher or transpolar orbits where energetic proton densities can become significant enough to produce spurious anomalies and phantom commands on these spacecraft. These space radiation storms do not pose a health hazard to humans on the Earth. The Earth's magnetosphere and ionosphere do a marvelous job shielding us from harmful effects.

Solar observers are encouraged to keep a close eye on this spot complex for possible white-light solar flare activity. Please report any confirmed white-light flare sightings to: STD@Spacew.Com (if possible, please include an image of the event to help confirmation). Pay particular attention to the trailer portion of the spot complex.

The ejected mass from the 15 July energetic coronal mass ejection is expected to impact the Earth sometime on 17 July and persist through at least part of 18 July. Periods of minor to major auroral substorm activity may develop in association with this CME impact. Widespread middle latitude observations of auroral activity may be possible on these dates.

The activity most likely will not be as strong as the events following the famous Bastille Day flare on 14 July 2000 (which occurred in a spot complex not too dissimilar from the current sunspot complex). However, the potential exists for occasional respectable levels of activity. Whether a specific region (i.e. "your region") observes auroral activity is very heavily dependent upon when the disturbance arrives and whether "your" region is on the dark side of the Earth or not. Your best chances are to stay informed over the coming days. Current and updated conditions are made available at: http://www.spacew.com/aurora/forum.html (in particular, refer to the current forecast conditions at the bottom of this page).

Possible Naked Eye Sunspot Complex

A large and potentially active sunspot complex rotated into view around the south-eastern limb of the Sun on 27 May. This sunspot complex, identified as active sunspot Region 9973, currently measures 960 millionths of the solar hemisphere. This is large enough to completely map a little more than five and half times the entire surface area of the Earth into the sunspot complex. It may be large enough to spot with the protected naked eye (never look at the sun directly without protection - doing so could permanently damage your eyes!). Only use solar filter's approved for observing the Sun. Don't experiment with your sight!

The sunspot complex in question is visible in the southeast quadrant of the Sun (the bottom-left side in the image above). It appears to be moderately complex magnetically and may support energetic solar flaring. It is still a little too close to the solar limb to discern any significant detail. However, the size of this spot complex alone is enough to raise some concerns.

This sunspot complex will be easier to view with the protected naked eye about 2 or 3 days from now and will remain optimally placed for naked-eye observations for about an additional 4 days thereafter (5 or 6 days from now) as the spot complex rotates from east to west.

If this spot complex begins to produce energetic solar flare activity, the potential for middle latitude sightings of auroral activity may also increase over the next week or two.

Earthward-Directed Coronal Mass Ejection Alert / Middle Latitude Auroral Activity WATCH

A long-duration solar flare from active sunspot Region 9906 was observed at 03:55 UTC on 15 April (11:55 pm EDT on 14 April) that was associated with a near-symmetrical full-halo coronal mass ejection. The event was observed by the SOHO spacecrafts LASCO instrument. The following two images depict the ejected mass as it is ejected toward the Earth as a halo of light surrounding the occulting disk of the LASCO instrument.

The expanding cloud of mass can be clearly seen in this sequence of images obtained by "differencing" the LASCO images which detects subtle changes and faint features of mass ejections.

This coronal mass ejection is expected to impact the Earth's magnetosphere sometime during the latter part of the UTC day of 17 April (the afternoon hours of 17 April for North American observers or the late evening/early morning hours of 17/18 April for European observers). This disturbance has the potential to produce periods of minor auroral activity that may become visible over some high and upper-middle latitude regions (areas near the U.S. / Canada border or extreme northern regions of Europe). The near-new phase of the moon will provide optimally dark skies for observing potential activity. Observers equipped with cameras are encouraged to take snap-shots of the horizon after this disturbance impacts, even if activity is not observed with the unaided eye. Cameras are much more sensitive to light than human eyes are and are often capable of imaging the diffuse glows of auroral activity that the eyes cannot detect. Longer duration exposures are recommended if activity is not visible to the unaided eye. ASA 400 to 800 film is recommended. Additional recommendations from experienced auroral photographers can be found by visiting our discussion forum.

Although this disturbance probably will not be particularly strong, it may have the potential to produce periods of localized intense activity. Observers are encouraged to watch for possible periods of visible activity on 17 through 19 April. For North American observers, the evening and early morning hours of 17/18 April should be the best times to watch for activity. European observers should watch for activity during the early morning hours of 18 April and again during the evening hours of 19 April. Activity probably will not be visible to North Americans during the evening of 19 April unless additional coronal mass ejections are thrown Earthward.

Potential Major Solar Flare Warning Issued

As of 15 April, solar observers have kept a close eye on a sunspot complex that has experienced rapid growth and a notable increase in magnetic complexity over the last several days. Forecasters suggest there is a very real possibility this spot complex may spawn a major solar flare over the coming days. It has already produced some moderately impressive longer-duration minor solar flare activity and may be poised to produce a more energetic outburst as it rotates into the western solar hemisphere. Since major solar flare events are often associated with influential coronal mass ejections, people interested in watching for auroral activity ("northern lights") are also in a "state of readiness" for possible energetic activity that might issue forth from this spot complex.

The sunspot complex of concern is identified as active Region 9906, and is depicted in the "white-light" image below (courtesy of SOHO):

There is a notable potential for major M and/or X class solar x-ray flares from this active sunspot complex. A significant east-west oriented neutral line has formed (most are in a more stable north-south orientation) within this spot complex. It also harbors a more complex magnetic delta configuration where two opposite polarity umbral spots are present within a single penumbral region. This particular type of configuration is less stable and more prone to energetic flare activity. With continuing growth evident within this spot complex, concern is increasing that more energetic activity may soon be observed.

Observers interested in the surveilance of this (and other potential) activity may find the software available here of considerable interest.

Severe Geomagnetic Storm Intervals in History
And Future Prospects

Comparison of sunspot numbers and severe storm events

As we proceed through the decline of the current solar cycle, a popular opinion seems to have arisen with the media and others that geomagnetic activity and auroral activity ("northern / southern lights") will begin to subside ever increasingly (if not halt altogether). We present the plot above in order to bring some truth to this myth.

The plot above shows the last six solar cycles and our progress through the current solar cycle (cycle number 23). The smoothed monthly sunspot numbers for each month since 1932 are shown as a series of interconnected (small) black dots. This plot line is extended at the end using the color green to depict the predicted behavior of sunspot numbers through to the next solar minimum (which is currently expected to occur in late 2006). Our current stage in the solar cycle (as of March/April 2002) is the location in the graph where the black and green plot lines intersect.

Superimposed on this plot are red dots that represent the months during each solar cycle where at least one or more severe geomagnetic storm intervals occurred (where the planetary Kp index reached at least 8 - Kp indices are rated from 0 [dead quiet] to 9 [extremely disturbed storm conditions]). Such high Kp indices are typically only observed during major to severe geomagnetic storms and they are often associated with significant sightings of auroral activity across the world.

The blue dots are identical to the red dots except that they are plotted horizontally. This is done to retain perspective. Since the horizontal axis of the chart has much higher resolution than the vertical axis, dots that appear near the solar maximums may appear (falsely) to be more numerous than during the decline of the solar cycles because the red dots are spaced closer together. This illusion largely disappears when you examine the blue dots.

The chart portrays the fact that severe geomagnetic and auroral storm intervals can occur at almost any time during the solar cycle, but there is a slightly heavier preference for the years around the solar maximum and during the declining years of the solar cycle. Intervals of severe activity are less frequent during the years immediately around the solar minimum and during the ascending years of the sunspot cycle.

By comparing our current position in the solar cycle with similar positions in the last 6 solar cycles, it becomes clear that we are perhaps only about half way through the interval where severe space weather storms occur most frequently during the solar cycle. In fact, we are just barely beginning to see the real decline in this cycles sunspot numbers (most solar maximums have a fairly lengthy plateau of several years and we are just barely at the end of this plateau).

Historically, some of the most intense geomagnetic and auroral storms have occurred during the declining years of the solar cycle. For example, the most severe geomagnetic storm on record occurred on 17 September 1941. That was 53 months after the solar maximum! To place this into better perspective, the Sun is currently in about its 23rd post-solar maximum month (solar maximum occurred about 23 months ago). In fact, this 1941 storm occurred during a time when the sun was closer to the solar minimum than the solar maximum. Severe geomagnetic storms have also occurred within just a few months of the Sun's actual solar minimum as well, which confirms the fact that significant space weather activity can occur at any time during the solar cycle.

We hope that this information will help dispell the popular myth that geomagnetic and auroral storm activity on the Earth will stop now that we have passed the solar maximum. This couldn't be further from the truth. Statistically, the declining years of the solar cycle are the most stormy in terms of geomagnetic and auroral activity.

It is safe to say that we can expect at least several more years of potentially violent space weather activity.

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