Celebrate Solstice 2024 with a Solar Fireworks Show!

Today is the Summer Solstice, the longest day in the Northern hemisphere and the shortest day in the Southern. That officially happens at 20:50 UTC (4:50 pm ET). This solstice is the first day of summer in the USA.

But it has nothing to do with the Sun. The solstice is caused by the tilt of the Earth’s rotation axis to its orbit. On the other hand, we are in the maximum of Solar Cycle 25. Active region 13664 was an excellent example of how an active region should behave during a solar maximum. During the 16 days that AR 13664 was visible from the Earth in May, it produced 99 flares, including 12 X-class flares.

I produced a video of AR 13664 to celebrate the solstice. I downloaded three-color AIA images from the SDO website AIA and GOES XRS fluxes from the GOES website for days between 01 May 2024 and 16 May 2024. After removing the blank and offset images taken during an EVE cruciform, there were 1522 valid images in those 16 days (99% of the possible 15-min images). The XRS flux had 21616 points that were greater than zero.

Using the JythonMusic synthesizer, the XRS fluxes were converted to MIDI percussion sounds and then into a mp4 file. There’s a lot of different drums and cymbals in the soundtrack. XRS fluxes below a C-class flare were made into rests. When the video is quiet the Sun’s activity level is low.

The AIA images and audio file were combined to give the Solstice Celebration Video shown here.

The video starts with sporadic flares and some visible activity. Once AR 13664 starts generating flares the sound and images quickly start to resemble a fireworks finale! As AR 13664 rotates out of view the activity level drops, even though new active regions have appeared. You can also see a few non-solar things, such as the apparent rotation during a calibration roll maneuver. The flare sounds and flares in the images are not exactly in synch as the images are not frequent enough.

The solar fireworks were only the beginning. The largest geomagnetic storm in over 20 years took place on 11 May 2024. It's nice to see some geomagnetic activity after the storm-poor Solar Cycle 24. Large solar and geomagnetic activity makes it more difficult to track satellites in low-Earth orbit to keep them from colliding but that’s why we study the Sun.

AR 13664 was a fascinating feature of Solar Cycle 25!

An X1.3 Flare and a Cool View of Plasma Leaving the Sun

On March 30, 2022, active region 12975 was the site of an X1.3 flare. Here is the daily movie in AIA 171 from that day. AR 12975 is in the upper right quadrant to the right of the far more impressive looking coronal loops above AR 12976.

During the day we adjusted the fine guidance telescope, which causes the images to bounce a little bit. The flare starts at 17:26 UTC and ends at 17:46 UTC. What I found cool about this flare was the lass of plasma just south of the flare site. Here are two stills from the movie.

On the left the arrow points at some haze in the AIA 171 image. In the right image the arrow points at about the same place (there is a bright streak just to the right to get you oriented), but the image is less hazy where plasma has left the Sun.

The material that left the Sun isn't all that close to the flare. But you can see in the movie that the haze goes away just after the flare. Look at the movie a few times and you will see the haze disappear.

There is also an excellent coronal cavity display at about 4 o'clock on the limb. These cavities are usually much slower in their evolution.

It is already a great Solar Cycle!

X-class flare at 1555 UTC (11:55 am ET)

Active region 12887 emitted an X-class flare today at 1555 UTC. There also appears to be a filament eruption (the precursor to a coronal mass ejection). This is the second X-class flare of Solar Cycle 25 (the first was on July 3, 2021.)

Before the flare a filament cam be seen over AR 12887 (in the blue circle).

The flare begins to brighten up at 1529 UTC.

The filament liftoff from the surface can be seen as the dark region a litle to the left of the flare in the third image.

The flare continues to brighten until its peak flux. Check out the flare in the Browse AIA/HMI Images at the SDO website.
Solar Cycle 25 is alive and well!

Some Fireworks over the Weekend!

At 1430 UTC (10:30 am ET) on July 3, 2021, the first X-class flare (actually an X1.5 flare) of Solar Cycle 25 was seen on the Sun.

There were also several B and C flares, and even one M flare in the day before the X1.5 flare. You can see this series near the limb in the upper right (a clock position of about 2:00) in this daily movie in SDO's AIA 94 Å passband. These flares were also seen in the EVE on SDO and the XRS on GOES-16.

There was no active region associated with the X1.5 flare. A large region of magnetic field that was rotating off the disk is probably the home of the flares.

Solar Cycle 25 is starting to get more interesting!

Nice Video of Solar Cycle 24 Eruptions

Can't get enough solar eruptions, especially from SDO? Here's a nice video from the Solar-Terrestrial Center of Excellence in Brussels, Belgium. They call it Spectacular Solar Eruptions during Solar Cycle 24. Many of my favorite eruptions are included, along with others that might become your favorite. Videos from STEREO, SOHO, and Proba2 are also included.

Enjoy!

A Flare, A CME, A Storm!

Yesterday we saw an M6.5 flare from active region 12372 followed by a filament liftoff, which turned into a coronal mass ejection, which became a a strong geomagnetic storm. Here are the NASA iSWA Kp values for the last four to show you how the Earth responded to the CME. Kp is a measure of the magnetic storm intensity, averaged over the many stations that measure the Earth's magnetic field. The NOAA SWPC has issued a G2 alert for today, meaning moderate storm activity should continue. The Kp index is described at the Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences.
Soon after the flare, another filament rose off the surface. It will probably strike the Earth's magnetosphere tomorrow (June 24). This means the geomagnetic storm will continue for awhile. Great aurora come from these storms, but they also produce energetic particles and currents in ground-based pipelines and electrical wires.
Welcome to the declining phase of Solar Cycle 24!

The First X-class Flare of 2015!

Active Region 12297 was the site of two M-class flares yesterday and an X2.1 starting today at 1611 UTC (12:11 p.m. ET). AR 12297 is in the southern hemisphere of the Sun. This movie in the AIA 304 Å shows about 90 minutes of time that includes the flare. Note the ribbon of material that lifts off the surface. 

Check Out the Flares

Monica Bobra of Stanford University and Chau Dang of Scientific American published a blog article about flares seen by SDO.

You can see where the flares happened and look at the details of each flare.

One of our goals with SDO is to be able to predict all kinds of solar activity. It's not as easy as you think. Monica Bobra is developing ways to predict when flares will occur. The blog article talks about using machine learning methods for these predictions.

Check it out!

It's Coming Around Again!

Active Region 12192, which was the location of 6 X-class and several M-class flares in late October, is coming back for an encore. Here is a movie of the Sun showing the magnetic field on the side facing the Earth and the farside image from HMI data. It shows the part of the Sun containing AR 12192 rotating back into view, with a large magnetic feature still there.
These composite maps of the Sun’s farside (in yellow) and the line-of-sight magnetic field (blue) show NOAA AR12192 as a bight-dark magnetic feature rotating out of view over the west limb at the beginning, passing the far-side meridian in the middle as a dark area, and approaching the east limb at the end. The farside information is shown as the travel time change in the echo produced by a strong magnetic region.

This farside images allow us to track magnetic features where SDO cannot see. They have been compared with the full-Sun images we make by combining SDO and STEREO images. When AR 12192 returns it will have a new number but we hope it will be just as active.

Many thanks to the HMI team for producing these images and movies. They are available at JSOC.

What an Active Region!

What an active region 12192 has been! Six X-class flares in 9 days. Here is an HMI image of AR 12192 at 1615 UTC on 23-Oct-2014. You can see a couple light bridges going across the sunspots. There are some partial bridges in the left hand sunspot. But no matter how hard I squint I can't see a jack-o-lantern. It will soon be lost to view as it rotates over the limb of the Sun. Large flares often (but not always) come from large active regions. How did AR 12192 rank in size among active regions?

I downloaded the active region dataset produced by David Hathaway at Marshall SFC and looked at the largest active regions since 1874. This area data comes from the photographs taken at the Royal Greenwich Observatory until 1976 and various sources after that. I checked the list against the tables in Sunspot and Geomagnetic-Storm Data by Sir H. Spencer Jones just to make sure. I also added two regions from 2014 (AR 12192, of course, and AR 11967). Areas of active regions are measured in micro-hems (millionths of a solar hemisphere, where 1 micro-hem is about 1.54 million sq km.)

Here is the plot of maximum area of active regions in time. There are 32908 active regions in this plot. The color and symbol size changes as the area increases. AR 12192 is drawn as a black dot all the way at the right side of the plot. There is a dashed line drawn at 2750 micro-hems to help you compare this area with the others. From this we see that AR 12192 ranks 33rd in a list of active region sizes, not the biggest but in the top 0.1%. It is bracketed by AR 4497 on 08-Jan-1897 (2743 micro-hems) and AR 19109 on 08-Jan-1959 (2805 micro-hems). The area of the Earth is 83 micro-hems, meaning AR 12192 has an area of about 33 Earths.

The yearly Sunspot Number is drawn as a red line. This allows you compare how the maximum area of active regions changes with the number of active regions. It was surprising that the largest active regions are not in Solar Cycle 19, which has the largest amplitude in Sunspot Number, but in Solar Cycle 18. The top 5 active regions appeared between 1946 and 1951. Solar Cycle 19 started in 1954. The next set of large active regions have areas of 3000-4000 micro-hems and are spread across many sunspot cycles.

How big was the active region that was the site of the Carrington Flare? It was 2300 micro-hems, not even in the top 50! You can look it up on p. 102 of the table by Jones. The flare on 1-Sep-1859 has been estimated at X35, showing that large flares can come from medium-sized active regions.

So long for now to AR 12192 but perhaps we will see you next rotation!

It's Flare Season!

Active Region 12192 has grown to 2410 millionths of a solar hemisphere (0.2410 % of one side of the Sun), making it one of the larger active regions in Solar Cycle 24. It unleashed an X1.6 solar flare at 1400 UTC (10:00 am ET) today. Here is an HMI continuum, image with the visible active regions labeled. It had already been the site of several M flares and a half dozen C flares. This pattern of large active regions (and large flares) is common for Solar Cycles. Some of the largest flares ever recorded were in the later stages of Solar Cycle 23, and were also in the southern hemisphere of the Sun. I have been told AR 12192 is visible to a well-protected eye without a telescope. The rain in the Mid-Atlantic will prevent me from testing that, but others can check that out. (Always use appropriate eye protection when looking at the Sun! Eclipse glasses or other tested and approved filters should be used.)

This active region has caused a "Major Flare Watch" to be declared, so the two calibration maneuvers SDO had scheduled for today will be done in two weeks. Here is a summary of our projected activities for the rest of 2014.

• 10/20/2014: Null Bias Application
• 10/29/2014: EVE Cruciform (@1800ut)
• 10/30/2014: Null Bias Removal
• 11/05/2014: EVE FOV (1315-1537 UTC) and HMI/AIA Flatfield (1630-1907 UTC) Calibration Maneuvers
• 11/12/2014: Null Bias Application
• 11/22/2014: Lunar Transit (2229-2304 UTC)
• 12/01/2014: Null Bias Removal

Stationkeeping Burn #9 and an X1.6 Flare

Stationkeeping burn #9 will happen today (September 10, 2014) at 2215 UTC (6:15 p.m. ET). SDO data will be unavailable for about 30 minutes starting 2200 UTC (6:00 p.m. ET). This burn was delayed from last Wednesday when we became concerned about another satellite whose orbit would have come close to SDO after the burn.

Today the sun let loose a X1.6 flare, starting at 1721 and peaking at 1745 UTC.

Solar Dynamics Observatory Captures Images of a Late Summer Flare

On Aug. 24, 2014, the sun emitted a mid-level solar flare, peaking at 8:16 a.m. EDT. NASA's Solar Dynamics Observatory captured images of the flare, which erupted on the left side of the sun. Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground, however -- when intense enough -- they can disturb the atmosphere in the layer where GPS and communications signals travel. This flare is classified as an M5 flare. M-class flares are ten times less powerful than the most intense flares, called X-class flares.

Image Credit: NASA/SDO

Another Double Whammy from Active Region 12087!

Active Region 12087 rotated into view yesterday and produced 2 X-class flares. This morning it produced an M8 and an X1 flare about an hour apart. Here is an AIA 94 Å passband image from 0914 today showing the second flare. At the same time the AR 12080/12085 area also had a brightening (as can be seen by the vertical line in this image) and a small piece of AR 12082 also brightened.

Makes you want to get up early in the morning just to see what's happening on the Sun!

Great Day in the Mornin', A Double X-flare

This morning a new active region rotated into view on the solar disk and promptly emitted two X-class flares. Here is a movie of the first flare in the AIA 1600 passband. It peaked in the NOAA X-ray channel at 1142 UTC. You can see the flare and some footpoints down and to the right of the flare. You can also see material blowing off the sun. The geometric shapes that are visible during the peak of the flare are reflections of the front window of the telescope. 

It's going to be an interesting week on the Sun!

X-class Solar Flares from Space and the Ground!

Wondering what else we need to know to understand X-class solar flares? Join SDO and others on a Google+ Hangout today at 2:30 pm ET. We will describe an X1 flare that happened 29-Mar-2014. It was the first X flare observed by IRIS and was also seen by SDO, SoHO, Hinode, RHESSI, and the Dunn Solar Telescope in New Mexico. When IRIS watches a solar flare it can measure how fast the plasma is moving, a huge clue to how flares work. This flare produced a nice coronal dimming going over the pole that was described in an earlier blog post.

The Hangout URL is: https://plus.google.com/events/c99gnf2e4l9vb4n6logpsemkhlo, staring at 2:30 pm ET and going aboit an hour.

CNN featured a picture of the March 29 flare in Pictures of the Week!

Whoa, an X4.9 Flare!

This morning the Sun released an X4.9 flare from AR 11990 at 13 S, 78 E on the solar disk. It can be seen in this AIA 94 image as the bright area on the left of the image. It appears that there is a filament leaving the Sun as well in this image from 0047 UTC.

The flare lasted from 0039 UTC until 0103 UTC. The area of impact would be the sunlit side of Earth, with the greatest effects at the sub-solar point. Any coronal mass ejection from this location is unlikely to hit the Earth but might be measured by the STEREO spacecraft.

A Lunar Transit

Today the Moon passed between SDO and the Sun from 1331-1556 UTC (8:31-1056 am ET). At 2.5 hours in length, it was the longest lunar transit so far in the SDO mission.

You can watch the transit using the browse data option on our website. Use the times 2014-01-30 00:00:00 and 2014-01-30 17:00:00 and your favorite wavelength to enjoy the show.

Here is an image from 2014-01-30 14:29:12 in the AIA 171 passband. If you watch the movie you will see the Sun move a little bit during the transit. This transit covers a lot of the solar disk and blocks the sunlight from SDO. The fine guidance systems on AIA and HMI can't work because they need to see the whole Sun to keep the images centered from exposure to exposure. Once the transit is over the fine guidance systems started back up, giving us steady images of Sun.

And, as the Moon left SDO's field of view, an M8 flare erupted in AR 11967.

AR 11893 Waves Goodbye with an X-1 Flare

As AR 11893 rotates over the limb of the Sun it erupted with a X-1 flare at 1030 UTC (5:30 am ET) this morning. Here is a detail from the AIA 1700 Å channel. This image was taken at 5:32:55 am ET this morning. It shows a graceful arch where the flare is occurring. The AIA 1700 Å channel is sensitive mostly to ultraviolet continuum light, but during a flare some hot lines are seen. You can see details about the flare without the blooming seen in the hotter channels.

Another X-class flare!

Active region 11875 let loose an X2.3 flare. Strong radio emissions were also measured during this flare. The flare started at 2142 UT (5:42 pm ET) and lasted about 20 minutes. The active region is on the limb (edge) and it rotating out of sight from SDO.