Two weeks in the life of a sunspot


Release: 4-Aug-2017

From Eurekalert               

NASA/Goddard Space Flight Center

On July 5, 2017, NASA’s Solar Dynamics Observatory

watched an active region — an area of intense and complex magnetic fields —

rotate into view on the Sun. The satellite continued to track the region as it

grew and eventually rotated across the Sun and out of view on July 17.

With their complex magnetic fields, sunspots are often

the source of interesting solar activity:

During its 13-day trip across the face of the Sun, the

active region — dubbed AR12665 — put on a show for NASA’s Sun-watching

satellites, producing several solar flares, a coronal mass ejection and a solar

energetic particle event. Watch the video below to learn how NASA’s satellites

tracked the sunspot over the course of these two weeks.

Such sunspots are a common occurrence on the Sun, but

less frequent at the moment, as the Sun is moving steadily toward a period of

lower solar activity called solar minimum — a regular occurrence during its

approximately 11-year cycle. Scientists track such spots because they can help

provide information about the Sun’s inner workings. Space weather centers, such

as NOAA’s Space Weather Prediction Center, also monitor these spots to provide

advance warning, if needed, of the radiation bursts being sent toward Earth,

which can impact our satellites and radio communications.

On July 9, a medium-sized flare burst from the sunspot,

peaking at 11:18 a.m. EDT. Solar flares are explosions on the Sun that send

energy, light and high-speed particles out into space — much like how

earthquakes have a Richter scale to describe their strength, solar flares are

also categorized according to their intensity. This flare was categorized as an

M1. M-class flares are a tenth the size of the most intense flares, the X-class

flares. The number provides more information about its strength: An M2 is twice

as intense as an M1, an M3 is three times as intense and so on.

Days later, on July 14, a second medium-sized, M2 flare

erupted from the Sun. The second flare was long-lived, peaking at 10:09 a.m. EDT

and lasting over two hours.

This was accompanied by another kind of solar explosion

called a coronal mass ejection, or CME. Solar flares are often associated with

CMEs — giant clouds of solar material and energy. NASA’s Solar and Heliospheric

Observatory, or SOHO, saw the CME at 9:36 a.m. EDT leaving the Sun at speeds of

620 miles per second and eventually slowing to 466 miles per second.

Following the CME, the turbulent active region also

emitted a flurry of high-speed protons, known as a solar energetic particle

event, at 12:45 p.m. EDT.

Research scientists at the Community Coordinated

Modeling Center — located at NASA’s Goddard Space Flight Center in Greenbelt,

Maryland — used these spacecraft observations as input for their simulations of

space weather throughout the solar system. Using a model called ENLIL, they are

able to map out and predict whether the solar storm will impact our instruments

and spacecraft, and send alerts to NASA mission operators if


By the time the CME made contact with Earth’s magnetic

field on July 16, the sunspot’s journey across the Sun was almost complete. As

for the solar storm, it took this massive cloud of solar material two days to

travel 93 million miles to Earth, where it caused charged particles to stream

down Earth’s magnetic poles, sparking enhanced aurora.


Disclaimer: AAAS and EurekAlert! are not responsible for the

accuracy of news releases posted to EurekAlert! by contributing institutions or

for the use of any information through the EurekAlert system.

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Patrick MJD
August 6, 2017 5:40 am

I remember when I was 8 and studying this, in primary school, in the UK. I was also pulled up in front of class by class teacher, Mr. Harris, for doodling during end of class story telling. I was doodling a solar flare and had to explain what the doodle was. Mr.Harris, for all he was good at, had no idea what the doodle was.

August 6, 2017 5:41 am

Funny, I thought I was the only one spending time watching stuff on SDO! Here is a good write up and imagery from IRIS,

Pop Piasa
Reply to  2hotel9
August 7, 2017 10:57 am

Here’s the next week or so in the life of that AR as viewed from STEREO-A coronagraphs:

Reply to  Pop Piasa
August 7, 2017 4:19 pm

Real shame that Stereo B had technical issues and dropped out.

Pop Piasa
Reply to  Pop Piasa
August 7, 2017 6:51 pm

No doubt, stereo imaging from A’s original position would have been great for the double CME.

Tom Halla
August 6, 2017 5:56 am

it is good to see NASA doing astronomy rather than Muslim outreach.

Reply to  Tom Halla
August 6, 2017 6:36 am

There is actual science being done in NASA, underneath the politically driven climate data tampering and social justice virtue signalling. Cassini has produced a wealth information and some damned good imagery,
Hinode is getting some excellent work done, though this link is kinda wonky, took 4 tries to load.

Javert Chip
Reply to  Tom Halla
August 6, 2017 4:30 pm

Hated to see Obama hang USMC Major General Charles Bolden (ret), a Marine fighter pilot & combat veteran, out to dry with that dumb mission statement.
Bolden bore some of the blame for letting himself get used like that, but he gets a lot of forgiveness.

August 6, 2017 6:05 am

I remember when I was a kid being pulled out of bed by my dad so I could see the aurora happening outside. What was unusual was that it was the middle of July and even though we were at the 44th parallel the aurora it was right overhead. It was astonishing.
My dad told me to remember the event because I would likely never see it again in my lifetime. It’s been 50 years now and so far he’s right.

Reply to  Klem
August 6, 2017 6:37 am

That’s great. Thanks for sharing it with us. I have never seen an Aurora, but I have seen a total eclipse of the Sun as will many very fortunate Americans on the 21st.

Crispin in Waterloo but really in Ulaanbaatar
Reply to  Klem
August 6, 2017 7:40 am

I was on the roof of Rochdale College on that night, watching the cartoon version of Animal Farm under the sky. It was an amazing night and I have not seen one like it since.
Comparable for spectacle, however, is a cold summer night in Mongolia. The air is so clear that one can see 100 times more stars than can be imagined. Absolutely beautiful.

Reply to  Klem
August 6, 2017 7:52 am

I was witness to an aurora borealis event only one time.
I was a member of a “big game” hunting party in the northern British Columbia “bush” and awoke one early morning about 3 AM with a dire urge to go “wee wee”. So I stepped out of the tent-frame, still half asleep, and while relieving myself I glanced up in the clear night sky ……. and temporarily got the bejesus scared out of myself.
Those eerily green n’ blueish lights were prancing and dancing all over the sky above me and moving so damn quick I just knew it was my imagination “playing tricks” on my good senses.
It must have taken me 15 seconds before I became wide awake and realized what I was seeing, which was then that I exclaimed, …… “Holy Cow, those are the honest to goodness Northern Lights that I have been reading about and studying for all these past years”.
A truly amazing sight when you witness them the 1st time.

John Harmsworth
Reply to  Samuel C Cogar
August 6, 2017 8:29 am

Living in Southern Canada in a rural area I have seen them dozens of times. It never gets old. Light pollution obscures them for many millions unfortunately.

Reply to  Samuel C Cogar
August 6, 2017 3:37 pm

I saw one stunning display in October 1972.
We had berthed in Svolvaer. I walked a local young lady home.
Just before her house, we stopped. and then the Aurora started.
I can’t now remember how long – but possibly ‘half an hour’ [IIRC].
At the conclusion she said it was the finest display she had ever seen, kissed me quickly, then went in.
I made my solo way back to my ship – ‘British Cormorant’, Master Jimmy Gillan – and wrote to the young lady for a year or more.
Ahhh. Young Lust!

Reply to  Klem
August 6, 2017 7:58 am

I am also on the 44th parallel and recall a very bright aurora about 16 or 17 years ago but it was not overhead, probably 25 to 30 degrees above the northern horizon. Unfortunately, I did not record the date though it was in the fall as we were returning from one of our boys’ football games on a long drive north headed home between 11 pm and 12 am. A memorable sight!

Reply to  Klem
August 6, 2017 12:05 pm

What was unusual about its occurring in the middle of July? Aren’t there equal chances of aurorae in all parts of the year? Sure, nighttime is shorter in summer, but during any given nighttime hours, the chances should be equal all year long.

Reply to  Klem
August 6, 2017 2:48 pm

A night to remember that happen for me was in July of 2014. When northern England was treated to a display of night shinning cloud that was a match for any Aurora display. lt was 3am in the morning and l was working a nightshift. The display covered about a quarter of the northern sky with swirls and twirls of bright sliver blue clouds. While lower down in the sky where the cloud became thicker and was in layers it then became white and then in places turning to yellow and red. Never seen anything like it in my life.

August 6, 2017 6:18 am

Cool stuff. 🙂

Larry Vaughn
August 6, 2017 6:56 am

As an Air Force Navigator, I have 50 missions over the North Pole. One mission there was Saint Elmo fire dancing on our wings and a plasma ball formed in the cockpit and then rolled down the walk way into the wing root. We did not detect and instrument problems. That was seeing the aruora up close and personal.

Reply to  Larry Vaughn
August 6, 2017 2:45 pm

Flying a P-3 through a thunderstorm at night, we’d get a lot of St. Elmo’s fire. The props would glow, any metal outside the windshield would glow with electrical discharges, the radios would be completely useless from the static noise–even the VHFs, and occasionally an electrical, lightning-like streak would flash across the windshield. The windshields were conductive and were heated to make them less brittle. I never saw ball lightning though.

August 6, 2017 7:22 am

The initial photo on the home page, with multiple large sunspots, is misleading. Right now there is one sunspot visible:
Otherwise, it is a great post…

Reply to  J. Philip Peterson
August 6, 2017 8:12 am

That is the same sun spot, next time around. They do not “disappear” when they roll around the back. SOHO can still pick them up. They still exist and come back 13d later.

Reply to  Greg
August 6, 2017 8:26 am

Agree, I was thinking that might be the same sunspot which has come back around…

Reply to  Greg
August 7, 2017 3:24 am

I have actually had people, with supposed educations, argue that the Sun does not rotate it only appears to because the Earth moves around the Sun. One even called me a flatearther because I “believed” the Sun spins. Yes, they are true believers and faithful followers of Brother Al Gore.

Pop Piasa
Reply to  Greg
August 7, 2017 5:04 pm

Actually, Greg it’s STEREO-A that “sees” the far side (in solitude until STEREO-B is recovered).

Reply to  J. Philip Peterson
August 6, 2017 7:15 pm

That image was taken in 2003:

Richard M
August 6, 2017 7:59 am

As I have mentioned previously it is not unusual to see a bump up in daily satellite temperatures whenever we have a CME. If you look at the UAH daily value we see another example of this in July. The warming usually lasts 5-10 days before falling back down.
This is one way fewer sunspots/CMEs could affect our temperature. I have no idea why this happens and what the mechanism might be. Just something I have noticed.

Reply to  Richard M
August 6, 2017 8:25 am

I only get a black graph from that link, there does not seem to be any data for ch04 and 05. Where is the “spike” you are seeing?

Richard M
Reply to  Greg
August 6, 2017 10:56 am


Reply to  Richard M
August 6, 2017 11:34 am

Richard M – What you describe sounds like the effect of a Forbush Decrease. A CME causes a drop in GCRs (Galactic Cosmic Rays) which causes a decrease in cloud cover. Max Temp goes up, but Min Temp goes down. Please look for ‘Forbush’ in

August 6, 2017 8:01 am

Here is a good site link to complement this post. There are a bunch of links at the bottom of the page to deeper sites if interested.

michael hart
August 6, 2017 10:53 am

Is it though they ever last long enough to come around again for a second viewing?

michael hart
Reply to  michael hart
August 6, 2017 10:57 am

spelling “thought”
I also recall once reading something about a triple-satellite system that could observe the sun from the other side. Is there such a system?

Pop Piasa
Reply to  michael hart
August 7, 2017 5:36 pm

STEREO-A shows the far side by itself after its B counterpart failed.
“Communications with Solar Terrestrial Relations Observatory-B (STEREO-B) were lost on Oct. 1, 2014, due to multiple hardware anomalies affecting control of the spacecraft orientation.”
The STEREO satellites combined with SOHO or SDO nearside images would provide a 3-point 360 of Sol, with stereo imagery of the occulted events.

August 6, 2017 11:39 am

…and in other bigly news….just so no one misses it……..the BoM has got a lot of ‘splaining to do
(tips must be full, won’t open for me……yes, eventually I need a new puter)

Roger Knights
Reply to  Latitude
August 6, 2017 3:29 pm

Jo Nova’s site is on top of this OZ BOM scandal with five recent stories on it at

August 6, 2017 6:17 pm

Our esteemed visitor, Leif Svalgaard, has done tremendous work in helping NASA develop longer term solar predictions as a factor in space projects. His work has far more robust peer examinations than most other solar scientists and is way better than armchair amateur soundbites.

Pop Piasa
Reply to  Pamela Gray
August 7, 2017 11:31 am

True story, Pamela. Anyone can gain great insight into all things solar by reading at his site, whether you agree with him or not. I enjoy his frank and unabashed style and his participation here.

August 7, 2017 11:08 am

Mg II index data
The Mg II data are derived from GOME (1995-2011), SCIAMACHY (2002-2012), GOME-2A (2007-present), and GOME-2B (2012-present). All three data sets as well as the Bremen Mg II composite data are available (see links below). In late years the GOME solar irradiance has degraded to about 20% of its value near 280 nm in 1995, so that the GOME data have become noisier. The most recent information on our Mg II data can be found in Snow et al. (2014).
Ozone photochemistry is driven by the interaction of the Sun’s radiation with various gases in the atmosphere, particularly oxygen. The understanding of the basics of ozone photochemistry began with Chapman (1930), who hypothesized that UV radiation was responsible for ozone production and proceeded to lay the foundation of stratospheric photochemistry: the Chapman reactions. He proposed that atomic oxygen is formed by the splitting (dissociation) of O2 by high energy ultraviolet photons (i.e., packets of light energy with wavelengths shorter than 242 nanometers).

August 7, 2017 12:20 pm

What is this all about? Approximately once a week, and the students of Earth to Sky Calculus fly space weather balloons to the stratosphere over California. These balloons are equipped with radiation sensors that detect cosmic rays, a surprisingly “down to Earth” form of space weather. Cosmic rays can seed clouds, trigger lightning, and penetrate commercial airplanes. Furthermore, there are studies ( #1, #2, #3, #4) linking cosmic rays with cardiac arrhythmias and sudden cardiac death in the general population. Our latest measurements show that cosmic rays are intensifying, with an increase of more than 13% since 2015:

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