Solar Dynamics Observatory Archives

July 15, 2016September 20, 2016 by Evan Gough

A Dark Region Is Growing Eerily On The Sun’s Surface

NASA's Solar Dynamics Observatory has captured images of a growing dark region on the surface of the Sun. Called a coronal hole, it produces high-speed solar winds that can disrupt satellite communications. Image: Solar Dynamics Observatory / NASA

NASA has spotted an enormous black blotch growing on the surface of the Sun. It looks eerie, but this dark region is nothing to fear, though it does signal potential disruption to satellite communications.

The dark region is called a coronal hole, an area on the surface of the Sun that is cooler and less dense than the surrounding areas. The magnetic fields in these holes are open to space, which allows high density plasma to flow out into space. The lack of plasma in these holes is what makes them appear dark. Coronal holes are the origin of high-speed solar winds, which can cause problems for satellite communications.

The images were captured by the Solar Dynamics Observatory (SDO) on July 11th. Tom Yulsman at Discover’s ImaGeo blog created a gif from several of NASA’s images.

High-speed solar winds are made up of solar particles which are travelling up to three times faster than the solar wind normally does. Though satellites are protected from the solar wind, extremes like this can still cause problems.

Coronal holes may look like a doomsday warning; an enormous black hole on the surface of our otherwise placid looking Sun is strange looking. But these holes are a part of the natural life of the Sun. And anyway, they only appear in extreme ultraviolet and x-ray wavelengths.

The holes tend to appear at the poles, due to the structure of the Sun’s magnetosphere. But when they appear in more equatorial regions of the Sun, they can cause intermittent problems, as the high-speed solar wind they generate is pointed at the Earth as the Sun rotates.

In June 2012, a coronal hole appeared that looked Big Bird from Sesame Street.

The "Big Bird" coronal hole appeared on the Sun in June 2012. It caused a powerful storm that was considered a near miss for Earth. Image: NASA/AIA — The “Big Bird” coronal hole appeared on the Sun in June 2012. It was the precursor to a powerful storm that was considered a near miss for Earth. Image: NASA/AIA

The Big Bird hole was the precursor to an extremely powerful solar storm, the most powerful one in 150 years. Daniel Baker, of the University of Colorado’s Laboratory of Atmospheric and Space Physics, said of that storm, “If it had hit, we would still be picking up the pieces.” We were fortunate that it missed us, as these enormous storms have the potential to damage power grids on the surface of the Earth.

It seems unlikely that any solar wind that reaches Earth as a result of this current coronal hole will cause any disruption to us here on Earth. But it’s not out of the question. In 1989 a solar storm struck Earth and knocked out power in the province of Quebec in Canada.

It may be that the only result of this coronal hole, and any geomagnetic storms it creates, are more vivid auroras.

Those are something everyone can appreciate and marvel at. And you don’t need an x-ray satellite to see them.

August 25, 2014December 23, 2015 by Elizabeth Howell

Kapow! Moderate Solar Flare Erupts From The Sun, But Likely Won’t Affect Earth

Hot material shines brightly in this close-up of a moderate flare erupting on the sun Aug. 24, 2014. Credit: NASA/SDO

While this solar peak has been weaker than usual, from time to time we get a moderate punch from the Sun. Here’s an example — what NASA calls a “mid-level” solar flare blasting off the Sun at 8:16 a.m. EDT (1:16 p.m. UTC) yesterday (Aug. 26).

While the related coronal mass ejection can cause auroras high in Earth’s atmosphere and (in more severe cases) cause telecommunications disruptions, in this case the U.S. government isn’t expecting much.

“Given the location of this event, the associated coronal mass ejection is well off the Sun-Earth line and no significant geomagnetic storming is anticipated as a result,” wrote the National Weather Service’s Space Weather Prediction Center in an update today.

NASA says the flare, which was captured by the Solar Dynamics Observatory, is an M5 flare. X-class flares are about 10 times more powerful than M-class ones.

An unrelated solar event recently caused auroras that astronauts spotted from the International Space Station.

March 31, 2014December 23, 2015 by Elizabeth Howell

Aurora Alert: Powerful Solar Flare This Weekend Could Spark Show Tomorrow

Extreme ultraviolet light streams out of an X-class solar flare as seen in this image captured on March 29, 2014, by NASA's Solar Dynamics Observatory. This image blends two wavelengths of light: 304 and 171 Angstroms, which help scientists observe the lower levels of the sun's atmosphere. Image Credit: NASA/SDO.

If you sit at a fairly high latitude, you may want to keep an eye out your window Tuesday (April 1) and Wednesday. A powerful X-1 class flare erupted from the sun on Saturday (March 29), sparking an active space weather forecast from the National Oceanic and Atmospheric Administration.

The solar flare erupted from sunspot AR2017 and happened to be aimed at the right direction to bring material to Earth. The associated coronal mass ejections (CMEs) will send streams of particles towards our planet, which could get pulled towards the poles and cause light shows as they interact with molecules in the upper atmosphere.

“NOAA forecasters estimate a 35 percent to 60 percent chance of polar geomagnetic storms on April 1-2 when at least three CMEs are expected to deliver glancing blows to Earth’s magnetic field,” SpaceWeather.com wrote. “The best-guess forecast calls for minor G1-class storms. High-latitude sky watchers should be alert for auroras.”

Aurora seen near Fairbanks, Alaska on March 21, 2014. Credit and copyright: John Chumack.

At the top of this story, you can view a video of the flare from the Solar Dynamics Observatory, a NASA satellite launched in 2010 to observe the sun’s activity. This not only has applications for aurora watchers, but also for those people concerned about the effect CMEs have on Earth’s satellites, power lines and other sensitive infrastructure.

Below is an older picture from the Solar and Heliospheric Observatory, a joint NASA and European Space Agency mission that also keeps an eye on solar activity. The sun has an 11-year cycle of solar activity, and you can see peak year 2001 at the front of the image along with quieter years 1996 and 2006 near the back. The year 2014 is just off the peak for this solar cycle.

If you catch a light show, be sure to post it on the Universe Today Flickr pool, and we may include it in a future story!

A solar cycle in X-rays. The peak in 2001 is visible at the front, with quietest years 1996 and 2006 near the back. The sun's 11-year-solar cycle sees an increase in sunspots and solar activity at its peak. The year 2014 is close to the peak year for activity, but the cycle has been more muted than the 2001 cycle. Credit: Steele Hill, SOHO, NASA/ESA — A solar cycle in X-rays. The peak in 2001 is visible at the front, with quietest years 1996 and 2006 near the back. The sun’s 11-year-solar cycle sees an increase in sunspots and solar activity at its peak. The year 2014 is close to the peak year for activity, but the cycle has been more muted than the 2001 cycle. Credit: Steele Hill, SOHO, NASA/ESA

March 28, 2014December 23, 2015 by Elizabeth Howell

Slip-Sliding Away: Solar Flare’s Magnetic Lines Go For A Loop In This Video

Our own Sun produces flares, but we are protected by our magnetosphere, and by the distance from the Sun to Earth. Credit: NASA/ Solar Dynamics Observatory,

When will the next big solar flare occur? How much damage could it cause to power lines and satellites? These are important questions for those looking to protect our infrastructure, but there’s still a lot we need to figure out concerning space weather.

The video above, however, shows magnetic lines weaving together from the surface of the Sun in 2012, eventually creating an eruption that was 35 times our planet’s size and sending out a surge of energy. It’s these energetic flares that can hit Earth’s atmosphere and cause auroras and power surges.

While models of this have been made before, this is the first time the phenomenon was caught in action. Scientists saw it using NASA’s Solar Dynamics Observatory.

Models of the flares show they typically occur amid distorted magnetic fields, the University of Cambridge noted, showing that the lines can “reconnect while slipping and flipping around each other.” Before the flare happens, the magnetic field lines line up in an arc across the sun’s surface (photosphere). That phenonemon is called field line footprints.

“In a smooth, non-entangled arc the magnetic energy levels are low, but entanglement will occur naturally as the footpoints move about each other,” the release added. “Their movement is caused as they are jostled from below by powerful convection currents rising and falling beneath the photosphere. As the movement continues, the entanglement of field lines causes magnetic energy to build up.”

When the energy gets to great, the lines let go of the energy, creating the solar flare and coronal mass ejection that can send material streaming away from the sun. A note, this observation was made of an X-class flare — the strongest kind of flare — and scientists say they are not sure if this phenomenon is true of all kinds of flares. That said, the phenomenon would be harder to spot in smaller flares.

You can read more about the research in the Astrophysical Journal or in preprint version on Arxiv. It was led by Jaroslav Dudik, a researcher at the University of Cambridge’s center for mathemetical sciences.

Source: University of Cambridge

February 25, 2014December 23, 2015 by Elizabeth Howell

Yesterday’s Mammoth Solar Flare Is The Biggest Of 2014 So Far

NASA's Solar Dynamics Observatory captured these images of a large flare erupting from the sun Feb. 21, 2014. Credit: NASA/SDO

She’s a rainbow! You can see the first moments of a huge flare belching off the sun in the picture above. The so-called X-class flare erupted a few hours ago (at 7:25 p.m. EST Feb. 24, or 12:25 a.m. UTC Feb. 25) and was captured by several spacecraft. If you have a pictures of the sun yourself to share, feel free to post them in the Universe Today Flickr pool.

NASA’s Solar Dynamics Observatory saw the flare growing in at least six different wavelengths of light, which are visible in the image above. This is classified this as an X4.9-class flare, which shows that it is pretty strong. X-flares are the most powerful kind that the sun emits, and each X number is supposed to be twice as intense as the previous one (so an X-2 flare is twice as powerful as X-1, for example).

SpaceWeather.com says this is the most powerful flare of the year so far, emitted from sunspot AR1967 (or more properly speaking, AR1990; sunspots are renamed if they survive a full rotation of the sun, as this one has done twice already!) While solar flares can lead to auroras, in this case it appears the blast was pointed in the wrong direction, the site added.

“Although this flare is impressive, its effects are mitigated by the location of the blast site–near the sun’s southeastern limb, and not facing Earth,” SpaceWeather stated. “Indeed, a bright coronal mass ejection (CME) which raced away from the sun shortly after the flare appears set to miss our planet.”

This image from the Solar and Heliospheric Observatory illustrates increased solar activity between Feb. 18-20, 2014. Credit: ESA/NASA/SOHO/GSFC

The sun goes through an 11-year cycle of sunspot and solar activity, which is supposed to be at its peak right now. This particular peak has been very muted, but lately things have been picking up. The European Space Agency noted that between Feb. 18 and 20, the sun sent out six CMEs in three days, with most of them moving in different directions.

“This level of activity is consistent with what we might expect as the Sun is near its maximum period of activity in the 11-year solar cycle,” ESA stated.

You can see the sun changing on this SDO page, showing the latest views of the sun in different wavelengths. And for more information on sunspots, check out this NASA page explaining a little more about how they work.

January 30, 2014December 23, 2015 by Bob King

A Secret Solar Eclipse from Outer Space

The sun seen in six different colors of wavelengths of light as the moon passed across from the perspective of NASA's Solar Dynamics Observatory this morning between about 7:30 and 10 a.m. CST. Credit: NASA

Call it the eclipse nobody saw. NASA’s Solar Dynamics Observatory (SDO) got its own private solar eclipse showing from its geosynchronous orbital perch today. Twice a year during new phase, the moon glides in front of the sun from the observatory’s perspective. Although we can’t be there in person to see it, the remote view isn’t too shabby. The events are called lunar transits rather than eclipses since they’re seen from outer space. Transits typically last about a half hour, but at 2.5 hours, today’s was one of the longest ever recorded. The next one occurs on July 26, 2014.

Today’s lunar transit of the sun followed by a strong solar flare

When an eclipse ends, the fun is usually over, but not this time. Just as the moon slid off the sun’s fiery disk, a strong M6.6 solar flare exploded from within a new, very active sunspot group rounding the eastern limb and blasted a CME (coronal mass ejection) into space. What a show!

Approximate view of the moon transiting the sun from SDO's viewpoint. Credit: NASA — Approximate view of the moon transiting the sun from SDO’s viewpoint. To make sure SDO didn’t run down its batteries when the sun was blocked, mission control juiced them up beforehand. Credit: NASA

SDO circles Earth in a geosynchronous orbit about 22,000 miles high and photographs the sun continuously day and night from a vantage point high above Mexico and the Pacific Ocean. About 1.5 terabytes of solar data or the equivalent of half a million songs from iTunes are downloaded to antennas in White Sands, New Mexico every day.

For comparison, the space station, which orbits much closer to Earth, would make a poor solar observatory, since Earth blocks the sun for half of every 90 minute orbit.

When you look at the still pictures and video, notice how distinct the edge of the moon appears. With virtually no atmosphere, the moon takes a “sharp” bite out of the sun.

SDO orbits about 22,000 miles above Earth, tracing out a figure-8 (called an analemma) above the Pacific and Mexico every 24 hours. Credit: NASA Read more: http://www.universetoday.com/#ixzz2ruidvZJ5 — SDO orbits about 22,000 miles above Earth, tracing out a figure-8 (called an analemma) above the Pacific and Mexico every 24 hours. Credit: NASA
Read more: http://www.universetoday.com/#ixzz2ruidvZJ5

SDO amazes with its spectacular pictures of the sun taken in 10 different wavelengths of light every 10 seconds; additional instruments study vibrations on the sun’s surface, magnetic fields and how much UV radiation the sun pours into space.

Compared to all the hard science, the twice a year transits are a sweet side benefit much like the cherries topping a sundae.

You can make your own movie of today’s partial eclipse by visiting the SDO website and following these easy steps:

* Click on the Data tab and select AIA/HMI Browse Data
* Click on the Enter Start Date window, select a start date and time and click Done
* Click on Enter End Date and click Done
* Under Telescopes, pick the color (wavelength) sun you want
* Select View in the display box
* Click Submit at the bottom and watch a video of your selected pictures

November 29, 2013December 23, 2015 by Elizabeth Howell

Zombie ISON ‘Behaving Like A Comet’, Stunned Astronomers Say

Bright, brighter, brightest: these views of Comet ISON after its closest approach to the sun Nov. 28 show that a small part of the nucleus may have survived the comet's close encounter with the sun. Images from the Solar and Heliospheric Observatory. Credit: ESA/NASA/SOHO/GSFC

Talk about the Comeback Kid. After Comet C/2012 S1 ISON rounded the sun yesterday afternoon, professional astronomers around the world looked at the faded debris and concluded it was an “ex-comet.” NASA wrapped up an hours-long Google+ Hangout with that news. The European Space Agency declared it was dead on Twitter.

But the remnants — or whatever ISON is now — kept brightening and brightening and brightening in images from the NASA/European Space Agency Solar and Heliospheric Observatory. The pictures are still puzzling astronomers right now, almost a day after ISON’s closest encounter with the sun.

You can follow our liveblogged confusion yesterday, capped by a gobsmacking announcement from the Naval Research Laboratory’s Karl Battams, “We believe some small part of ISON’s nucleus has SURVIVED perihelion,” he said on Twitter. Since then, Battams wrote a detailed blog post, referring to images from the Large Angle and Spectrometric Coronagraph (LASCO) aboard SOHO:

“Matthew [Knight] and I are ripping our hair out right now as we know that so many people in the public, the media and in science teams want to know what’s happened. We’d love to know that too! Right now, here’s our working hypothesis: As comet ISON plunged towards to the Sun, it began to fall apart, losing not giant fragments but at least a lot of reasonably sized chunks. There’s evidence of very large dust in the form of that long thin tail we saw in the LASCO C2 images.

After its closest approach to to the sun on Nov. 28 (left), Comet ISON appeared a dim shadow of its former self (at right). "The comet may still be intact," NASA wrote on Nov. 29. Images from the Solar and Heliospheric Observatory. Credit: ESA/NASA/SOHO/Jhelioviewer — After its closest approach to to the sun on Nov. 28 (left), Comet ISON appeared a dim shadow of its former self (at right). “The comet may still be intact,” NASA wrote on Nov. 29. Images from the Solar and Heliospheric Observatory. Credit: ESA/NASA/SOHO/Jhelioviewer

Then, as ISON plunged through the corona, it continued to fall apart and vaporize, and lost its coma and tail completely just like Lovejoy did in 2011. (We have our theories as to why it didn’t show up in the SDO images but that’s not our story to tell – the SDO team will do that.) Then, what emerged from the Sun was a small but perhaps somewhat coherent nucleus, that has resumed emitting dust and gas for at least the time being. In essence, the tail is growing back, as Lovejoy’s did.

So while our theory certainly has holes, right now it does appear that a least some small fraction of ISON has remained in one piece and is actively releasing material. We have no idea how big this nucleus is, if there is indeed one. If there is a nucleus, it is still too soon to tell how long it will survive. If it does survive for more than a few days, it is too soon to tell if the comet will be visible in the night sky. If it is visible in the night sky, it is too soon to say how bright it will be…

This morning (EST), Battams succinctly summarized the latest images he saw: “Based on a few more hours of data, comet #ISON appears to be… well, behaving like a comet!”, he wrote on Twitter.

NASA issued a status update this morning saying it’s unclear if this leftover is debris or an actual nucleus, but added that “late-night analysis from scientists with NASA’s Comet ISON Observing Campaign suggest that there is at least a small nucleus intact.” NASA, as well as Battams, pointed out that comet has behaved unpredictably throughout the 15 months scientists and amateurs have been observing it.

Mike Hankey of Monkton, Maryland took this photo of Comet ISON in outburst this morning Nov. 14. The tail now shows multiple streamers. Click to enlarge. Credit: Mike Hankey — Mike Hankey of Monkton, Maryland took this photo of Comet ISON in outburst Nov. 14. The tail showed multiple streamers. Click to enlarge. Credit: Mike Hankey

Throughout the year that researchers have watched Comet ISON – and especially during its final approach to the sun – the comet brightened and dimmed in unexpected ways. Such brightness changes usually occur in response to material boiling off the comet, and different material will do so at different temperatures thus providing clues as to what the comet is made of. Analyzing this pattern will help scientists understand the composition of ISON, which contains material assembled during the very formation of the solar system some 4.5 billion years ago.

Slate Bad Astronomy blogger Phil Plait jokingly threw out phrases like “What the what?” on Twitter yesterday, but added in a late-night update: “If you haven’t figured this out yet: We are *loving* this. The Universe surprises us yet again! How awesome!” He continued with his astonishment in a blog post:

For those keeping score at home, it got bright, then it faded, then it got all smeared out, then it came around the Sun smeared out, and then it seemed to get its act together again. At this point, I refuse to make any further conclusions about this comet; it seems eager to confuse. I’ve been hearing from comet specialists who are just as baffled… which is fantastic! If we knew what was going on, there’d be nothing more to learn.

Science confusion: Comet ISON made its closest approach to the sun Nov. 28. Although it showed up again in images from the Solar and Heliospheric Observatory, scientists could not spot it using the ESA PROBA-2 spacecraft (view pictured). ISON's composition or proximity to the sun may have caused this. Credit: PROBA-2 Science Centre — Science confusion: Comet ISON made its closest approach to the sun Nov. 28. Although it showed up again in images from the Solar and Heliospheric Observatory, scientists could not spot it using the ESA PROBA-2 spacecraft (view pictured). ISON’s composition or proximity to the sun may have caused this. Credit: PROBA-2 Science Centre

In a series of Twitter posts this morning, the European Space Agency’s science feed offered this take from Gerhard Schwehm, ESA’s head of planetary science:

From my initial look at ISON in today’s SOHO images, it seems nucleus has mostly disintegrated. Will only know if part of ISON nucleus has survived by continuing observations and performing more analysis. Bright fan-shape implies lots of material was released and travelling along ISON orbit, not confined in a traditional tail. Would be interesting to learn more about composition of debris to help us piece together what’s happened, but we need more time.

Other spacecraft searching for ISON were not able to spot it. For ESA’s PROBA-2, it may have been because of its composition or proximity to the sun, but scientists are unsure. It was also invisible in NASA’s Solar Dynamics Observatory; “scientists are still looking at the data to figure out why,” an agency Twitter update stated this morning.

So to sum up: no one’s quite sure of what is happening now, or what is happening next, but we will keep you posted and let you know if and when you can see ISON again in your home telescopes.

One of the finest pictures to date of Comet ISON by ace astrophotographer Damian Peach taken on Oct. 27.

November 28, 2013December 23, 2015 by Elizabeth Howell

Is Comet ISON Dead? Astronomers Say It’s Likely After Icarus Sun-Grazing Stunt

Comet ISON on Nov. 10 before the recent outburst with well-developed dust (upper) and gas tails. Click ot enlarge. Credit: Damian Peach

Update, 9:55 pm EST: It’s a Thanksgiving miracle: apparently it now looks like ISON has actually survived!!

Alright we're calling it, and you heard it here first: We believe some small part of #ISON's nucleus has SURVIVED perihelion.

— Sungrazer Comets (@SungrazerComets) November 29, 2013

Image from SOHO indicates a chunk of Comet ISON has survived its close pass of the Sun. Credit: NASA/ESA/SOHO.

Update, 8:35 p.m. EST: Uncertainty about Comet ISON’s fate likely will persist for some time. Karl Battams just tweeted that after 2,000 sungrazing comet observations, he has never seen brightening in the same way that ISON (or its remains) appear to be doing right now. We’ll keep watching. Real-time images are available on this website.

Update, 6:30 p.m. EST: An excellent blog post from Phil Plait (who writes the Bad Astronomy blog on Slate) summarizes his take of the comet’s fate; debris (most likely, he says) continues to show up in images. An except: “It held together a long time, got very bright last night, faded this morning, then apparently fell apart. This isn’t surprising; we see comets disintegrate often enough as they round the Sun. ISON’s nucleus was only a couple of kilometers across at best, so it would have suffered under the Sun’s heat more than a bigger comet would have. Still, there’s more observing to do, and of course much data over which to pore.”

Update, 4:40 p.m. EST: On Twitter, the European Space Agency (quoting SOHO scientist Bernhard Fleck) said the comet is gone. Separately, the Naval Research Laboratory’s Karl Battams posted that he thinks recent observations show debris from ISON, but not a nucleus. Astronomers are still monitoring, however.

Update, 3:56 p.m. EST: Something has emerged from perihelion, but the experts are divided as to whether it’s leftovers of ISON’s tail, or the comet itself. Stay tuned.

The fate of Comet C/2012 S1 ISON is uncertain. It made its closest approach to the sun today (Nov. 28) around 1:44 p.m. EST (6:44 p.m. UTC). As of Thursday night, what’s happening to the comet is still unclear, as observers try to keep up hopes for a good comet show in the next few weeks.

It will take a few more hours until NASA and other agencies can say for sure what the comet’s fate is. That said, there still is valuable science that can be performed if ISON has broken up — more details below the jump.

ISON coincided with American Thanksgiving, causing a lot of astronomers and journalists to work holiday hours while pundits made jokes about the comet being “roasted” along with the turkey. Meanwhile, amateur astronomer Stuart Atkinson — author of the Waiting for ISON blog — was among those eagerly awaiting the comet’s closest approach.

But as the comet made its closest approach, astronomers grew more and more skeptical than it had survived. Phil Plait (who writes the Bad Astronomy blog on Slate) pointed out that the comet’s nucleus appeared much dimmer than its tail in images from SOHO (Solar and Heliospheric Observatory), NASA’s sun-gazing spacecraft. This implied that the nucleus was disintegrating.

Plait and Karl Battams — a Naval Research Laboratory astrophysicist who operates the Sungrazing Comets Project — both participated in a NASA Google+ Hangout on ISON. As of about 2 p.m. EST (7 p.m. UTC), both said that they believe ISON is an “ex-comet”, although it will be a few more hours before scientists can say for sure.

The challenge is that the two spacecraft used to watch ISON swing around the sun — the Solar Dynamics Observatory and SOHO — are not necessarily designed to look for comets. Battams and Plait initially said that it sometimes take additional image processing to view information in it. more As time elapsed though, both expressed extreme skepticism that the comet survived.

Even if the comet is dead, Plait pointed out that scientists can still learn a lot from the remaining debris. ISON is believed to be a pristine example of bodies in the Oort Cloud, a vast body of small objects beyond the orbit of Neptune. Examining the dust in its debris trail could tell scientists more about the origins of the solar system.

“The fact that it’s broken up is really cool. There’s a lot we can learn from it and a lot we can get from it,” he said.

Battams added that ISON has been a very unpredictable comet, flaring up when people expected it would fade, and vice versa. “ISON is just weird. It has behaved unpredictably at times. When it’s done something strange, we spent some time scratching our heads, figuring out what is going on and we think we know what it’s doing … it then goes and does something different.”

Amid the waiting came the inevitable social media jokes (including science fiction and fantasy references.)

For others, the comet served as an inspiration for daring to be courageous.

June 24, 2013December 23, 2015 by Elizabeth Howell

This Energy-Boosting Region In The Sun Will Have A New NASA Satellite Watching It

IRIS will take a closer look at the lower parts of the sun's atmosphere, which is producing the spectacular flare shown in this image. Credit: NASA&JAXA/Hinode

How does the sun’s energy flow? Despite the fact that we live relatively close (93 million miles, or eight light-minutes) to this star, and that we have several spacecraft peering at it, we still know little about how energy transfers through the solar atmosphere.

NASA’s next solar mission will launch Wednesday, June 26 (if all goes to plan) to try to learn a little bit more. It’s called the Interface Region Imaging Spectrograph (IRIS), and it will zero in on a spot in the sun’s lower atmosphere known as the “interface region.” The zone only has a thickness of 3,000 to 6,000 miles and is seen as a key transfer point to the sun’s incredibly hot corona (that you can see during total solar eclipses.)

“IRIS will extend our observations of the sun to a region that has historically been difficult to study,” stated Joe Davila, IRIS project scientist at NASA’s Goddard Space Flight Center. “Understanding the interface region better improves our understanding of the whole corona and, in turn, how it affects the solar system.”

Figuring out more about the interface region, NASA stated, will teach us a lot more about the “space weather” that affects Earth.

Some of the energy in the interface region leaks out and powers the solar wind, which is a sort of rain of particles that leave the star. Some of them hit the Earth’s magnetic field and can produce auroras. Most of the sun’s ultraviolet radiation also flows from the interface region.

IRIS’ images will be able to zero in on about 1 percent of the sun in a single go, with resolution of features of as small as 150 miles. The 400-pound satellite will orbit Earth in an orbit perpetually keeping it above the sunrise line, a spot that lets the satellite look at the sun continuously for eight months without the sun being obscured by Earth.

It’ll also form part of a larger network of sun-staring satellites.

Technicians work on NASA’s Interface Region Imaging Spectrograph (IRIS) in a "clean room", a specially designed facility intended to minimize contaminants on spacecraft before launch. Credit: Lockheed Martin — Technicians work on NASA’s Interface Region Imaging Spectrograph (IRIS) in a “clean room”, a specially designed facility intended to minimize contaminants on spacecraft before launch. Credit: Lockheed Martin

NASA highlighted its Solar Dynamics Observatory and a joint mission it has with Japan, called Hinode, which both take images of the sun in high-definition. These other two observatories, however, look at different solar layers (specifically, the surface and the outer atmosphere).

With IRIS joining the fleet and looking at the interface region, it will provide a more complete picture.

“Relating observations from IRIS to other solar observatories will open the door for crucial research into basic, unanswered questions about the corona,” stated Davila.

Source: NASA

February 20, 2013December 23, 2015 by Nancy Atkinson

New Video Shows Fire and ‘Rain’ on the Sun

Screenshot of a dazzling magnetic display on the Sun, a phenomenon known as coronal rain. Credit: NASA/SDO

This footage was obtained by the AIA instrument on the Solar Dynamics Observatory on July 19, 2012. It provides a stunning display of solar activity and shows how wildly different events on the Sun can be. Some come just with a solar flare, some with an additional ejection of solar material called a coronal mass ejection (CME), and some with complex moving structures in association with changes in magnetic field lines that loop up into the Sun’s atmosphere, the corona.

This eruption produced all three.

A moderately powerful solar flare exploded on the Sun’s lower right hand limb, sending out light and radiation. Next came a CME, which shot off to the right out into space. And then, the Sun treated viewers to one of its dazzling magnetic displays — a phenomenon known as coronal rain.

Over the course of the next day, hot plasma in the corona cooled and condensed along strong magnetic fields in the region. Magnetic fields, themselves, are invisible, but the charged plasma is forced to move along the lines, showing up brightly in the extreme ultraviolet wavelength of 304 Angstroms, which highlights material at a temperature of about 50,000 Kelvin. This plasma acts as a tracer, helping scientists watch the dance of magnetic fields on the Sun, outlining the fields as it slowly falls back to the solar surface.

SDO collected one frame every 12 seconds, and the movie plays at 30 frames per second, so each second in this video corresponds to 6 minutes of real time. The video covers 12:30 a.m. EDT to 10:00 p.m. EDT on July 19, 2012.