25 Years of Solar Cycles in One Incredible SOHO Mosaic

For a quarter of a century, the ESA-NASA Solar and Heliospheric Observatory (SOHO) has been essential in helping scientists understand the heart of our Solar System, the Sun. The SOHO mission launched 25 years ago this week, and to celebrate, ESA compiled a wonderful mosaic of images, and NASA put together a remarkable SOHO “greatest hits” timelapse video.

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Do Ripples on the Surface of the Sun tell us that a Flare is Coming?

Flares from the sun are some of the nastiest things in the solar system. When the sun flares, it belches out intense X-ray radiation (and sometimes even worse). Predicting solar flares is a tricky job, and a new research paper sheds light on a possible new technique: looking for telltale ripples in the surface of the sun minutes before the blast comes.

Continue reading “Do Ripples on the Surface of the Sun tell us that a Flare is Coming?”

Solar Orbiter is Already Starting to Observe the Sun

On February 10th, 2020, the ESA’s Solar Orbiter (SolO) launched and began making its way towards our Sun. This mission will spend the next seven years investigating the Sun’s uncharted polar regions to learn more about how the Sun works. This information is expected to reveal things that will help astronomers better predict changes in solar activity and “space weather”.

Last week (on Thursday, Feb. 13th), after a challenging post-launch period, the first solar measurements obtained by the SolO mission reached its international science teams back on Earth. This receipt of this data confirmed that the orbiter’s instrument boom deployed successfully shortly after launch and that its magnetometer (a crucial instrument for this mission) is in fine working order.

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RAISE: How to Capture 1,500 Solar Images in a Five Minute Flight

Quick: how do you aim an instrument at the Sun from a moving rocket on a fifteen minute suborbital flight?

The answer is very carefully, and NASA plans to do just that today, Thursday, November 6th as the Rapid Acquisition Imaging Spectrograph Experiment, also known as RAISE, takes to the skies over White Sands, New Mexico, to briefly study the Sun.

Capturing five images per second, RAISE is expected to gather over 1,500 images during five minutes of data collection near apogee.

Why use sub-orbital sounding rockets to do observations of the Sun? Don’t we already have an armada of space and ground-based instruments to accomplish this that stare at our nearest star around the clock? Well, it turns out that sounding rockets are still cost-effective means of testing and demonstrating new technologies.

“Even on a five-minute flight, there are niche areas of science we can focus on well,” said solar scientist Don Hassler of the Southwest Research Institute in Boulder, Colorado in a recent press release. “There are areas of the Sun that need to be examined with the high-cadence observations that we can provide.”

Indeed, there’s a long history of studying the Sun by use of high-altitude sounding rockets, starting with the detection of solar X-rays by a detector placed in a captured V-2 rocket launched from White Sands in 1949.

Credit: NASA.
Sub-orbital astronomy in 5 minutes: the flight of a sounding rocket. Credit: NASA.

RAISE will actually scrutinize an active region of the Sun turned Earthward during its brief flight to create what’s known as a spectrogram, or an analysis of solar activity at differing wavelengths. This gives scientists a three dimensional layered snapshot of solar activity, as different wavelengths correspond to varying velocities of solar material and wavelengths. Think of looking at layers of cake. This, in turn, paints a picture of how material is circulated and moved around the surface of the Sun.

This will be RAISE’s second flight, and this week’s launch will sport a brand new diffraction grating coated with boron carbide to enhance wavelength analysis. RAISE will also look at the Sun in the extreme ultraviolet which cannot penetrate the Earth’s lower atmosphere. Technology pioneered by missions such as RAISE may also make its way into space permanently on future missions, such as the planned European Space Agency and NASA joint Solar Orbiter Mission, set for launch in 2017. The Solar Orbit Mission will study the Sun close up and personal, journeying only 26 million miles or 43 million kilometres from its surface, well inside the perihelion of the planet Mercury.

“This is the second time we have flown a RAISE payload, and we keep improving it along the way,” Hassler continued. “This is a technology that is maturing relatively quickly.”

As you can imagine, RAISE relies on clear weather for a window to launch. RAISE was scrubbed for launch on November 3rd, and the current window for launch is set for 2:07 PM EST/19:07 Universal Time, which is 12:07 PM MST local time at White Sands. Unlike the suborbital launches from Wallops Island, the White Sands launches aren’t generally carried live, though they tend to shut down US highway 70 between Las Cruces and Alamogordo that bisects White Sands just prior to launch.

Currently, the largest sunspot turned forward towards the Earth is active region 2205.

Another recent mission lofted by a sounding rocket to observe the Sun dubbed Hi-C was highly successful during its short flight in 2013.

RAISE will fly on a Black Brant sounding rocket, which typically reaches an apogee of 180 miles or 300 kilometres.

Credit: NASA/SDO
A look at recent solar activity coming around the solar limb to be targeted by RAISE. Credit: NASA/SDO

Unfortunately, the massive sunspot region AR2192 is currently turned away from the Earth and will effectively be out of RAISE’s view. The largest in over a decade, the Jupiter sized sunspot wowed viewers of the final solar eclipse of 2014 just last month. This large sunspot group will most likely survive its solar farside journey and reappear around the limb of the Sun sometime after November 9th, good news if RAISE is indeed scrubbed today due to weather.

And our current solar cycle has been a very schizophrenic one indeed. After a sputtering start, solar cycle #24 has been anemic at best, with the Sun struggling to come out of a profound minimum, the likes of which hasn’t been seen in over a century. And although October 2014 produced a Jupiter-sized sunspot that was easily seen with eclipse glasses, you wouldn’t know that we’ve passed a solar maximum from looking at the Sun now. In fact, there’s been talk among solar astronomers that solar cycle #25 may be even weaker, or absent all together.

All this makes for fascinating times to study our sometimes strange star. RAISE observations will also be coordinated with views from the Solar Dynamics Observatory and the joint NASA-JAXA Hinode satellites in Earth orbit. We’ll also be at White Sands National Park today, hoping the get a brief view of RAISE as it briefly touches space.

It’s a great time for solar astronomy!

Most Powerful Solar Telescope on Earth Rises Atop Hawaiian Volcano

Rising 10,000 feet above the sunburned faces of 2.2 million tourists a year, the largest solar telescope on the planet is under construction atop Haleakala Crater in Maui, Hawaii. Never mind all those admonitions about never staring at the sun. Astronomers can’t wait for the chance. 

Named for the late Senator Daniel Inouye, the Daniel K. Inouye Solar Telescope or DKIST will be the world’s premier ground-based solar observatory in the world. With its 4-meter (157.5-inch) primary mirror, DKIST is capable of distinguishing features down to 0.03 arc seconds or just 20-70 km (12-44 miles) wide at the sun’s surface. To achieve such fantastic resolutions the telescope will employ the latest adaptive optics technology to cancel the blurring effects of the atmosphere using a computer-controlled deformable mirror. 

capture the evolution of sunspot fine structure and finally understand its physical origin. (Image from the NSO Dunn Solar Telescope, courtesy of Thomas Rimmele.)
Extreme closeup of a sunspot showing the dark, central umbra (top) feathery penumbra and individual granules or hot gas. DKIST will capture the evolution of sunspot fine structure and finally understand its physical origin. Credit: NSO Dunn Solar Telescope, courtesy of Thomas Rimmele

Consider that the smallest features visible in large amateur telescopes are solar granules, columns of hot gas rising up from the sun’s interior. Each spans about 930 miles (1,500 km) and together give the sun’s surface the texture of finely-etched glass. DKIST will resolve features more than 60 times smaller. The current largest sun-dedicated telescope is the McMath-Pierce Solar Telescope , which has kept a steady eye on the home star with its 63-inch (1.6-meter) mirror since 1962 from Kitt Peak, Arizona.

DKIST cutaway showing light entering the top of the dome and gathered by the primary mirror, which is then reflected to a secondary mirror, which reflects the light to a science gallery below. Inset shows the light path in greater detail including the deformable mirror that will cancel the blurring effects of bad atmospheric seeing. Credit: L. Phelps
Observatory cutaway showing light entering the top of the dome and gathered by the primary mirror, which is reflected to a secondary mirror and from there through a series of smaller mirrors to the science gallery below. Inset shows the light path in greater detail including the deformable mirror that will cancel the blurring effects of atmospheric turbulence. Notice that the secondary mirror is offset with no obstructions between it and the primary mirror that would otherwise lessen the telescope’s ability to resolve fine detail. Credit: L. Phelps with enhancements by the author

DKIST will focus on three key areas: What is the nature of solar magnetism; how does that magnetism control our star; and how can we model and predict its changing outputs that affect the Earth? Astronomers hope to clearly resolve  solar flux tubes – magnetic field concentrations near the sun’s surface – thought to be the building blocks of magnetic structures in the atmosphere.

We still lack a complete understanding of how energy in the sun’s turbulent, churning interior is transferred to magnetic fields. Earth’s magnetic field is about 0.5 gauss at the surface. Fields within sunspots can range from 1,500 to 3,000 gauss – about the strength of a bar magnet but across a region several times larger than Earth.

A test of the Visible Broadband Imager (VBI) interference filter that will be used with DKIST
A test of the DKIST Visible Broadband Imager interference filter in 2012 shows material flowing from a sunspot’s outer penumbra into the surrounding solar gases. Credit: NSO

A better understanding of small scale magnetic structures, too tiny to be resolved with current telescopes, will help make sense of broader phenomena like sunspot formation, the heating of the solar corona and why the sun’s energy output varies. The solar constant, the amount of radiation we receive from the sun, increases with an increase in solar activity like spots and flares. Since the smallest magnetic elements are the biggest contributors to this increase, DKIST will be the first telescope able to image and study these structures directly, helping astronomers understand how variations in the sun’s output can lead to climate changes.

Left - Solar photosphere showing bright structures between granules  associated with magnetic fields. RIght - Computer model of a magnetic flux tube rising from the convective  zone into the photosphere. These are believed to be an important  conduit for energy flowing from the solar interior to the hot outer  atmosphere. Flux tubes are below the limit of resolution  in current telescopes. Credit: Paxman, Seldin, Keller / O. Steiner
Left – Solar photosphere showing bright structures between granules associated with magnetic fields bubbling up from below. Right – Computer model of a magnetic flux tube rising from the convective
zone into the photosphere. Flux tubes are believed to be an important
conduit for energy flowing from the solar interior to the hot outer
atmosphere but are below the limit of resolution
in current telescopes. Credit: Paxman, Seldin, Keller / O. Steiner

DKIST will do its work on rapid times scales, taking images once every 3 seconds. For comparison, NASA’s orbiting Solar Dynamics Observatory takes pictures in 8 different wavelengths every 10 seconds, STEREO one image every 3 minutes and SOHO (Solar Heliospheric Observatory) once every 12 minutes. The speedy shooting ability will help DKIST resolve rapidly evolving structures on the sun’s surface and lower atmosphere in a multitude of wavelengths of light from near-ultraviolet to deep infrared thanks to the the extraordinarily clean and dry air afforded by its high altitude digs.

DKIST is under construction in the observatory complex on Haleakala Crater in Maui, Hawaii. The Maui Space Surveillance is the large structure near top center. Photo take Oct. 2013. Credit: Bob King
DKIST is under construction in the observatory complex on Haleakala Crater in Maui, Hawaii. The Maui Space Surveillance Complex is the large structure right of center. Photo take Oct. 2013. Credit: Bob King

The new solar telescope will be in excellent company not far from the current Mees Solar Observatory and a stone’s throw from the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) telescope, the 79-inch (2-meter) Faulkes Telescope North and Maui Space Surveillance Complex which keeps an eye on man-made orbital debris. Tourists to Mt. Haleakala, a popular destination for tourists, can watch it take shape in the next few years while enjoying a hike in the cool air for which Haleakala is famous.

On August 31, 2012 a long filament of solar material that had been hovering in the sun's atmosphere, the corona, erupted out into space at 4:36 p.m. EDT. The coronal mass ejection, or CME, traveled at over 900 miles per second.
On August 31, 2012 a long filament of solar material erupted out into space as a coronal mass ejection, or CME, traveling at over 900 miles per second. By probing solar gases at high resolution and rapid time scales using DKIST’s high power optics and spectrographs, astronomers hope to better understand the first stirrings of these huge outbursts of solar energy. Credit: NASA

I first heard about the DKIST telescope from a burly stranger with fierce-looking tattoos. My wife and I vacationed in Maui last fall. One afternoon, while watching surfers ride the waves near the beach town of Paia, this big guy overheard us mention Duluth (Minn.), our hometown. He said he’d lived in Duluth for a time before moving to Hawaii and offered us a beer. We got to talking and learned he worked safety inspection at at the “biggest solar telescope in the world”, making the hour-long drive up the mountain 5 days a week.  I checked it out and he was absolutely right.

The Daniel K. Inouye Solar Telescope (formerly the Advanced Technology Solar Telescope) is being developed by a consortium led by the National Solar Observatory and comprising the University of Chicago, the New Jersey Institute of Technology, University of Hawaii, the High Altitude Observatory, NASA, the U.S. Air Force and others. For more details on the project, click HERE.

There’s poetry in building a large solar observatory on an island known for its sunny, warm climate. While vacationers flop out on Kaanapali Beach to vanquish the mid-winter chills, astronomers 50 miles away and 10,000 feet up will be at work coaxing secrets from the fiery ball of light that illuminates surf and scope alike.

The Sun Blasts Out Two X-Class Flares, Strongest of the Year

The Sun gets active! On May 12, 2013, the Sun emitted what NASA called a “significant” solar flare, classified as an X1.7, making it the first X-class flare of 2013. Then earlier today, May 13, 2013, the Sun let loose with an even stronger flare, an X2.8-class. Both flares took place just beyond the limb of the Sun, and were also associated with another solar phenomenon, a coronal mass ejection (CME) which sent solar material out into space.

Neither CME was Earth-directed, and according to SpaceWeather.com, no planets were in the line of fire. However, the CMEs appear to be on course to hit NASA’s Epoxi, STEREO-B and Spitzer spacecraft on May 15-16. NASA said their mission operators have been notified, and if warranted, operators can put spacecraft into safe mode to protect the instruments. Experimental NASA research models show that the CMEs were traveling at about 1,930 km/second (1,200 miles per second) when they left the Sun.

The sunspot associated with these flares is just coming into view, and the next 24 to 48 hours should reveal much about the sunspot, including its size, magnetic complexity, and potential for future flares.

See more images and video below:

Both the X1.7 and the X2.8-class solar flare, plus a prominence eruption, all in one video:

SDO image of an X2.8-class flare on May 13, 2013. Credit: NASA/SDO
SDO image of an X2.8-class flare on May 13, 2013. Credit: NASA/SDO

NASA’s Solar Dynamics Observatory (SDO) captured this X1 flare (largest of the year so far) in extreme UV light:

“Bad Boy” Sunspot Unleashes Powerful X-Class Flare

The active region on the Sun that created all the hubbub and aurorae earlier this week put out one last shot before that area of the Sun turns away from Earth’s view. And that shot was a biggie. At 18:37 UT (1:37 pm EST) today (January 27, 2012) sunspot 1402 unleashed an X-class flare, the largest and most powerful category of flares. This flare was measured as an X2, which is at the low end of the highest powered flares, but still, this is the most powerful flare so far this year. It was not directed at Earth, but scientists from the Solar Dynamics Observatory say the energetic protons accelerated by the blast are now surrounding our planet and a S1-class radiation storm is in progress. S1-class is the lowest of 5 (S1 to S5) and has no biological impact, no satellite operations are impacted but some minor impact on HF radio could be experienced.

With all the activity from the Sun, you might need a refresher course in solar flares. Here’s a guide from SDO, and what all the different classifications are:
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Borexino Collaboration Detects pep Neutrinos

View from inside the Borexino neutrino detector. Image Credit: Borexino Collaboration

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Solar neutrino physics has quieted down over the past decade. In the past, it had been a source of major excitement and puzzlement for scientists as they struggled to detect these elusive particles emitted from the fusion reactions in the center of the Sun. Although difficult to detect, they provide the most direct probe of the Solar core. Once astronomers learned to detect them and solved the Solar neutrino problem, they were able to confirm their understanding of the main nuclear reaction that powers the sun, the proton-proton (pp) reaction. But now, astronomers have for the first time, detected the neutrinos of another, far rarer nuclear reaction, the proton-electron-proton (pep) reaction.

At any given time, several separate fusion processes are converting the Sun’s hydrogen into helium, creating energy as a byproduct. The main reaction requires the formation of deuterium (hydrogen with an extra neutron in the nucleus) as the first step in a series of events that leads to the creation of stable helium. This typically takes place by the fusion of two protons which ejects a positron, a neutrino, and a photon. However, nuclear physicists predicted an alternative method of creating the necessary deuterium. In it, a proton and electron fuse first, forming a neutron and a neutrino, and then they join with a second proton. Based on solar models, they predicted that only 0.23% of all Deuterium would be created by this process. Given the already elusive nature of neutrinos, the diminished production rate has made these pep neutrinos even more difficult to detect.

While they may be hard to detect, pep neutrinos are readily distinguishable from ones created by the pp reaction. The key difference is the energy they carry. Neutrinos from the pp reaction have a range of energy up to a maximum of 0.42 MeV, while pep neutrinos carry a very select 1.44 MeV.

However, to pick out these neutrinos, the team had to carefully clean the data of signals from cosmic ray strikes which create muons that could then interact with carbon inside the detector to generate a neutrino with similar energy that might create a false positive. In addition, this process would also create a free neutron. To eliminate these, the team rejected all signals of neutrinos that occurred within a short amount of time from a detection of a free neutron. Overall, this indicated that the detector received 4,300 muons passing through it per day, which would generate 27 neutrons per 100tons of detector liquid, and similarly, 27 false positives.

Removing these detections, the team still found a signal of neutrinos with the appropriate energy and used this to estimate the total amount of pep neutrinos flowing through every square centimeter to be about 1.6 billion, per second, which they note is in agreement with predictions made by the standard model used to describe the interior workings of the Sun.

Aside from further confirming astronomers understanding of the processes that power the Sun, this finding also places constraints on another fusion process, the CNO Cycle. While this process is expected to be minor in the Sun (making only ~2% of all helium produced), it is expected to be more efficient in hotter, more massive stars and dominate in stars with 50% more mass than the Sun. Better understanding the limits of this process would help astronomers to clarify how those stars work as well.

Sun Celebrates Solstice With Flare (and a CME)

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Late in the evening on June 20, 2011 the Sun emitted a long lasting C7.7 class flare (a relatively small flare) that peaked around 11:25p.m. EDT. The flare was associated with a coronal mass ejection that bloomed off the sun at 11:09p.m. EDT (0412 UT).

Spaceweather.com reports that according to analysts at the Goddard Space Flight Center Space Weather Lab, the CME left the sun traveling 800 km/s and it will reach Earth on June 23rd at 23:22 UT (plus or minus 7 hours). A very cool 3D heliospheric model (below) shows the cloud sweeping past our planet. The impact is expected to trigger a G2-class geomagnetic storm.

High-latitude sky watchers should be alert for auroras on June 23rd and 24. The season favors southern hemisphere observers, where skies are darker for longer due to the winter solstice.

These 3D Heliospheric animated models, developed by the Community Coordinated Modeling Center based at the Goddard Space Flight Center, show how the CME cloud might appear as it sweeps past Earth. Credit: NASA/CCMC

Update: SDO posted this video of the event:

Sources: NASA, Spaceweather.com

Monster Prominence Erupts from Sun

Early this morning (June 7, 2011) an amazingly massive and spectacular event took place on the Sun; a huge prominence eruption, marked by a solar flare and release of energetic particles. Daniel Pendick from the Geeked on Goddard blog described it as a “fountain of plasma that blasts out of the solar surface, spreads outward, and collapses to splat back down.”

“I’ve never seen material released like this before, such a huge amount that falls back down in such a spectacular way,” says Dr. C. Alex Young in the video. “It looks like someone just kicked a giant clod of dirt into the air and it fell back down.” Young added that this event will probably not cause any problems as far as space weather affecting Earth.

This video is courtesy NASA Goddard’sHelioviewer.org with narration by folks from The Sun Today.

Below are some still images of the event from the Solar Dynamics Observatory and (just added at 1755 UTC) a video from SDO showing the event in several different wavelengths.

These images were posted by the Camilla_SDO Twitpic feed.

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This is the peak of the M2.5 class solar flare, which propelled the plasma into space today. Credit: NASA/ Solar Dynamics Observatory, via CamillaSDO on Twitter.

The SDO science teams says: “The Sun unleashed an M-2 (medium-sized) solar flare with a substantial coronal mass ejection (CME) on June 7 that is visually spectacular. The large cloud of particles mushroomed up and fell back down looking as if it covered an area of almost half the solar surface.”

“SDO observed the flare’s peak at 1:41 AM EST. SDO recorded these images in extreme ultraviolet light and they show a very large explosion of cool gas. It is somewhat unique because at many places in the eruption there seems to be even cooler material — at temperatures less than 80,000K.”

Update: The US National Weather Service Space Weather Prediction center has now warned that the solar flare, one of the largest to occur since December 2006, will likely lead to gemagnetic storm activity tomorrow, Wednesday.

The NWS stated: “A dramatic eruption from an otherwise unimpressive NOAA Region 1226 earlier today is expected to cause G1 (minor) to G2 (moderate) levels of geomagnetic storm activity tomorrow, June 8, beginning around 1800 UTC with the passage of a fast CME. A prompt Solar Radiation Storm reached the S1 (minor) level soon after the impulsive R1 (minor) Radio Blackout at 0641 UTC. The Solar Radiation Storm includes a significant contribution of high energy (>100 MeV) protons, the first such occurrence of an event of that type since December 2006.”

You can find updates from the Space Weather Prediction Center at this link.