Here’s more video from the huge explosion on the Sun on June 7, 2011, which began at about 06:41 UTC. Not only was this event one of the most spectacular ever recorded, but also one of the best observed, with complementary data from several spacecraft and different vantage points. This video shows data from three different space observatories. The Solar Dynamics Observatory’s Atmospheric Imaging Assembly recorded the amazing event in stunning detail in different wavelengths. Additionally, the Solar & Heliospheric Observatory’s (SOHO) LASCO coronagraph and STEREO’s (Solar Terrestrial Relations Observatory) SECCHI instrument suite observed the prominence and associated CME as they traveled out into the heliosphere. Using LASCO and SECCHI data, the speed of the leading edge of the CME was estimated to be in the range 1200 – 1600 km/s. Model calculations predict that Earth will receive a glancing blow of the CME on June 10, possibly sparking some nice aurorae at high latitudes, according to the SDO team.
The citizen science project Solar Storm Watch predicts a solar storm to reach Earth at 08:00 UTC on June 10, 2011 with a glancing blow 35 degrees behind Earth, with a second storm expected at 19:00 UTC on June 10, 2011, with another glancing blow 32 degrees behind Earth.
The event originated from the almost spotless active region 11226 and was associated with a moderate M2-class X-ray flare. The CME and associated shock wave produced and S1-class radiation storm, which shows up as speckles in the LASCO movies.
The size of the prominence is thought to be at least 75 times the size of Earth. Our Jason Major created a graphic showing the size comparison. Earth is the little teeny tiny blue circle in the top left corner:
The primary mission of the twin STEREO probes is to explore the 3-dimensional makeup of our Sun. Each craft carries a variety of instruments. One of them, the Heliospheric Imager (HI), doesn’t look directly at the Sun, but rather, explores a wide field near the Sun in order to explore the physics of coronal mass ejections (CMEs), in particular, ones aimed at the Earth. But while not focusing on solar ejections, the HI is free to make many other observations, including its first detection of an extrasolar planet.
As the Heliospheric Imager stares at the space between the Earth and Sun, it has made many novel observations. The device first opened its shutters in 2006 the instrument has observed the interaction of CMEs with the atmosphere of Venus, the stripping of a tail of a comet by a CME, atomic iron in a comet’s tail, and “the very faint optical emission associated with so-called Corotating Interaction Regions (CIRs) in interplanetary space, where fast-flowing Solar wind catches up with slower wind regions.”
The spacecraft allows for long periods of time to stare at patches of sky as the satellites precede and follow Earth in its orbit. The spacecraft is able to take pictures roughly every 40 minutes for almost 20 days in a row giving excellent coverage. As a result, the images taken have the potential to be used for detailed survey studies. Such information is useful for conducting variable star studies and a recent summary of findings from the mission reported the detection of 263 eclipsing variable stars, 122 of which were not previously classified as such.
Another type of variable star observed by the STEREO HI, was the cataclysmic sort, in particular, V 471 Tau. This red giant/white dwarf binary in the Hyades star cluster is a strong source of interest for stellar astrophysicists because the system is suspected to be a strong candidate for a type Ia supernova as the red giant dumps mass onto its high mass, white dwarf companion. The star system is extremely erratic in its light output and observations could help astronomers understand how such systems evolve.
Although planetary hunting is at the very edge of the capabilities of the HI’s limitations, eclipses caused by planet sized objects are feasible for many of the brighter stars in the field of view as dim as approximately 8th magnitude. Around one star, HD 213597, the STEREO team reported the detection of an object that seems too small to be a star based on the light curve alone. However, follow up studies will be necessary to pin down the object’s mass more accurately.
Super Bowl SUNday XLV marks a watershed moment in observing our Sun. Today, February 6, 2011, NASA’s twin STEREO solar observatories will reach locations on exact opposite sides of the Sun, called opposition, and they are beaming back uninterrupted images from both the entire front and rear side hemispheres of Earths star in three dimensions and 360 degrees for the first time.
“For the first time in history we can see the entire Sun at one time – both the far side and the near side,” said Joe Gurman, in an interview for Universe Today. Gurman is the Project Scientist for NASA’s STEREO mission at the NASA Goddard Spaceflight Center in Greenbelt, MD. This will significant aid space weather forecasting.
To mark this historic milestone, NASA today released images captured by STEREO on Feb. 2 – slightly prior to opposition – which gives humankind our first ever global look at the whole sphere of our Suns surface and atmosphere in extreme ultraviolet light (EUV). The probes were over 179 degrees apart. See location maps and images below
This article features even newer EUV images – compared to NASA’s press release – that were taken even closer to opposition by STEREO on Feb. 3 and today on Feb. 6 and which I downloaded from the STEREO website. The newer EUV images show an ever so slightly more complete solar view as the probes orbit reaches further to the suns far side.
Coincidentally, the STEREO duo may reach opposition – exactly 180 degrees apart – while the Super Bowl XLV half time show is ongoing, at roughly 7:30 p.m. EST in the evening of Sunday, Feb. 6.
There is a tiny sliver of unseen solar surface on the far side of the sun at the extreme fringes of the far side EUV images that will fill in over the new few days to give an even better view. As of today that wedge is less than 1 degree. See the solar image collections above and below.
“The currently unseen far side wedge will disappear around February 12,” Gurman told me. “There might still be some small areas at high latitudes we won’t be able to see, but the view from the ecliptic is always limited. It takes about 3 days to get back the high resolution data.”
“On either side of the wedge, the features are smeared out because they’re from the “limbs” (edges) of the Sun as seen from each STEREO spacecraft.”
“The far side resolution will increase as the STEREO twins proceed around the sun.”
“On the near side, we can substitute the much higher resolution SDO AIA image data along the nearside “seam”, said Gurman.
SDO is in Earth orbit on the earth-facing side of the sun and will fill in the gap.
“For the next 8 years we will have a 360 degree view of the Sun by combining STEREO and SDO data,” said Gurman. “We will have that whole sun view until the STEREO spacecraft swing back to the earth side of the Sun.”
Why is it important to image the far side of the sun?
Because scientists can now immediately detect active regions on the far side of the sun which were hidden from our view up until now.
“No active region can hide from us anymore because we will now have this 360 degree view.”
The new far side data will allow much faster detection of solar storms which in turn will enable faster predictions of space weather which potentially can severely impact sensitive technological infrastructure on Earth and throughout the solar system.
Until now, we had to wait about two weeks until the rear side active regions of the sun rotated into our view on the front side. But no longer. On average the sun rotates in about 27 days – faster at the equator and slower at the poles.
“We will now be able to detect the coronal mass ejections, or CMEs as they happen on the far side instead of waiting until they rotate around with no forewarning. The magnetic storms with energetic particles blast out at varying speeds of about 700 to 1000 km/sec and can reach Earth in one to three days,” said Gurman.
These magnetic storms are a threat to air traffic control of airliners, can disrupt the power grip, damage communications systems, space satellites in Earth orbit and around the solar system, effect other sensitive electronics systems and also harm astronauts working aboard the International Space Station.
STEREO is comprised of two nearly identical STEREO spacecraft – dubbed STEREO Ahead and STEREO Behind –orbiting around our Sun. One probe – B – trails Earth around the sun and moves a bit slower; the other one – A – leads the Earth traveling slightly faster.
Each probe images half of the suns sphere and broadcasts the data back to Earth continuously, 24 hours each day. STEREO’s solar telescopes are tuned to four different wavelengths of extreme ultraviolet radiation (171, 195, 284, 304 Å) selected to trace key aspects of solar activity such as flares, tsunamis and magnetic filaments.
“The images are converted into a spherical projection by researchers on the science teams,” said Gurman. An international group of scientific institutions and governments from the U.S., UK, France, Germany, Belgium, Netherlands and Switzerland designed and built STEREO’s science imaging and particle detecting instruments.
The two probes have been slowly separating in opposite directions at about 45 degrees per year ever since they were launched together aboard a Delta II rocket on October 25, 2006 from Cape Canaveral Air Force Station (CCAFS) in Florida.
After hurtling past the moon, the solar powered spacecraft – weighing some 600 kg – were flung into solar orbit on opposite sides of the Earth and have been moving away from Earth and apart from each other. In this way the wedge of unseen solar territory has been diminishing as the probes gain more complete coverage of the sun, thus enabling us to formulate a more complete understanding of the solar environment.
STEREO stands for Solar TErrestrial RElations Observatory. Their mission is to provide the very first, 3-D “stereo” images of the sun to study the nature of coronal mass ejections.
The STEREO mission is currently funded until 2013.
“The probes have enough fuel to last 100 years,” said Gurman. “The lifetime limiting factor is the spacecraft electronics and funding. The solar arrays will only gradually degrade over decades.”
NASA/STEREO Reveals the Entire Sun
Launched in October 2006, STEREO traces the flow of energy and matter from the sun to Earth. It also provides unique and revolutionary views of the sun-Earth system. STEREO, when paired with SDO, can now give us the first complete view of the sun’s entire surface and atmosphere
Well … its Super SUNday … for Super Bowl XLV on Feb. 6, 2011
The unlikely pairing of Football and Science face off head to head on Super Bowl SUNday. Millions of television viewers will see NASA’s Robonaut 2, or R2, share the the limelight with the Steelers and the Packers of the NFL. The twin brother of R2 is destined for the International Space Station (ISS) and will become the first humanoid robot in space. It will work side by side as an astronaut’s assistant aboard the space station.
The fearsome looking R2 is set to make a first ever special guest appearance during the FOX Networks Super Bowl pre-game show with FOX sports analyst Howie Long. The pre-game show will air starting at 2 p.m. EST on Feb. 6.
And there’s more.
On Super SUNday Feb. 6, NASA will publish Humankinds first ever image of the ‘Entire Sun’ courtesy of NASA’s twin STEREO spacecraft. And given the stunningly cold and snowy weather in Dallas, the arrival of our Sun can’t come soon enough for the ice covered stadium and football fans. See photos above and below.
The two STEREO spacecraft will reach positions on opposite sides of the Sun on Sunday, Feb. 6 at about 7:30 p.m. in the evening, possibly coinciding with the Super Bowl half time show.
At opposition, the STEREO duo will observe the entire 360 degrees sphere of the Sun’s surface and atmosphere for the first time in the history of humankind.
The nearly identical twin brother of R2 is packed aboard Space Shuttle Discovery and awaiting an out of this world adventure from Launch Pad 39 A at NASA’s Kennedy Space Center (KSC) in Florida. Blast off of the first humanoid robot is currently slated for Feb. 24.
R2 is the most dextrously advanced humanoid robot in the world and the culmination of five decades of wide-ranging robotics research at NASA and General Motors (GM).
This newest generation of Robonauts are an engineering marvel and can accomplish real work with exceptionally dexterous hands and an opposable thumb. R2 will contribute to the assembly, maintenance and scientific output of the ISS
“R2 is the most sophisticated robot in the world,” says Rob Ambrose, Chief of NASA’s Johnson Space Center’s (JSC) Robotics Division.
“We hope R2 should help to motivate kids to study science and space,” Ron Diftler told me in an interview at KSC. Diftler is NASA’s R2 project manager at JSC.
The amazingly dexterity of the jointed arms and hands enables R2 to use exactly the same tools as the astronauts and thereby eliminates the need for constructing specialized tools for the robots –saving valuable time, money and weight.
The robot is loaded with advanced technology including an optimized overlapping dual arm dexterous workspace, series elastic joint technology, extended finger and thumb travel, miniaturized 6-axis load cells, redundant force sensing, ultra-high speed joint controllers, extreme neck travel, and high resolution camera and IR systems.
R2 weighs some 300 pounds and was manufactured from nickel-plated carbon fiber and aluminum. It is equipped with two human like arms and two hands as well as four visible light cameras that provide stereo vision with twice the resolution of high definition TV.
“With R2 we will demonstrate ground breaking and innovative robotics technology which is beyond anything else out there and that will also have real world applications as GM works to build better, smarter and safer cars,” according to Susan Smyth, GM Director of Research and Development.
“Crash avoidance technology with advanced sensors is a prime example of robonaut technology that will be integrated into GM vehicles and manufacturing processes.”
Robonaut 2 flight unit poses with the NASA/GM development team inside the Space Station Processing Facility at KSC in this 360 degree panorama from nasatech.net
I was fortunate to meet R2 and the Robonaut team at KSC. R2 is incredibly life like and imposing and I’ll never forget the chance to shake hands. Although its motions, sounds, illuminated hands and muscular chest gives the unmistakable impression of standing next to a lively and powerful 300 pound gorilla, it firmly but gently grasped my hand in friendship – unlike a Terminator.
So its going to make for a mighty match up some day between the fearsome looking R2 and the NFL players.
Well apparently, R2 and Howie will be making some predictions on which player will win the MVP award and a GM Chevrolet. Stay tuned.
So come back on SUNday Feb. 6 for NASA’s release of the first ever images of our entire Sun from the STEREO twins.
“For the first time in the history of humankind we will be able to see the front and the far side of the Sun … Simultaneously,” Madhulika Guhathakurta told Universe Today. Guhathakurta is the STEREO Program Scientist at NASA HQ.
And the noteworthy event is timed to coincide just perfectly with ‘Super Bowl SUNday’ – Exactly one week from today on Feb. 6 during Super Bowl XLV !
“This will be the first time we can see the entire Sun at one time,” said Dean Pesnell, NASA Solar Astrophysicist in an interview for Universe Today. Pesnell is the Project Scientist for NASA’s Solar Dynamics Observatory at the NASA Goddard Spaceflight Center in Greenbelt, MD.
This remarkable milestone will be achieved when NASA’s two STEREO spacecraft reach position 180 degrees separate on opposite sides of the Sun on Sunday, Feb. 6, 2011 and can observe the entire 360 degrees of the Sun.
“We are going to celebrate by having a football game that night!” Pesnell added in jest.
The nearly identical STEREO spacecraft – dubbed STEREO Ahead and STEREO Behind – are orbiting the sun and providing a more complete picture of the Suns environment with each passing day. One probe follows Earth around the sun; the other one leads the Earth.
STEREO is the acronym for Solar TErrestrial RElations Observatory. Their mission is to provide the very first, 3-D “stereo” images of the sun to study the nature of coronal mass ejections.
Today, (Jan 30) the twin STEREO spacecraft are 179.1 degrees apart and about 90 degrees from Earth, and thus virtually at the midpoint to the back of the sun. See the orbital location graphics above and below.
Both probes were flung into space some four years ago and have been hurtling towards this history making date and location ever since. The wedge of unseen solar territory has been declining.
As the STEREO probes continue flying around to the back side of the sun, the wedge of unseen solar territory on the near side will be increasing and the SDO solar probe will play a vital gap filling role.
“SDO provides the front side view of the sun with exquisite details and very fast time resolution,” Gutharka told me. For the next 8 years, when combined with SDO data, the full solar sphere will still be visible.
The solar probes were launched together aboard a Delta II rocket from Launch Complex 17B at Cape Canaveral Air Force Station (CCAFS) in Florida on October 25, 2006. See Launch Video and Photos below.
Whole Solar Sphere A Goldmine for Science
I asked Pesnell and Guhathakurta to explain why this first ever whole Sun view is a significant scientific milestone.
“Until now there has always been an unseen part of the Sun,” Pesnell explained. “Although that unseen part has always rotated into view within a week or two, a global model must include all of the Sun to understand where the magnetic field goes through the surface.”
“Also, from the Earth we can see only one pole of the Sun at a time, while with STEREO we can see both poles at the same time.
“The next few years of overlapping coronal images will be a goldmine of information for predicting space weather at the Earth and understanding of how the Sun works. It is like getting the GOES images of the Earth for the first time. We haven’t missed a hurricane since, and now we won’t miss an active region on the Sun,” said Pesnell.
How will the science data collected be used to understand the sun and its magnetic field?
“Coronal loops trace out the magnetic field in the corona,” Pesnell elaborated. “Understanding how that magnetic field changes requires seeing where on the surface each loop starts and stops.”
Why is it important to image the entire Sun ?
“Once images of the entire Sun are available we can model the entire magnetic field of the Sun. This has become quite important as we are using STEREO and SDO to study how the entire magnetic field of the Sun reacts to the explosions of even small flares.”
“By seeing both poles we should be able to understand why the polar magnetic field is a good predictor of solar activity,” said Pesnell.
“Seeing both sides will help scientists make more accurate maps of global coronal magnetic field and topology as well as better forecasting of active regions – areas that produce solar storms – as they rotate on to the front side. Simultaneous observations with STEREO and SDO will help us study the sun as a complete whole and greatly help in studying the magnetic connectivity on the sun and sympathetic flares, ” Guhathakurta amplified.
What is the role and contribution of NASA’s SDO mission and how will SDO observations be coordinated with STEREO?
“As the STEREO spacecraft drift around the Sun, SDO will fill in the gap on the near of the Sun,” explained Pesnell. “For the next 4 or more years we will watch the increase in sunspots we call Solar Cycle 24 from all sides of the Sun. SDO has made sure we are not doing calibration maneuvers for a few days around February 6.”
“On Feb 6th we will view 100% of the sun,” said Guhathakurta.
At a press conference on Feb. 9, 2011, NASA scientists will reveal something that no one has even seen – The first ever images of ‘The Entire Sun’. All 360 degrees
STEREO spacecraft location map Caption: Positions of STEREO A and B for 31-Jan-2011 05:00 UT. The STEREO spacecraft are 179.2 degrees apart and about 90 degrees from Earth on Jan. 31, 2011. This figure plots the current positions of the STEREO Ahead (red) and Behind (blue) spacecraft relative to the Sun (yellow) and Earth (green). The dotted lines show the angular displacement from the Sun. Units are in A.U. (Astronomical Units). Credit: NASA
STEREO Launch Video
Launch Video Caption: The Delta II rocket lights the evening sky as STEREO heads into space on October 25, 2006 at 8:52 p.m. The Delta II rocket lights the evening sky as STEREO heads into space. STEREO (Solar Terrestrial Relations Observatory) is a multi-year mission using two nearly identical observatories, one ahead of Earth in its orbit and the other trailing behind. The duo will provide 3-D measurements of the sun and its flow of energy, enabling scientists to study the nature of coronal mass ejections and why they happen.
A pair of coronal holes on the Sun newly imaged by NASA’s flagship solar probe, the Solar Dynamics Observatory (SDO) may cause auroral activity here on Earth soon.
The pair of holes were captured in images taken from Jan 9-12, 2011 by SDO’s AIA instrument in the extreme untraviolet (UV). The images – shown above and below – were also made into a cool timelapse video (shown below) of the rotating sun and were released by NASA as “SDO Pick of the Week” for Jan. 14, 2011.
SDO research results on the solar corona are featured as the cover photo and story for the current issue of Science magazine on Jan. 7, 2011. Updated
Coronal holes on the sun’s surface are the source of open magnetic field lines and are areas from which high-speed solar wind particles stream out into space. The fast solar wind travels at approximately 800 km/s (about 1.8 million mph). After traveling through space for a few days the particles will impact the Earth and may spark the formation of some auroral activity for lucky spectators.
The two holes developed over several days. In a video here, one hole is above the suns equator and the other is below. According to a NASA press release, the coronal holes appear dark at the extreme UV wavelength of 193 Angstroms because there is just less of the material – ionized iron- that is being imaged.
2 D Video: A Hole in the Sun’s Corona
Caption: This timelapse video shows a coronal hole, as captured in ultraviolet light by NASA’s Solar Dynamics Observatory around Jan. 10, 2011. Coronal holes are areas of the sun’s surface that are the source of open magnetic field lines that head way out into space. They are also the source regions of the fast solar wind, which “blows” at a relatively steady clip of 1.8 million mph. (No audio). Credit: NASA
3 D Video: Coronal holes from STEREO
Check out this 3 D movie of a coronal hole snapped by NASA’s twin STEREO solar probes orbiting the sun. You’ll need to pull out your red-cyan 3 D anaglyph glasses. First, watch the short movie with you 3 D glasses. Then, I suggest to pause the movie at several intervals for a longer look. Remember – its red on the left eye.
Caption: This STEREO image features an active region and a coronal hole. The hole is the large dark spot in the middle of the sun. Coronal holes are the source of solar wind and a generator for space weather activity. Credit: NASA
SDO roared to space on February 11, 2010 atop a powerful Atlas V rocket from Cape Canaveral Air Force Station in Florida. Launch photo below.
The billion dollar probe is the “crown jewel” in NASA’s solar fleet and will soon celebrate its first anniversary in space. SDO’s mission is to explore the Sun and its complex interior mechanisms in unprecedented detail. It is equipped with three science instruments (HMI, AIA, and EVE)
For several decades, scientists studying the sun have observed solar flares that appear to occur almost simultaneously but originated in completely different areas on the Sun. Solar physicists called them “sympathetic” flares, but it was thought these near-synchronous explosions in the solar atmosphere were too far apart – sometimes millions of kilometers distant – to be related. But now, with the continuous high-resolution and multi-wavelength observations with the Solar Dynamics Observatory, combined with views from the twin STEREO spacecraft, the scientists are seeing how these sympathetic eruptions — sometimes on opposite sides of the sun — can connect through looping lines of the Sun’s magnetic field.
“The high-quality simultaneous data we received from SDO and the STEREO spacecraft, and our subsequent analysis, enable us to present unambiguous evidence that solar regions up to 160 degrees away are involved in defining the large-scale coronal field topology for flares and CMEs,” said Dr. Carolus Schrijver, who co-presented his team’s findings at the American Geophysical Union meeting in San Francisco.
“From the very first observations with SDO we saw small events seemed to impact large regions of the sun,” said Alan Title of the Solar and Astrophysics Lab at Lockheed Martin, and co-author of the paper, speaking at a press briefing, “but because we are scientists and are sometimes not very clever, we have to sometimes be beaten over the head, and went searching for some kind of causality. It has been in last couple of months where we worked out this picture together.”
The hammer on the head was a series of solar events that took place on August 1, 2010, where nearly the entire Earth-facing side of the Sun erupted in a tumult of activity, with a large solar flare, a solar tsunami, multiple filaments of magnetism lifting off the solar surface, radio bursts, and half a dozen coronal mass ejections (CMEs).
SDO, which launched in February of this year, along with the two Solar Terrestrial Relations
Observatory (STEREO) spacecraft — were ideally positioned to capture both the action on the Earth-facing side of the Sun, and most activity around the backside, leaving a wedge of only 30 degrees of the solar surface unobserved.
SDO’s Atmospheric Imaging Assembly (AIA) continuously observes the full solar corona and can trace perturbations over long distances, even if short-lived. The STEREO spacecraft were able to provide perspectives on activity on most of the “back side” of the Sun, and perhaps most importantly, SDO’s Helioseismic and Magnetic Imager (HMI) provided global magnetic field connections.
As seen in the image above, the looping magnetic field lines connected the various events on August 1. Subsequent observations have revealed similar events.
“The magnetic field lines connect to other flares and other major events, with the eruptions and flares frequently coupled across large distances,” said Schrijver. “Previously, we had been looking for the cause of explosions just in the regions from where the explosions were coming from. That might be a good way to do it, but these observations show another aspect. If we wish to know why the flare goes off, we need to know not just properties of region but also a large fraction of the solar surface, in fact sometimes not even part we can see. So maybe reason we had difficulty figuring this out was that we were not seeing everything. We have to expand our view and look at everything.”
Title compared finally figuring out that these near synchronous events are related to how scientists finally figured out continental drift. “Everyone could see how Africa and South America could have once fit together, but no one could imagine the physical processes that could make that happen,” he said, “but all of a sudden someone measured it and figured out sea floor spreading and it made perfect sense.”
In response to a question of whether the magnetic field on the Sun has areas similar to fault lines on the Earth where magnetic lines emerge repeatedly, Schrijver told Universe Today that the magnetic field lines come from the deep within the solar interior, but why it chooses to emerge in certain areas repeatedly is a mystery. “There are successive nests, where they come up one after another, or preferred regions,” he said, but our details on this are fairly weak. Most of time we don’t know where magnetic field lines will emerge from the sun.”
Title said heliophysics research is still in its infancy, but the new resources SDO provides might bring a new era in this area of study.
“We’ve reached a turning point in our ability to forecast space weather,” said Title. “We now have evidence that multiple events can be triggered by other events that occur in regions that cannot be observed from Earth orbit. This gives us a new appreciation of why solar flare and CME predictions have been less than perfect. As we seek to understand the causes of eruptive and explosive events that will improve our ability to forecast space weather, it is clear that we must be able to analyze most of the evolving global solar field, if not all of it.”
Nowhere in the Solar System are conditions more extreme than the Sun. Every second it converts millions of tons of matter into energy to create the intense levels of heat and light we expect of our local star. Study the Sun in different wavelengths and its violent nature can really become apparent. The STEREO satellite has been studying the Sun at a wavelength of 304Å and the results support a controversial solar theory.
Coronal Mass Ejections (or CMEs) are common on the Sun and they have a very real impact to us here on Earth. The solar explosions expel trillions of trillions of tons of super hot hydrogen gas into space, sometimes in the direction of the Earth. Traveling at speeds up to 2,000 kilometers per second it takes just a day for the magnetized gas to reach us and on arrival it can induce strong electric currents in the Earth’s atmosphere leading not only to the beautiful auroral displays but also to telecommunication outages, GPS system failures and even disturbances to power grids.
Solar flares, to use their other name, were first observed back in 1859 and since then, scientists have been studying them to try to understand the mechanism that causes the eruption. It has been known for some time that the magnetically charged gas or plasma is interacting with the magnetic field of the Sun but the detail has been at best, elusive.
In 2006, the international satellite STEREO was launched with the objective of continuously monitoring and studying the CMEs as they head toward the Earth and its data has helped scientists at the Naval Research Laboratory (NRL) in Washington, D.C., start to understand the phenomenon.
Using this new data, scientists at the NRL compared the observed activity with a controversial theory that was first proposed by Dr James Chen (also from the NRL) in 1989. His theory suggested that the erupting clouds of plasma are giant ‘magnetic flux ropes’, effectively a twisted up magnetic field line shaped like a donut. The Sun being a vast sphere of gas suffers from differential rotation where the polar regions of the Sun and the equatorial regions all rotate at different speeds. As a direct result of this, the plasma ‘drags’ the magnetic field lines around and the Sun and it gets more and more twisted up . Eventually, it bursts through the surface, taking some plasma with it giving us one of the most dramatic yet potentially destructive events in the Universe.
Dr Chen and a Valbona Kunkel, a doctorate student at George Mason University, applied Dr. Chen’s model to the new data from STEREO and found that the theory agrees with the measured trajectories of the ejected material. It therefore looks like his theory, whilst controversial may have been right all along.
Its strange to think that our nearest star, the Sun, still has secrets. Yet thanks to the work of Dr. Chen and his team, this one seems to have been unraveled and understanding the strange solar explosions will perhaps help us to minimise impact to Earth based technologies in years to come.
Update: Well, it turns out that while it looks like Venus and Mercury are getting pummeled by Coronal Mass Ejections, the geometry might not work out, at least not for every day that is included in the video above. UT reader Steven Janowiecki brought it to my attention that just because Mercury and Venus look close to the Sun doesn’t mean they’re actually in the line of fire, as they could be well behind or in front of the solar storm. I checked with STEREO project scientist Dr. Joseph Gurman, who took a look at the data. He put together a plot for August 14, (see below) and said, “It shows that Mercury and Venus are well to the East (left) of the Sun-earth line. The large CME on the 14th originated from an active region near the west limb of the Sun, and since most CME’s are about 60 degrees of heliolongitude in width on average, it’s unlikely that that event actually passed by Mercury or Venus.” There was one large event, however, on August 7, that appeared likely to be headed in the direction of Mercury and Venus.
So, as it happens sometimes in astronomy, things are not always as they appear, and this exemplifies the challenges of estimating distance in astronomy.
Here’s the rest of the article as it ran originally:
Take a look at these Coronal Mass Ejections (CME) from the first part of August 2010, as seen by the two STEREO spacecraft. Here on Earth, we’ve had some aurorae, a result of the recent solar activity. But this STEREO imagery shows Venus and Mercury were blasted by these CMEs.
STEREO consists of two spacecraft – one ahead of Earth in its orbit, the other trailing behind. With this new pair of viewpoints, scientists are able to see the structure and evolution of solar storms as they blast from the Sun and move out through space.
These movies were taken by SECCHI, a suite of remote sensing instruments on both spacecraft consisting of two white light coronagraphs that make up the Sun Centered Imaging Package (SCIP), as well as a Heliospheric Imager (HI).
SECCHI can follow three-dimensional Coronal Mass Ejections (CMEs) from the Sun’s surface, through the corona and interplanetary medium, to impact at Earth. With these instruments, scientists are getting breakthroughs in understanding the origin and consequences of CMEs, in determining their three-dimensional structure, and more, and perhaps be able to predict space weather. Combining STEREO with the new Solar Dynamics Observatory, we’ll be learning more and more about the Sun in the next few years.
As an example of SDO’s capabilities, here’s an SDO image from earlier today showing the Sun’s limb.