A year ago, researchers from the IBEX mission – NASA’s Interstellar Boundary Explorer – announced the discovery of an unexpected bright band or ribbon of surprisingly high energy emissions at the boundary between our solar system and interstellar space. Now, after a year of observations, scientists have seen vast changes, including an unusual knot in the ribbon which appears to have ‘untied.’ Changes in the ribbon — a ‘disturbance in the force,’ so to speak, along with a shrunken heliosphere, may be allowing galactic cosmic rays to leak into our solar system. Continue reading “Mysterious Ribbon at Edge of Solar System is Changing”
“Now we know what it would look like if Jupiter and the sun had a child,” joked Ralph Seguin of the Lockheed-Martin Solar and Astrophysics Lab, trying to explain this weird image. So, just what is it? Some people have been calling it “Sunpiter,” since parts of it looks like the Sun, and other parts look like Jupiter. It really is the Sun, as seen by the Solar Dynamics Observatory, which was having a tough day. Normally, SDO gets a great view of the Sun, but the spacecraft occasionally gets its view blocked by the Earth, in a unusual kind of eclipse. This image is a composite of multiwavelength images and a magnetogram taken by SDO just as the sun was emerging from its daily blackout. “SDO has entered eclipse season,” said Seguin. “Around the time of the equinoxes, the spacecraft, Earth, and sun can line up almost perfectly. Once a day for about an hour, Earth blocks SDO’s view of the sun.” And this is the result.
Magnetograms are computed from a series of images taken over a short time span. The ribbons of color result from Earth’s motion across the sun during the series of exposures. This eclipse season for SDO lasts until October 6, 2010.
A new type of adaptive optics for solar observations has produced some incredible results, providing the most detailed image of a sunspot ever obtained in visible light. A new telescope built by the New Jersey Institute of Technology’s Big Bear Solar Observatory has seen its ‘first light’ using a deformable mirror, which is able to reduce atmospheric distortions. This is the first facility-class solar observatory built in more than a generation in the U.S.
The New Solar Telescope (NST) is located in the mountains east of Los Angeles. It has 97 actuators that make up the deformable mirror. By the summer of 2011, in collaboration with the National Solar Observatory, BBSO will have upgraded the current adaptive optics system to one utilizing a 349 actuator deformable mirror. The telescope has a 1.6 m clear aperture, with a resolution covering about 50 miles on the Sun’s surface.
The NST will be the pathfinder for an even larger ground-based telescope, the Advanced Technology Solar Telescope to be built over the next decade. Philip R. Goode from NJIT is leading a partnership with the National Solar Observatory (NSO) to develop a new and more sophisticated kind of adaptive optics, known as multi-conjugate adaptive optics. This new optical system will allow the researchers to increase the distortion-free field of view to allow for better ways to study these larger and puzzling areas of the Sun, and a 4-meter aperture telescope will be built in the next decade.
The Sun’s corona is threaded with a complex network of magnetic fields, and this amazing new image from the Solar Dynamics Observatory shows the magnetic field lines associated with a coronal hole that is now turning to face Earth. This map is from data taken on August 20, 2010 by the Helioseismic and Magnetic Imager instrument (HMI). The magnetic field lines are color coded: white lines show fields that are closed, not releasing solar wind, and gold lines show open fields, letting solar wind escape. Understanding these magnetic fields is important because it is thought that solar storms and flares, which can affect us here on Earth, result from changes in the structure and connections of these fields.
Coronal holes are large regions in the corona that are darker, less dense and cooler than surrounding areas. The open structure of their magnetic field allows a constant flow of high-density plasma to stream out of the holes. There is an increase in the intensity of the solar wind effects on Earth when a coronal hole faces.
During a solar minimum, such as the one from which the Sun is just emerging, coronal holes are mainly found at the Sun’s polar regions, but they can be located anywhere on the sun during solar maximum. The fast-moving component of the solar wind is known to travel along open magnetic field lines that pass through coronal holes.
Scientists are finding out that much of the structure of the Sun’s corona is shaped by the magnetic field. Although it varies over time and from place to place on the Sun, the Sun’s magnetic field can be very strong. Inside sunspots, the magnetic field can be several thousand times the strength of the Earth’s magnetic field.
Learn more about magnetic field lines and how SDO’s HMI instrument will help us to better understand the Sun in this video from SDO:
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.
Here’s something we’ve not seen in a long while: five sunspots on the Sun at once. Is the Sun finally waking up from its unusually long and deep solar minimum slumber? While activity on the Sun usually ebbs and flows on a fairly predictable 11-year cycle, this current cycle has been anything but conventional. In 2009, there were 260 days (71% of the time) that the Sun was ‘spotless,’ but now in 2010 so far, the Sun has had spots been spotless for only 35 days. With the last solar maximum occurring in 2001, maybe the Sun is just now ramping up to the next maximum, which is set for 2013. Recent solar flares on August 1 and 7, and now these sunspots may be signaling that the Sun is “throwing off the covers” and starting to wake up.
This marvelous image from the Solar Dynamics Observatory shows that at about 8:55 UTC on August 1, a measurable solar flare triggered an event known as a coronal mass ejection (CME). This is where the “atmosphere” of the Sun sends out a burst of energized plasma. In this case, nearly the entire Earth-facing side of the Sun was involved.
The High Energy Astrophysics Picture of the week Page used that great “covers” analogy:
The Sun, after a long sleep, is finally waking up. And like any irascible sleeper vigorously throwing off the covers. In this case the covers are composed of high-energy electrons and protons being shot out into space at a tremendous rate. The image above, obtained by the Solar Dynamics Observatory on August 1, shows almost the entire earth-facing side of the sun erupting at once. In this extreme ultraviolet image you can see evidence of extremely ultraviolent activity: a C3-class solar flare (white area on upper left), a solar tsunami (upper right), multiple filaments of magnetism lifting off the stellar surface, large-scale shaking of the solar corona, and a coronal mass ejection. The coronal mass ejection, or CME, showered the earth with charged particles, producing spectacular aurora (northern lights) as far south as Iowa and Telemark, Norway.
And another CME on August 7 has not yet triggered a major geomagnetic storm, but high latitude sky watchers should take a look tonight, just in case.
The Harvard Smithsonian Center for Astrophysics released the latest information on the July 31/August 1 activity on the Sun that is just now reaching Earth. They predict we’ll have multiple opportunities for a display of the Northern Lights over the next two days. The latest word from the solar scientists is that the Sun erupted not just once, but four times. All four coronal mass ejections are headed toward Earth.
Space weather forecasts are even more challenging than regular weather forecasts, said Dr. Leon Golub, and a coronal mass ejection is like a hurricane: it’s large and fuzzy, and doesn’t always move at the same speed. Currently, the estimated arrival times are:
Wednesday, Aug. 4 – 3:00 a.m. EDT (0700 GMT on Aug. 5; aurorae not visible in daylight)
Wednesday, Aug. 4 – 1:00 p.m. EDT (1600 GMT, again the daylight issue)
Wednesday, Aug. 4 – 8:00 p.m. EDT (0000 GMT on Aug. 5)
Thursday, Aug. 5 – 2:00 a.m. EDT (0600 GMT)
Any one of these events may or may not generate an aurora. It depends on details like magnetic field orientation. If the magnetic field in the oncoming solar plasma is directed opposite Earth’s magnetic field, the result could be spectacular aurorae. If the fields line up, the coronal mass ejection could slide past our planet with nary a ripple.
The Center for Astrophysics suggested these two resources:
Map of current auroral activity
Chart of proton flux (watch for the numbers to go up as each wave arrives)
Have you been checking out the Solar Dynamics Observatory website and seeing all the amazing, high resolution images of our closest star? If not, you should. Above is a great new video of SDO’s capabilities and latest images. If you want to see what the Sun looks like right now, go to SDO’s homepage. And here’s a link to the SDO image browser where you can see the different images in different wavelengths from the AIA (Atmospheric Imaging Assembly) and HMI (Helioseismic and Magnetic Imager). If you choose the date range option, you can see a “movie” of the Sun’s activity. For example, check out the enormous coronal hole in the northern hemisphere seen last week in AIA 193 (date range 6/28 to 7/3), allow all the images to download and then press “Play.” Completely awesome. The SDO website should be part of your daily internet routine!
Already, the Solar Dynamics Observatory, or SDO, has taken over 5 million images, and the firehose of data and spectacular images is allowing solar scientists to begin understanding the dynamic nature of solar storms. With SDO, scientists are seeing that even minor solar events can have large effects across the Sun. “In essence, we are watching the butterfly effect in action on the Sun,” said Dean Pesnell, SDO project scientist.
The Atmospheric Imaging Assembly (AIA), one of three instruments aboard SDO, records high-resolution full-disk images of the Sun’s corona and chromosphere in more channels and at a higher rate than ever before. “This will allow us to zoom in on small regions and see far more detail in time and space, and zoom in on any part we want,” said Pesnell. “By looking at entire Sun we can see how one part of the Sun affects another. You can then zoom in to measure the changes in great detail.”
Shortly after AIA opened its doors on March 30, scientists observed a large eruptive prominence on the sun’s edge, followed by a filament eruption a third of the way across the star’s disk from the eruption.
“Even small events restructure large regions of the solar surface,” said Alan Title, AIA principal investigator at Lockheed Martin Advanced Technology Center. “It’s been possible to recognize the size of these regions because of the combination of spatial, temporal and area coverage provided by AIA.”
At the 216th American Astronomical Society meeting this week, Title said that some of the initial data from SDO is providing maps of magnetic fields and movies that are giving scientists some confidence in trying to decipher the cause and effect of solar storms
AIA observed a number of very small flares that have generated magnetic instabilities and waves with clearly-observed effects over a substantial fraction of the solar surface. The instrument is capturing full-disk images in eight different temperature bands that span 10,000 to 36-million degrees Fahrenheit. This allows scientists to observe entire events that are very difficult to discern by looking in a single temperature band, at a slower rate, or over a more limited field of view.
Solar storms produce disturbances in electromagnetic fields that can induce large currents in wires, disrupting power lines and causing widespread blackouts here on Earth. The storms can interfere with global positioning systems, cable television, and communications between ground controllers and satellites and airplane pilots flying near Earth’s poles. Radio noise from solar storms also can disrupt cell phone service.
To help scientists and the public to understand and have access to the large amount of data being returned by SDO, the science team has built some tools to help communicate the data.
New websites will help researchers find data sets relative to their topics of interest and provide an overview to the casual observer.
“SDO generates as much data in a single day as the TRACE mission produced in five years,” said Neal Hurlburt from SDO mission, from Lockheed Martin. “We want to share it with the public, but we want to do it in an effective way, so we developed the Heliophysics Events Knowledgebase (HEK) and the Sun Today Website.”
The Sun Today website displays the current state of events on the sun. These can guide researchers and others to more detailed descriptions and access to associated SDO data.
HEK includes the Event and Coverage Registries (HER, HCR), Inspection & Analysis Tools, Event Identification System and Movie Processing. Event services enable web clients to interact with the HEK.
There is also a tutorial on how to work with the data, and extract images and movies from the SDO data.
Images and data are starting to roll in from the Solar Dynamics Observatory, and the images are nothing short of stunning. So, the SDO website has started a couple of new image gallery features, which will provide a “best of” weekly fix without overloading your Sun senses (and no sunscreen needed!) The first one is Pick of the Week. The image above is the first “pick” and what a pick it is! This SDO close-up shows a filament and active region on the Sun, taken in extreme UV light on May 18, 2010. It shows a dark and elongated filament hovering above the Sun’s surface, with bright regions beneath it. The filaments are cooler clouds of gas that are suspended by tenuous magnetic fields that are often unstable and commonly erupt. This one is estimated to be at least 60 Earth diameters long (about 805,000 km, or 500,000 miles). Wowza!
Hot Shots will feature some great looking flares. This image from the Atmospheric Imaging Assembly (AIA) instrument shows a solar eruption and a flare. The dark regions show the site of evacuated material from the eruption, and the large magnetic loops were formed during the flare. AIA takes images of the solar atmosphere in multiple wavelengths to study link changes in the surface and how they related to interior changes in the Sun. AIA takes images of the Sun in 10 wavelengths every 10 seconds.