In April and July 2014, the Sun emitted three jets of energetic particles into space, that were quite exceptional: the particle flows contained such high amounts of iron and helium-3, a rare variety of helium, as have been observed only few times before. STEREO observations enabled researchers to determine the sources of these energetic particles.
The outer part of the Sun's atmosphere, the corona, looks pretty smooth, but new deep exposures of the outer corona reveal complex structures. This should make for some interesting observations from the upcoming Parker Solar Probe Mission (to be launched in 2018), which will be flying right through these regions.
Sun-gazing missions SOHO and STEREO watched the return of comet 96P/Machholz when it entered their fields of view between Oct. 25-30. It is extremely rare for comets to be seen simultaneously from two different locations in space, and these are the most comprehensive parallel observations ever taken of this comet.
The STEREO and SOHO Teams are gearing up for a planned visit by one of our favorite celestial wanderers! The comet 96P/Machholz should be in the STEREO field of view October 26-28. SOHO will be seeing it at the same time, giving us simultaneous views of 96P from two different locations in space!
Want to help solar scientists use STEREO data to better understand Coronal Mass Ejections? You can do that, with no previous experience required. The Solar Stormwatch Project is looking for volunteers who want to help analyze these giant solar storms as they move through the solar system. For more info about how to participate check out the Solar Stormwatch web page.
STEREO and SDO observations of the solar poles reveal large scale waves that could help us predict the locations of future solar active regions.
An international science team says NASA's Fermi Gamma-ray Space Telescope has observed high-energy light from solar eruptions located on the far side of the sun, which should block direct light from these events. This apparent paradox is providing solar scientists with a unique tool for exploring how charged particles are accelerated to nearly the speed of light and move across the sun during solar flares. Thanks to the STEREO spacecraft, which were monitoring the solar far side when the eruptions occurred, the Fermi events mark the first time scientists have direct imaging of beyond-the-limb solar flares associated with high-energy gamma rays.
Join us for a series of presentations celebrating STEREO and efforts to predict space weather on the 10th anniversary of STEREO's launch, October 25, at 1:00 pm EDT. A panel of scientists including scientist-astronaut John Grunsfeld will discus how monitoring the Sun from widely different angles simultaneously can provide early warnings of explosive events on the Sun. The event will held at the National Air and Space Museum in Washington DC and will also be streamed on line and archived for future viewing.
Ever since the 1950s discovery of the solar wind - the constant flow of charged particles from the sun - there's been a stark disconnect between this outpouring and the sun itself. As it approaches Earth, the solar wind is gusty and turbulent. But near the sun where it originates, this wind is structured in distinct rays, much like a child's simple drawing of the sun. The details of the transition from defined rays in the corona, the sun's upper atmosphere, to the solar wind have been, until now, a mystery.
NASA has re-established contact with an errant spacecraft. In October 2006, the space agency sent twin satellites into orbit to study the Sun. The satellites follow Earth's orbit around the sun, one ahead of us and one behind: STEREO-A and STEREO-B.
On Aug. 21, 2016, contact was reestablished with one of NASA's Solar Terrestrial Relations Observatories, known as the STEREO-B spacecraft, after communications were lost on Oct. 1, 2014. Over 22 months, the STEREO team has worked to attempt contact with the spacecraft. Most recently, they have attempted a monthly recovery operation using NASA's Deep Space Network, or DSN, which tracks and communicates with missions throughout space.
Solar flares are intense bursts of light from the sun. They are created when complicated magnetic fields suddenly and explosively rearrange themselves, converting magnetic energy into light through a process called magnetic reconnection at least, that's the theory, because the signatures of this process are hard to detect. But during a December 2013 solar flare, three solar observatories captured the most comprehensive observations of an electromagnetic phenomenon called a current sheet, strengthening the evidence that this understanding of solar flares is correct.
On Oct. 1, 2014, NASA lost communication with one of two STEREO missions spacecraft, just as the satellite was about to orbit around the other side of the sun. More than a year's worth of silence later, the spacecraft has finally emerged into a region where it can again receive signals -- and scientists have a plan to get it back.
On Nov. 9, 2015, NASAÕs Solar and Terrestrial Relations Observatory Ahead, or STEREO-A, once again began transmitting data at its full rate. For the previous year, STEREO-A was transmitting only a weak signal or occasionally none at all due to its position almost directly behind the sun. Subsequently, as of Nov. 17, STEREO resumed its normal science operations, which includes transmission of lower-resolution real-time data used by scientists to monitor solar events as well as high-definition, but delayed, images of the sun's surface and atmosphere.
Much like the flapping of a windsock displays the quick changes in wind's speed and direction, called turbulence, comet tails can be used as probes of the solar wind - the constant flowing stream of material that leaves the sun in all directions. According to new studies of a comet tail observed by STEREO, the vacuum of interplanetary space is filled with turbulence and swirling vortices similar to gusts of wind on Earth. Such turbulence can help explain two of the wind's most curious features: its variable nature and unexpectedly high temperatures.
Two teams of researchers led by Nariaki Nitta from the Lockheed Martin Advanced Technology Center in the USA and by Radoslav Buck from the Max Planck Institute for Solar System Research (MPS) in Germany have independently discovered a new solar phenomenon: large-scale waves in the star's atmosphere accompanied by energetic particle emissions rich in helium-3. Helium-3 is a light variety of the inert gas helium. The huge waves may contribute significantly to accelerate the particles into space, the MPS scientists now report in The Astrophysical Journal. Decisive for this discovery were the two spacecraft STEREO A and ACE making it possible to simultaneously observe the Sun from two different directions. In the near future, no such opportunity will arise again.
On July 11, 2015 we received our first images in over three months from NASA's Solar TErrestrial RElations Observatory Ahead spacecraft, or STEREO-A. Since March 24, 2015, STEREO-A has been on the far side of the sun, where it has had to operate in safe mode, collecting and saving data from its radio instrument.
The three-month safe mode period was necessary because of the geometry between Earth, the sun, and STEREO-A. STEREO-A orbits the sun as Earth does, but in a slightly smaller and faster orbit. The orbit ensured that over the course of years, Earth and the spacecraft got out of sync, with STEREO-A ending up on the other side of the sun from Earth, where it could show us views of our star that we couldnÕt see from home. Though the sun only physically blocked STEREO-A from EarthÕs line of sight for a few days, STEREO-A was close enough to the sunÑfrom our perspective -- that from March 24 until July 8, the sun interfered with STEREO-AÕs data transmission signal, making it impossible to interpret.
The IMPACT, PLASTIC, and SECCHI instruments on STEREO Ahead were turned off at 16:00 UT on Friday, 20 March 2015 in preparation for superior solar conjunction. On Tuesday, 24 March, also at 16:00 UT, the STEREO Ahead spacecraft will be reset into a "safe mode" that it will remain in for the next several months until normal operations can be resumed again in July.
The term "superior solar conjunction" is the technical phrase which refers to period when one or the other STEREO spacecraft is on the opposite side of the Sun from Earth. For each spacecraft, there is a period when it is so close to the Sun as seen from Earth that the radio interference from the Sun makes it impossible to communicate at all with the spacecraft. For a few days, it will even be physically blocked by the Sun. Without any possibility of communications, the spacecraft will have to be placed into "safe mode" until contact can be reestablished. Before communications are completely cut off, the spacecraft will start slowly rotating about the axis which points at the Sun. This is done to reduce the load on the reaction wheels which keep the spacecraft pointing stabilized. All the science instruments will be turned off, with the sole exception of the radio instrument SWAVES which will stay on to record beacon mode data on the recorder for eventual playback in November 2015. Technical and safety considerations prevent the other instruments from being on during this time.
STEREO-A is now on the other side of the Sun, over 290 million km (180 million miles) away (See Where is STEREO? ). Recently, a new planet has appeared in the field of view of it sun-pointed instruments: Earth. You can see Earth and Mercury in this movie from STEREO Ahead's SECCHI Cor2 coronagraph. The location of the Sun (hidden by a disk so we can see its faint outer atmosphere) is shown with the white circle. The horizontal lines through the two planets are due to saturation effects in the detector - the planets are brighter than the solar features the cameras were designed for.
Communications with the STEREO Behind spacecraft were interrupted on October 1, 2014 immediately after a planned reset of the spacecraft performed as part of a test of solar conjunction operations. The spacecraft telemetry indicated an anomaly in the guidance and control system, but this is still being evaluated. No further communications have been successful since Oct. 1st. Follow this link for more information.
The STEREO Ahead spacecraft has already successfully tested the transition into and out of solar conjunction operations. Actual solar conjunction operations will take place between March 22 and July 14, 2015. STEREO Ahead continues to operate nominally, and is currently providing our only views of the far side of the sun.
Attempts to reestablish communications with the STEREO Behind spacecraft are ongoing.
Launched in 2006, the STEREO mission achieved its prime science goals within the two-year prime mission, but continues to explore solar and heliospheric activity through the current solar maxmimum and beyond.
Since February 2011, the two spacecraft of NASA's STEREO mission have been providing scientists with unprecedented views of the far side of the sun. Placed in orbits that allow their perspective to change over the eight years since their launch in 2006, the satellites are about to enter a new phase of their journey: a time when the bright light and heat of the sun will stand in the way of sending data back to Earth.
Understanding the sun from afar isn't easy. How do you figure out what powers solar flares - the intense bursts of radiation coming from the release of magnetic energy associated with sunspots Ð when you must rely on observing only the light and particles that make their way to near-Earth's orbit?
Surrounding the sun is a vast atmosphere of solar particles, through which magnetic fields swarm, solar flares erupt, and gigantic columns of material rise, fall and jostle each other around. Now, using observations from NASA's STEREO, scientists have found that this atmosphere, called the corona, is even larger than previously thought.
Time and again, the sun hurls energetic charged particles into space in violent eruptions. At the same time, a continuous stream of particles, the solar wind, escapes from its surface. Numerous space probes in the EarthÕs vicinity monitor how this matter propagates through space. However, until STEREO this information never showed the whole picture.
On July 22, 2012, a massive cloud of solar material erupted off the sun's right side, zooming out into space and passing one of NASA's two Solar Terrestrial Observatory (STEREO) spacecraft along the way. Scientists clocked this giant cloud, known as a coronal mass ejection, or CME, as traveling over 3000 kilometers per second as it left the Sun.
Four comets are now visible using STEREO-A's HI2, although you'll have to look very closely to see them all.
You can follow the progress of MAVEN and STEREO with the STEREO orbit tool by checking off MAVEN at the bottom of the page.
Astronomers are eagerly awaiting the arrival of Comet ISON, which will pass within just 2.7 solar radii from Sun center on November 28, 2013 (U.S. Thanksgiving). Although comets are unpredictable, Comet ISON has the potential to be a major comet. If so, STEREO should have a spectacular view. To assist with planning for this event, a new web page has been put together describing Comet ISON's orbit, and how the comet will be seen by STEREO's telescopes, and those on other solar observatories.
The STEREO Behind spacecraft has now moved far enough in its orbit for Earth to enter the HI1-B field-of-view. Earth has been visible in the HI2 telescopes since launch, but this is the first time it's been visible in either of the HI1 telescopes, which image areas closer to the Sun. This is happening because the STEREO spacecraft are moving closer to the points in their orbits at which they will be directly opposite Earth on the other side of the Sun.
On July 23, 2012, a massive cloud of solar material erupted off the sun's right side, zooming out into space, passing one of NASA's STEREO spacecraft along the way. Using the STEREO data, scientists at NASA's Goddard Space Flight Center in Greenbelt, Md. clocked this giant cloud, known as a coronal mass ejection, or CME, as traveling between 1,800 and 2,200 miles per second as it left the sun.
A massive sunspot region facing Earth - known as 1520 - has unleashed a large solar flare. NOAAÕs Space Weather Prediction Center says the flare is rated an X1.4. This type of flare is considered ÒstrongÓ and can cause a blackout of high frequency radio communication on the sunlit side of Earth for one to two hours.
NOVA SAGITTARII 2012 = PNV J17452791-2305213, becomes apparent in STEREO HI1B imager across 20120420-23.
One day in the fall of 2011, Neil Sheeley, a solar scientist at the Naval Research Laboratory in Washington, D.C., did what he always does Ð look through the daily images of the sun from NASA's Solar Dynamics Observatory (SDO).
But on this day he saw something he'd never noticed before: a pattern of cells with bright centers and dark boundaries occurring in the sun's atmosphere, the corona. These cells looked somewhat like a cell pattern that occurs on the sun's surface -- similar to the bubbles that rise to the top of boiling water -- but it was a surprise to find this pattern higher up in the corona, which is normally dominated by bright loops and dark coronal holes.
Twin Solar Spacecraft Take First Complete Image of Far Side of Sun
Some people have noticed a strange triangular or diamond-shape "object" entering the field-of-view of the HI2 telescope on STEREO Behind around December 26, 2011. You can see the feature in question in this movie moving from right-to-left, just above the trapezoidal occulter on the right side of the image, and more clearly in this close-up movie. What is this?
The two STEREO spacecraft now sit on opposite sides of the sun providing a view of the latest solar activity for the entire solar system.
On October 25, 2006 a Delta II rocket launched from Cape Canaveral carrying two nearly identical spacecraft. Each satellite was one half of a mission entitled Solar TErrestrial RElations Observatory (STEREO) and they were destined to do something never done before - see the entire sun simultaneously.
For the first time, a spacecraft far from Earth has turned and watched a solar storm engulf our planet. The movie, released today during a NASA press conference, has galvanized solar physicists, who say it could lead to important advances in space weather forecasting.
Combined data from the STEREO and ACE spacecraft are being used to study the structure of a CME in unprecedented detail, showing considerable evolution in the CME's internal structure as it moves from the Sun to Earth.
Researchers have discovered 122 new eclipsing binary stars and observed hundreds more variable stars in an innovative survey using NASA's two STEREO solar satellites.
On February 6, 2011, NASA released the first ever images of the entire Sun, using a combination of STEREO images together with data from the Solar Dynamics Observatory. This never before seen view was made possible by STEREO's unique viewing geometry.
For the past 4 years, the two STEREO spacecraft have been moving away from the Earth and gaining a more complete picture of the sun. On February 6, 2011, NASA will reveal the first ever images of the entire sun and discuss the importance of seeing all of our dynamic star.
For the first time scientists have used data analysed by the public to make a real-time prediction of a solar storm that should reach Earth on Monday 13 December, thanks to the Solar Stormwatch web project.
The initiative, launched in February by the Royal Observatory, Greenwich (ROG), in partnership with the STFC Rutherford Appleton Laboratory and the Zooniverse citizen science project, makes it possible for anyone with an internet connection to get involved in the latest solar research by helping to spot and track storms as they erupt from the surface of the Sun. These collective measurements enable scientists to forecast the arrival of storms far enough in advance to issue effective pre-emptive warnings for the first time.
The Sun is much more dynamic than it appears to the naked eye. Intense magnetic fields churn and pummel the SunÕs atmosphere and they store enormous amounts of energy that, when released, can hurl billions of tons of material out into space in eruptions called Coronal Mass Ejections (CMEs) Ð or solar storms.
The latest storm identified by the project is predicted to hit Earth at 07.32 GMT on 13 December. Solar storms have the potential to interfere with communication satellites, upset GPS navigation systems and also pose a health risk to astronauts on the International Space Station. In severe cases they can even knock out entire power grids causing widespread disruption here on Earth. On a gentler note, the particles making up a solar storm can produce beautiful displays of the Northern and Southern Lights as they collide with the Earth's upper atmosphere. Scientists are not overly concerned about the effects of the current storm, but the early warning provided by Solar Stormwatch will allow precautionary measures to be put in place.
Illustration of the positions of the two STEREO spacecraft show that they attain 180 degrees of separation in Feb. 2011, thus allowing the world to see the entire Sun for the first time.
Scientists from Boston University's Center for Space Physics (CSP) reported the presence of a comet-like tail in images of the planet Mercury taken by STEREO, in a presentation given September 22, 2010 at the European Planetary Science Congress (EPSC) meeting in Rome.
Solar researchers have used a novel set of techniques using STEREO data that allow them to watch the acceleration and deflection of coronal mass ejections with unprecedented precision.
On August 1st around 0855 UT, Earth orbiting satellites detected a C3-class solar flare. The origin of the blast was Earth-facing sunspot 1092. C-class solar flares are small (when compared to X and M-class flares) and usually have few noticeable consequences here on Earth besides aurorae. This one has spawned a coronal mass ejection heading in Earth's direction.
When a coronal mass ejection (CME) erupts from the Sun, movies in extreme ultraviolet light often show enormous waves, spreading over a large area on the solar surface, just as tsunamis travel far from the original seismic event. Now STEREO data have been used to show that these waves are the footprints of giant domes that spread upward into the corona as well as outward across the surface.
Using instruments aboard NASA's twin STEREO spacecraft, four post-doctoral fellows at UC Berkeley's Space Sciences Laboratory were able to track the comet as it approached the Sun (Mar. 11-12, 2010) and estimate an approximate time and place of impact.
NASA's new Solar Dynamics Observatory may be getting all the press this week for its retina-searing first pictures of the sun. But two old sun-observing warhorses recently showed they're not quite ready for pasture yet.
STEREO featured live and on-line in a new exhibition at the UK National Maritime Museum
Solar scientists need you! Help them spot explosions on the Sun and track them across space to Earth. Your work will give astronauts an early warning if dangerous solar radiation is headed their way. And you could make a new scientific discovery.
We have investigated, and determined that these are artifacts caused by an interaction between the high compression factors used for the beacon data, and cosmic ray events on the detector. Our discussion of image artifacts has been updated to include this phenomenon. Another factor which has contributed to this issue has been the recent delay in receiving the full resolution images from the spacecraft. This was caused by a server problem at the Deep Space Network, and has now been resolved.
A new free application for iPhones lets you access up-to-date global views of the Sun from STEREO along with solar activity alerts and other features. With this application, you can interactively view the Sun from any angle, and zoom in on features of interest, based on combined images from both STEREO spacecraft.
STEREO has made possibly the first 3D measurements of a solar jet. Jets are columns of super hot plasma (hot ionized gases at over a million degrees) which shoot out from the sun over the course of just a few minutes - this one reached velocities of 300 km/s (650,000 miles/hour). It was over 10,000 kilometers high and nearly half as wide as the Earth.
STEREO observed it from two points of view 11 degrees apart. With these images it could be clearly seen that the jet was twisted. This twist is important. It agrees with models of jets in which they are caused by the twisting of magnetic field lines. Highly twisted magnetic fields eventually become unstable, much like an over-wound spring. When the writhing fields come into contact with nearby untwisted fields that extend into the solar wind, the twist is transferred to those very long field lines. The twist then rapidly leaves the Sun, pushing the plasma outward at high speed.
The figure shows a sequence of three 195 A difference images obtained by the EUVI instrument on STEREO taken on May 19, 2007. The images show a tsunami blasting through the Sun's atmosphere at millions of kilometers per hour.