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. The mission observed the sun in 3-D for the first time in 2007. In 2009, the twin spacecraft revealed the 3-D structure of coronal mass ejections which are violent eruptions of matter from the sun that can disrupt communications, navigation, satellites and power grids on Earth.Seeing?the whole sun front and back simultaneously will enable significant advances in space weather forecasting for Earth and for planning for future robotic and manned spacecraft missions throughout the solar system.These views are the result of observations by NASA's two Solar TErrestrial Relations Observatory (STEREO) spacecraft. The duo are on diametrically opposite sides of the sun, 180 degrees apart. One is ahead of Earth in its orbit, the other trailing behind.For the STEREO Sun360 Teaser, go here.For the full visualization showing STEREO's path go here.For the visualization showing STEREO's increasing coverage of the sun (visual 3) go here.For animations from the STEREO Teaser and stages of coverage, go here.For animations showing STEREO's 3D coverage of a CME go here. ||

Heliophysics is a term to describe the study of the Sun, its atmosphere or the heliosphere, and the planets within it as a system. As a result, it encompasses the study of planetary atmospheres and their magnetic environment, or magnetospheres. These environments are important in the study of space weather.As a society dependent on technology, both in everyday life, and as part of our economic growth, space weather becomes increasingly important. Changes in space weather, either by solar events or geomagnetic events, can disrupt and even damage power grids and satellite communications. Space weather events can also generate x-rays and gamma-rays, as well as particle radiations, that can jeopardize the lives of astronauts living and working in space.This visualization tours the regions of near-Earth orbit; the Earth's magnetosphere, sometimes called geospace; the region between the Earth and the Sun; and finally out beyond Pluto, where Voyager 1 and 2 are exploring the boundary between the Sun and the rest of our Milky Way galaxy. Along the way, we see these regions patrolled by a fleet of satellites that make up NASA's Heliophysics Observatory Telescopes. Many of these spacecraft do not take images in the conventional sense but record fields, particle energies and fluxes in situ. Many of these missions are operated in conjunction with international partners, such as the European Space Agency (ESA) and the Japanese Space Agency (JAXA).The Earth and distances are to scale. Larger objects are used to represent the satellites and other planets for clarity.Here are the spacecraft featured in this movie:Near-Earth Fleet:Hinode: Observes the Sun in multiple wavelengths up to x-rays. SVS pageRHESSI : Observes the Sun in x-rays and gamma-rays. SVS pageTRACE: Observes the Sun in visible and ultraviolet wavelengths. SVS pageTIMED: Studies the upper layers (40-110 miles up) of the Earth's atmosphere.FAST: Measures particles and fields in regions where aurora form.CINDI: Measures interactions of neutral and charged particles in the ionosphere. AIM: Images and measures noctilucent clouds. SVS pageGeospace Fleet:Geotail: Conducts measurements of electrons and ions in the Earth's magnetotail. Cluster: This is a group of four satellites which fly in formation to measure how particles and fields in the magnetosphere vary in space and time. SVS pageTHEMIS: This is a fleet of five satellites to study how magnetospheric instabilities produce substorms. SVS pageL1 Fleet: The L1 point is a Lagrange Point, a point between the Earth and the Sun where the gravitational pull is approximately equal. Spacecraft can orbit this location for continuous coverage of the Sun.SOHO: Studies the Sun with cameras and a multitude of other instruments. SVS pageACE: Measures the composition and characteristics of the solar wind. Wind: Measures particle flows and fields in the solar wind. Heliospheric FleetSTEREO-A and B: These two satellites observe the Sun, with imagers and particle detectors, off the Earth-Sun line, providing a 3-D view of solar activity. SVS pageHeliopause FleetVoyager 1 and 2: These spacecraft conducted the original 'Planetary Grand Tour' of the solar system in the 1970s and 1980s. They have now travelled further than any human-built spacecraft and are still returning measurements of the interplanetary medium. SVS pageThis enhanced, narrated visualization was shown at the SIGGRAPH 2009 Computer Animation Festival in New Orleans, LA in August 2009; an eariler version created for AGU was called NASA's Heliophysics Observatories Study the Sun and Geospace. ||

NASA's STEREO spacecraft and new data processing techniques have succeeded in tracking space weather events from their origin in the Sun's ultrahot corona to impact with the Earth 93 million miles away, resolving a 40-year mystery about the structure of the structures that cause space weather: how the structures that impact the Earth relate to the corresponding structures in the solar corona.Despite many instruments that monitor the Sun and a fleet of near-earth probes, the connection between near-Earth disturbances and their counterparts on the Sun has been obscure, because CMEs and the solar wind evolve and change during the 93,000,000 mile journey from the Sun to the Earth.STEREO includes "heliospheric imager" cameras that monitor the sky at large angles from the Sun, but the starfield and galaxy are 1,000 times brighter than the faint rays of sunlight reflected by free-floating electron clouds inside CMEs and the solar wind; this has made direct imaging of these important structures difficult or impossible, and limited understanding of the connection between space storms and the coronal structures that cause them.Newly released imagery reveals absolute brightness of detailed features in a large geoeffective CME in late 2008, connecting the original magnetized structure in the Sun's corona to the intricate anatomy of an interplanetary storm as it impacted the Earth three days later. At the time the data were collected, in late 2008, STEREO-A was nearly 45 degrees ahead of the Earth in its orbit, affording a very clear view of the Earth-Sun line.For the press conference Visual 1, a visualization of the STEREO orbits and the 2008 CME, go here.For Visual 7, a CME and reconnection animation, go here.For Visual 8, footage of the October 2003 solar storms, go here. ||

On May 1, 2013, NASA's Solar Dynamics Observatory (SDO) watched as an active region just around the East limb (left edge) of the sun erupted with a huge cloud of solar material—a heated, charged gas called plasma. This eruption, called a coronal mass ejection, or CME, sent the plasma streaming out through the solar system. Viewing the sun in the extreme ultraviolet wavelength of 304 angstroms, SDO provided a beautiful view of the initial arc as it left the solar surface. Such eruptions soon leave SDO's field of view, but other satellites in NASA's Heliophysics fleet can pick them up, tracking such space weather to determine if they are headed toward Earth or spacecraft near other planets. With advance warning, many space assets can be put into safe mode and protect themselves from the effects of such particle radiation.In addition to the images captured by SDO, the May 1, 2013 CME was also observed by the ESA/NASA Solar and Heliospheric Observatory (SOHO). SOHO houses two overlapping coronagraphs—telescopes where the bright sun is blocked by a disk so it doesn't overpower the fainter solar atmosphere—and they both saw the CME continue outward. The LASCO C2 coronagraph shows the region out to about 2.5 million miles. The LASCO C3 coronagraph expands even farther out to around 13.5 million miles. Both of these instruments show the CME as it expands and becomes fainter on its trip away from the sun.NASA's Solar Terrestrial Relations Observatory (STEREO) Ahead satellite saw the eruption from a very different angle. It, along with its twin STEREO Behind, is orbiting at a similar distance as Earth. STEREO-A orbits slightly faster than Earth and STEREO-B orbits slightly slower. Currently, STEREO-A is more than two-thirds of the way to being directly behind the sun, and has a view of the far side of the sun. From this perspective, the CME came off the right side of the sun. STEREO has an extreme ultraviolet camera similar to SDO's, but it also has coronagraphs like SOHO. As a result, using its two inner coronagraphs, it was able to track the CME from the solar surface out to 6.3 million miles.Working together, such missions provide excellent coverage of a wide variety of solar events, a wealth of scientific data—and lots of beautiful imagery.Watch this video on YouTube. ||

August 1972, as NASA scientist Ian Richardson remembers it, was hot. In Surrey, England, where he grew up, the fields were brown and dry, and people tried to stay out of the Sun, indoors and televisions on. But for several days that month, his TV picture kept breaking up. “Do not adjust your set,” he recalls the BBC announcing. “Heat isn’t causing the interference. It’s sunspots.”The same sunspots that disrupted the television signals led to enormous solar flares — powerful bursts of radiation from the Sun — Aug. 4-7 that year. Between the Apollo 16 and 17 missions, the solar eruptions were a near miss for lunar explorers. Had they been in orbit or on the Moon’s surface, they would have sustained dangerous levels of solar radiation sparked by the eruptions. Today, the Apollo-era flares serve as a reminder of the threat of radiation exposure for technology and astronauts in space. Understanding and predicting solar eruptions is crucial for safe space exploration. Almost 50 years since those 1972 storms, the data, technology and resources available to NASA have improved, enabling advancements towards space weather forecasts and astronaut protection — key to NASA’s Artemis program to return astronauts to the Moon.Read more on NASA.gov. ||

Humans have always wanted to learn about the Sun, but our understanding of our favorite star has changed through the centuries. In prepartion for Sun360, when the STEREO spacecrafts will provide the first uninterrupted view of the Sun, this video is a condensed history of how we have studied the Sun over time. ||

On July 23, 2012, a massive cloud of solar material erupted off the sun's right side, zooming out into space. It soon passed one of NASA's Solar Terrestrial Relations Observatory, or STEREO, spacecraft, which clocked the CME as traveling between 1,800 and 2,200 miles per second as it left the sun. This was the fastest CME ever observed by STEREO. Two other observatories – NASA's Solar Dynamics Observatory and the joint European Space Agency/NASA Solar and Heliospheric Observatory — witnessed the eruption as well. The July 2012 CME didn't move toward Earth, but watching an unusually strong CME like this gives scientists an opportunity to observe how these events originate and travel through space. STEREO's unique viewpoint from the sides of the sun combined with the other two observatories watching from closer to Earth helped scientists create models of the entire July 2012 event. They learned that an earlier, smaller CME helped clear the path for the larger event, thus contributing to its unusual speed. Such data helps advance our understanding of what causes CMEs and improves modeling of similar CMEs that could be Earth-directed. ||

Scientists have spotted the iconic surfer's wave rolling through the atmosphere of the sun. This makes for more than just a nice photo-op: the waves hold clues as to how energy moves through that atmosphere, known as the corona. Since scientists know how these kinds of waves — initiated by a Kelvin-Helmholtz instability if you're being technical — disperse energy in the water, they can use this information to better understand the corona. This in turn, may help solve an enduring mystery of why the corona is thousands of times hotter than originally expected.Kelvin-Helmholtz instabilities occur when two fluids of different densities or different speeds flow by each other. In the case of ocean waves, that's the dense water and the lighter air. As they flow past each other, slight ripples can be quickly amplified into the giant waves loved by surfers. In the case of the solar atmosphere, which is made of a very hot and electrically charged gas called plasma, the two flows come from an expanse of plasma erupting off the sun's surface as it passes by plasma that is not erupting. The difference in flow speeds and densities across this boundary sparks the instability that builds into the waves. In order to confirm this description, the team developed a computer model to see what takes place in the region. Their model showed that these conditions could indeed lead to giant surfing waves rolling through the corona. Seeing the big waves suggests they can cascade down to smaller forms of turbulence too. Scientists believe that the friction created by turbulence — the simple rolling of material over and around itself — could help add heating energy to the corona. The analogy is the way froth at the top of a surfing wave provides friction that will heat up the wave. ||

Sungrazing comets are a special class of comets that come very close to the sun at their nearest approach, a point called perihelion. To be considered a sungrazer, a comet needs to get within about 850,000 miles from the sun at perihelion. Many come even closer, even to within a few thousand miles. Being so close to the sun is very hard on comets for many reasons. They are subjected to a lot of solar radiation which boils off their water or other volatiles. The physical push of the radiation and the solar wind also helps form the tails. And as they get closer to the sun, the comets experience extremely strong tidal forces, or gravitational stress. In this hostile environment, many sungrazers do not survive their trip around the sun. Although they don't actually crash into the solar surface, the sun is able to destroy them anyway. Many sungrazing comets follow a similar orbit, called the Kreutz Path, and collectively belong to a population called the Kreutz Group. In fact, close to 85% of the sungrazers seen by the SOHO satellite are on this orbital highway. Scientists think one extremely large sungrazing comet broke up hundreds, or even thousands, of years ago, and the current comets on the Kreutz Path are the leftover fragments of it. As clumps of remnants make their way back around the sun, we experience a sharp increase in sungrazing comets, which appears to be going on now. Comet Lovejoy, which reached perihelion on December 15, 2011 is the best known recent Kreutz-group sungrazer. And so far, it is the only one that NASA's solar-observing fleet has seen survive its trip around the sun. Comet ISON, an upcoming sungrazer with a perihelion of 730,000 miles on November 28, 2013, is not on the Kreutz Path. In fact, ISON's orbit suggests that it may gain enough momentum to escape the solar system entirely, and never return. Before it does so, it will pass within about 40 million miles from Earth on December 26th. Assuming it survives its trip around the sun. ||

A new NASA spacecraft called the Solar Dynamics Observatory (SDO) will deliver startling images of the sun with ten times more detail than HDTV. The goal of the mission is to help scientists zoom in on solar activity such as sunspots, solar flares and coronal mass ejections, thus improving forcasts of solar storms. The complete script is available. For more information on the Solar Dynamics Observatory, check out their web site at http://sdo.gsfc.nasa.gov. ||