Sunspots

Close-up of Active Region 12593 through the 400 nm filter of the Swedish Solar Telescope. SDO/HMI provides the background image. || This imagery from the Swedish 1-meter Solar Telescope (SST) at La Palma, Spain is part of a series of multi-wavelength observations of a solar active region. This imagery is taken at a wavelength of light near the K-line of ionized calcium (Wikipedia). The goal of the observations was to better understand the methods by which non-thermal energy is injected into the solar chromosphere by mechanisms such as emerging magnetic fields in sunspots.In this close-up of the solar photosphere, we see the dark regions of sunspots, and solar granules changing with time. These granules are the tops of convection cells where hot gas rises from the interior to cool and then descend back down. The SST achieves its high resolution using an adaptive optics system to reduce the effects of atmospheric turbulence. Some frames of the movie exhibit blurring as the turbulence became too high to completely cancel out.To get a sense of scale of the closeup, the image covers a region 46,900 x 33,500 km. Since the diameter of Earth is about 12,700 km, it could fit four Earths in the horizontal dimension and three Earths in the vertical dimension. ||

A new sunspot collided with an existing sunspot which built up a highly sheared magnetic configuration. This resulted in a solar flare on December 13, 2006. || This movie opens with a full solar disk view from SOHO/MDI and zooms into the high-spatial and temporal resolution view from the Hinode SOT G-band filter. || A full disk view of the Sun from SOHO/MDI. || A close-up view of the sunspot of December 13, 2006 as seen by SOHO/MDI. Solar granulation is visible around the spots. || Now we see the same sunspots through the high-resolution optical camera on Hinode. ||

This zoom-in from a full view of the Hinode Solar Optical Telescope (SOT) (the same as in animation 3411) shows details of solar granulation and how rapidly it changes. || This movie starts with a full view of the Hinode SOT field and zooms in to show details of the solar granulation and how it changes with time. || The full Hinode SOT field-of-view. || Close-up view of the solar granulation. || Another view of the granulation where significant change is visible over the four hours of the data collection. ||

Zoom-in to the sunspot group and watch it rotate || Full sun view with SOHO-MDI data || Close-up on the sunspot group || Merging of the small spot with the larger spot || Final view of the merged and rotated sunspot || Slate title from video tape reads, 'SOHO and TRACE View a Spinning Sunspot.' || For More Information || See [http://www.gsfc.nasa.gov/topstory/20011210insidesun.html](http://www.gsfc.nasa.gov/topstory/20011210insidesun.html) ||

Three views of the Sun showing different levels of solar activity. The color table has been altered to enhance the appearance of the faculae (white regions) which are hotter than sunspots (red-black regions) and whose greater total area contribute to increasing the solar flux reaching the Earth. || Low solar activity - October 28, 1998 || Moderate solar activity - April 27, 2002 || High solar activity - March 28, 2001 ||

Scientists working with the SOHO/MDI instrument have continued to improve on previous results. Since the first release (SOHO/MDI's 'Window' Through the Sun), improvements in helioseismology techniques have enabled them to extract more information from the same data. In this case, sonogram-type imaging of the solar far side (the side of the Sun NOT facing the Earth) has been improved to provide a more complete view of the farside. This is important in space weather forecasting as it enables us to see large sunspots and active regions before they are visible directly from the Earth. Active regions are a source of solar flares which can send high-energy protons towards the Earth. These protons can damage satellite electronics, endangering communications and weather forecasting, and are a health threat to astronauts. ||

The Solar Dynamics Observatory, or SDO, has now captured nearly seven years worth of ultra-high resolution solar footage. This time lapse shows that full run from two of SDO's instruments. The large orange sun is visible light captured by the Helioseismic and Magnetic Imager, or HMI. The smaller golden sun is extreme ultraviolet light from the Atmospheric Imaging Assembly, or AIA, and reveals some of the sun's atmosphere, the corona. Both appear at one frame every 12 hours. SDO's nearly unbroken run is now long enough to watch the rise and fall of the current solar cycle. The graph of solar activity shows the sunspot number, a measurement based on the number of individual spots and the number of sunspot groups. In this case, the line represents a smoothed 26-day average to more clearly show the overall trend.Music: "Web of Intrigue" from Killer TracksWatch this video on the NASA Goddard YouTube channel.Complete transcript available. ||

The number of sunspots increases and decreases over time in a regular, approximately 11-year cycle, called the sunspot cycle. The exact length of the cycle can vary. It has been as short as eight years and as long as fourteen, but the number of sunspots always increases over time, and then returns to low again. More sunspots mean increased solar activity, when great blooms of radiation known as solar flares or bursts of solar material known as coronal mass ejections (CMEs) shoot off the sun's surface. The highest number of sun spots in any given cycle is designated "solar maximum," while the lowest number is designated "solar minimum." Each cycle, varies dramatically in intensity, with some solar maxima being so low as to be almost indistinguishable from the preceding minimum. Sunspots are a magnetic phenomenon and the entire sun is magnetized with a north and a south magnetic pole just like a bar magnet. The comparison to a simple bar magnet ends there, however, as the sun's interior is constantly on the move. By tracking sound waves that course through the center of the sun, an area of research known as helioseismology, scientists can gain an understanding of what's deep inside the sun. They have found that the magnetic material inside the sun is constantly stretching, twisting, and crossing as it bubbles up to the surface. The exact pattern of movements is not conclusively mapped out, but over time they eventually lead to the poles reversing completely. The sunspot cycle happens because of this poles flip — north becomes south and south becomes north—approximately every 11 years. Some 11 years later, the poles reverse again back to where they started, making the full solar cycle actually a 22-year phenomenon. The sun behaves similarly over the course of each 11-year cycle no matter which pole is on top, however, so this shorter cycle tends to receive more attention. ||

This animation shows sunpot migration over a 11 year solar cycle and indicates the features causing total solar irradiance variability. For a standard definition version of this animation, please go to animation 10151. || Solar cycle ||

This is a short movie of the Sun at the minimum of solar activity. This images are collected in ultraviolet light (a wavelength of 195 Å or 19.5 nanometers) which is only visible to space-based instruments. In visible light, few to now sunspots would be visible.At solar minimum, we see few bright active regions. The mottled look is from small 'hot spots' which last less than 48 hours. There are dark regions at the top and bottom of the Sun (corresponding to the north and south solar poles) created by solar magnetic field lines that connect to the interstellar magnetic field. A similar dark region, below the solar equator, is called a coronal hole, where open magnetic field lines enable particles to stream away at high speeds. ||

A short movie of the Sun at maximum solar activity as seen in ultraviolet light. These images are collected in ultraviolet light (a wavelength of 195Å or 19.5 nanometers) which is only visible to space-based instruments. In visible light, the bright white regions in these images would probably correspond to sunspots.At solar maximum, we see many bright active regions which tend to form in bands in the northern and southern hemispheres. Many of the active regions may eventually launch solar flares or coronal mass ejections (CME). ||

This is a sequence of solar synoptic maps covering Solar Cycle 23.The SOHO spacecraft began collecting this data in May of 1996, near the beginning (minimum) of the sunspot cycle. The sequence is projected in cylindrical-equidistant (CED) coordinates suitable for reprojection on spheres for animation or visualization purposes. These images are not suitable for scientific analysis.The original data were collected in FITS format from the SOHO/MDI archive, one image for each Carrington Rotation, which are 27.2753 days long.Solar minimum for Cycle 23 was in May 1996 (Carrington Rotation #1909), solar maximum around March 2000 (Carrington Rotation #1960), with a return to minimum about October 2008 (Carrington Rotation #2075). There are two gaps in the sequence, totalling four rotations, at Carrington rotations #1938, 1939, 1940, 1941, and 1998. These images are missing from the sequence due to SOHO being offline. Gaps in the data coverage for individual maps (occasional day outages or poor coverage near the poles of the Sun) were filled using data accumulated from previous maps.IMPORTANT NOTE: These images are for visualization purposes only. They are not suitable for scientific analysis. ||

This movie compares the spatial and temporal resolutions of the SDO/AIA (Atmospheric Imaging Assembly) imager to the SOHO/EIT (Extreme ultraviolet Imaging Telescope) imager. SOHO/EIT's highest resolution is 1024x1024 pixels with images taken about every 12 minutes for the 195 Ångstrom band. The SDO/AIA 193 band takes images at 4096x4096 pixels every twelve seconds!In this movie we can see the difference this makes for a closeup view of Active Region 1087. EIT reveals changes in the active region, which AIA reveals many details.This visualization is a companion piece to A Comparative View of the Sun: SDO/AIA 193 and STEREO-B/EUVI 195. ||

This animation shows sunpot migration over a 11 year solar cycle and indicates the features causing total solar irradiance variability. For a standard definition version of this animation, please go to animation 10151. || Solar cycle ||

During the course of the approximately 11 year sunspot cycle, the magnetic field of the Sun reverses. The last time this happened was around the year 2000. Using magnetograms from the SOHO/MDI and SDO/HMI instruments, it is possible to examine possible configurations of the magnetic field above the photosphere. These magnetic configurations are important in understanding potential conditions of severe space weather.The magnetic field in this animation is constructed using the Potential Field Source Surface (PFSS) model. The PFSS model is one of the simplest yet realistic models we can explore. Using the solar magnetograms as the 'source surface' of the field, it builds the field structure from the photosphere out to about two solar radii (an altitude of 1 solar radius). These visuals were generated using the SolarSoft package. In this visualization, the white magnetic field lines are considered 'closed'. The move up, and then return to the solar surface. The green and violet lines represenent field lines that are considered 'open'. Green represents positive magnetic polarity, and violet represents negative polarity. These field lines do not connect back to the Sun but with more distant magnetic fields in space. These field lines act as easy 'roads' for the high-speed solar wind. ||

SOHO/MDI performs a 'sonogram' of the sun, revealing the subsurface temperature profile around a sunspot. Red isosurfaces denote regions where the sound speed (and temperature) are higher than average while blue isosurfaces directly under the spot illustrate where the sound speed (and temperature) are lower than average. || Zoom down to and below the solar surface to see temperature isosurfaces below the sunspot. || A full view of the sun at the start of the fly-in. || A close-up view of the sunspot in the region of interest. ||

When a large bundle of magnetic field lines breaks through the Sun's surface, a sunspot can form. Sometimes, a smaller spot will emerge nearby, creating a magnetically complex region where particles are energized and then violently expelled. Supercomputer models show that rearranging magnetic field lines enables this process. || A animation of the magnetic field of a sunspot, where the magnetic field at the Suns surface is colored blue for strong fields pointing into the sun and red for strong fields pointing out of the Sun. The white lines represent magnetic field lines. ||