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  • Swedish Solar Telescope: Solar Closeups
    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.
  • Hinode Sunspot Image
    Hinode's Solar Optical Telescope (SOT) provides crystal-clear images of various features on the sun's surface. This video shows the whirl of a newly developing sunspot colliding with an existing spot, which explodes into a major solar flare. The solar flare shown in this movie was captured on December 13, 2006. The flare produced high-energy protons that reached the Earth during the Space Shuttle flight STS-116. The flare is shown in 3 different wavelengths.
  • Hinode's High-resolution view of solar granulation
    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.
  • The Spinning Sunspot
    Zoom-in to the sunspot group and watch it rotate
  • The Solar 'Constant' - Faculae vs. Sunspots
    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.
  • The Visible Sun
    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 Cycle

  • SDO: Year 7
    Our sun is ever-changing, and the Solar Dynamics Observatory has a front-row seat. On Feb. 11, 2010, NASA launched the Solar Dynamics Observatory, also known as SDO. SDO keeps a constant eye on the sun, helping us track everything from sunspots to solar flares to other types of space weather that can have an impact on Earth. For instance, solar activity is behind the aurora, one of Earth’s most dazzling natural events. The sun’s activity rises and falls in a pattern that lasts about 11 years on average. This is called the solar cycle. After seven years in space, SDO has had a chance to do what few other satellites have been able to do – watch the sun for the majority of a solar cycle in 11 types of light. This video shows two.
  • The Solar Cycle
    The number of sunspots increases and decreases over time in a regular, approximately 11-year cycle, called the sunspot cycle.
  • Solar Cycle (High Definition)
    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.
  • Comparison: Solar Minimum from SOHO/EIT
    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.

  • Comparison: Solar Maximum from SOHO/EIT
    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).

  • Solar Cycle 23: Minimum-Maximum-Minimum Synoptic Sequence

    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.

  • A Comparative View of the Sun: SDO/AIA 193 and SOHO/EIT 195
    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.

  • Solar Cycle
    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.
  • The Sun's Magnetic Field
    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.

Sunspot Science

  • SOHO/MDI Investigates Solar Flows Under Sunspots
    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.
  • Delta Sunspot
    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.