Mt. Wilson sunspot numbers and butterfly diagram
November 23, 2003 Solar Eclipse Press Release
Galileo's sunspot drawings animated
SEDS (Students for the Exploration and Development of Space) Homepage
SOHO (Main homepage from NASA)
Current Realtime
Images of the Sun from SOHO
Yohkoh Public Outreach Project Includes photos and movies
TRACE Homepage
Stanford SOLAR Center
SoHO Gallery
Rome, Italy, Solar Images
Sunspot Numbers On-Line
Sunspot count
on-line
GONG On-Line
New Solar Web Sites
The
Solar Constant
Coronal data collected during the 1970's by the Skylab coronagraph
Mauna Loa
Solar Observatory (Hawaii) Data Analysis Home Page
Solar
Maximum Mission Coronagraph [1980, 1984-1989] CME Events Home Page
Exploratorium:
Eclipses and Sunspots
Summaries of both HESSI and
SOLIS, solar spacecraft
Ramaty HESSI satellite
Daily Big Bear Solar
Observatory images
Solar Max Web Site: Lots of information
about the Sun, with links to photos from the ground and from space
The Solar Section
of the Association of Lunar & Planetary observers (ALPOSS)
A current Sacramento
Peak H-alpha solar image
San Fernando Observatory Web
Site
The Sun: A Multimedia Tour
Butterfly diagram
Sunspot Index Data Center
Mauna Loa Mark IV Coronagraph
Comparison of Mark III and Mark
IV
NASA Sun-Earth Connection program
NASA Living With a Star
High-Energy Solar Spectral Imager (HESSI)
Imager for Magnetopause-to-Aurora Global Exploration (IMAGE)
Thermosphere-Ionosphere-Mesosophere-Energetics and Dynamics (TIMED)
Solar-B
Solar Probe
Solar TErrestrial RElations Observatory (STEREO)
NOAA Space Environment Center
Sun-Earth Connection Educational Forum events
list
Sun-Earth Connection Forum (East Coast)
Sun-Earth Connection Forum (West Coast)
Saros and Metonic Cycles
Stanford Solar Center, links
Stanford Solar Center
Following are links to images of the sun in various wavelengths. All were taken on August 11, 1999, when a total solar eclipse occurred.
White
light
H-Alpha
Calcium
K-Line
Magnetogram
Coronagram,
2-6R
Coronagram,
4-30R
EUV
X-Ray
Incorrect
SOHO stands for Solar Helioseismology....
Correct
SOHO stands for Solar and Heliospheric, where the heliosphere is the sphere
around the sun (Helios).
Incorrect
The Sun has a radioactivity zone.
Correct
The Sun has, inside its convection zone, a radiation zone, that is, a zone in
which energy is transported by radiation instead of by convection. Radioactivity,
the decay of nuclear particles, is not a phenomenon that takes place in or on
the Sun.
Incorrect
Scientists study helioseismology by studying wavelengths.
Correct
Scientists study helioseismology by studying waves on the surface of the Sun.
The periods with which these waves oscillate are different for waves that penetrate
the Sun to different distances.
Incorrect
To use helioseismology, scientists send waves into the Sun.
Correct
To use helioseismology, scientists observe waves that are naturally generated
by the Sun.
Incorrect
The chromosphere, seen every day by looking straight at the Sun, has emission
lines because it is hotter than the photosphere.
Correct
The chromosphere is too transparent to add emission lines to the solar absorption
lines. Only when we see it at the edge of the Sun (known as the "limb") do we
detect emission lines, because then we see the chromosphere in silhouette against
dark sky. We can see the chromosphere and prominences in this way every day
with telescopes on Earth that use H-alpha filters or without filters at the
times of total solar eclipses.
Sunspot, NM (Dec. 18, 2003) -- As last October's solar flares blossomed into a coronal mass ejections, scientists at the National Solar Observatory used a new set of instruments to record the sharpest-ever images of the heart of the storms.
"A stunning H-alpha flare movie was made and shows, to our knowledge for the first time, flare structure at scales of 0.2 arc-seconds," said Dr. Thomas Rimmele, project scientist for the NSO's Adaptive Optics (AO) project. In addition, the new Diffraction Limited Spectropolarimeter (DLSP) captured high-resolution polarization maps that are essential to studying the fine structure of magnetic activity on the Sun.
The DLSP, a joint project of the NSO and the High Altitude Observatory in Boulder, CO, is the first instrument designed to take advantage of the AO76 system. The story and high-resolution images are on line atScientists using the Solar and Heliospheric Observatory (SOHO) spacecraft have been able to monitor the activity of the recent powerful solar magnetic active regions that were hidden on the far side of the Sun as they rotated with the Sun to face the Earth again.
Principal Investigator Dr. Jean-Loup Bertaux and colleague Dr. Eric Quemerais of the Service d'Aeronomie in the Paris suburb of Verrieres le Buisson have found that the activity of the sunspot regions numbered 10486 and 10484 by the National Oceanic and Atmospheric Administration Space Environment Center (NOAA SEC) has decreased dramatically in recent days. However, even more recently (18 and 19 November), the activity of these active regions has increased again.
These giant active regions were on the side of the Sun facing the Earth during the period October 26 - November 4, when a series of intense flares and coronal mass ejections produced dramatic space weather effects. (There were eight X-class flares, the most intense classification of soft X-ray events measured by NOAA's GOES spacecraft, from the two giant regions.) On October 28, the shock wave driven by a very fast coronal mass ejection (CME) associated with an X28 flare accelerated electrically charged particles that affected spacecraft throughout the solar system.
The Sun rotates once every roughly 27 days at its equator: would these active regions appear again this week and create more problems for satellite operators? Until recently, the problem of knowing what was happening on the far side of the Sun appeared intractable. In 2000, however, researchers using both the Michelson Doppler Imager (MDI) and Solar Wind ANisotropies (SWAN) instruments on SOHO began producing data on farside activity. MDI uses a holographic reconstruction technique to map the presence of sunspot groups that modify the transmission of acoustic waves beneath the solar surface; SWAN is able to determine how "active" the regions are in the ultraviolet portion of the spectrum.
"Any hope of improving longer term forecasts of space weather requires an ability to monitor active regions as they transit the far side of the Sun," said Dr. Joseph Kunches of NOAA SEC. "SOHO instruments MDI, SWAN, and LASCO have demonstrated the ability to track active regions across the invisible disk in new ways, benefiting forecasters and users of space weather information."
"When we first proposed the SWAN instrument for SOHO in 1989,we wanted to study the science of the interaction of the solar wind with interstellar gas. Now, we are delighted to see that it could actually be useful outside the field of pure science, by improving the prediction of solar activity, which may impact many sectors of technology like spacecraft operations", said Bertaux.
SWAN can indirectly monitor the activity on the far side of the Sun as it maps the whole sky in ultraviolet light. A huge cloud of interstellar hydrogen that bathes the entire Solar System interacts with the solar wind, and lights up in the Lyman-alpha spectral line when it is hit by UV radiation from the Sun. Since active regions on the Sun are brighter in Lyman-alpha light, the part of the sky facing an active region is brighter. Just as a rotating lighthouse beam will illuminate different patches of fog, the Sun's rotation produces a changing pattern of Lyman-alpha illumination on the sky behind the Sun's far side. Any change in the solar activity is in this way directly reflected in the amount of Lyman-alpha emission that is observed by SWAN.
After October 28, the SWAN team started observing farside activity more intensively. They found that the Lyman-alpha sky brightness could be correlated with the "Mg II index," a measure of the integrated brightness of a strong spectral line of ionized magnesium in the Sun's outer atmosphere. The Mg II index is measured from earth-orbiting spacecraft such as the UARS and SORCE missions of NASA's Earth Science enterprise, and is a good measure of total solar activity.
The SWAN team used their data to estimate what the MgII index would be for an observer rotating with the Sun, and always facing a given active region during the solar rotation. The MgII index estimated from SWAN data increased up to November 7, but then began rapidly decreasing. The corresponding decrease of the solar Lyman-alpha brightness found by SWAN was 20%, an indication that the activity of the two active regions decreased significantly since their stunning performance on the near side of the Sun. This method should prove of value to space weather forecasters, who are just as interested in predicting "clear" days as they are in forecasting storms from the Sun. For images, refer to:
Related Web sites:
http://nicmosis.as.arizona.edu:8000/ECLIPSE_WEB/ECLIPSE_03/ECLIPSE_03.html
http://www.eclipses.info
No one has ever seen a total solar eclipse from over the Antarctic. But next Sunday, passengers on two separate chartered aircraft will get first-ever views of a total solar eclipse from high over a small slice of the South Polar continent.
University of Arizona astronomer Glenn Schneider helped plan the two aircraft intercepts of the Nov. 23 total solar eclipse, which won't be visible from land anywhere else on Earth.
Schneider will be in the navigator's seat on one of the aircraft, a chartered Qantas Boeing 747-400. It will carry solar eclipse chasers, scientists, photographers, amateur astronomers and tourists on a 14-hour, nonstop roundtrip flight out of Melbourne, Australia. Schneider has worked with Qantas pilots for the past several years in planning the special flight, arranged through Croydon Travel of Melbourne. He will assist the flight crew in navigating the plane through the moon's shadow during "totality," when the moon entirely blocks the sun.
Passengers in the moving aircraft might see totality for as long as 2 minutes, 36 seconds, if there is little or no wind, compared to less than 2 minutes that totality will last at ground sites. The eclipse occurs at 22:40 Universal Time (5:40 p.m. Eastern time), which is 9:40 a.m. Monday, Nov. 24, Melbourne time.
Schneider developed computer software called "EFLIGHT," a navigational program specifically for flying aircraft into the path of total eclipses. It helps pilots respond to real-time, in-flight conditions to get the best possible "totality run." He used EFLIGHT in planning two previous airborne missions that intercepted the total solar eclipses of Oct. 3, 1986, and June 30, 1992. He also planned to use EFLIGHT on the Concorde for a 2001 eclipse. But that flight was canceled after Air France grounded its Concorde fleet following a crash.
For the Nov. 23 eclipse, pilots on two aircraft will use EFLIGHT in their flight management systems. Schneider and the Qantas pilots conducted a dry-run test on the system last July in a 747 flight simulator. Meanwhile, Sky and Telescope magazine and Travelquest International chartered a Lan Chile Airbus A340 for the eclipse. That plane will fly out of Punta Arenas, Chile. Sky and Telescope recruited Schneider to assist planning its flight, too.
On the Qantas eclipse flight, Schneider will operate four cameras on a gyro-stabilized platform suspended over the flight deck by bungee cords. The cameras will be controlled by computer software that Schneider wrote, and a Sony video camera will guide the platform by feeding images to the computer system. Three still photo cameras will be used to photograph the eclipse: a Pentax ZX-5n equipped with a 500 mm f/5.6 lens, a Nikon F5 equipped with Nikon Vibration-Reduction 80-400 mm zoom, and a Santa Barbara Instrument Group 1024 x 1024 CCD digital camera with a 300 mm lens and special green filter. The filter is used to create better images of the sun's inner corona.=20
The camera equipment was provided by collaborators including Jay M. Pasachoff of Williams College. Pasachoff, who chairs the International Astronomical Union's Working Group on Eclipses, will be on the Qantas flight.
Schneider occasionally may have to blow on the camera platform if it begins to drift away from the 16-by-27-inch window that the cameras peer through. A breath of air is all that's needed -- touching the platform would send it swinging.
The B747-400 will fly at about 470 nautical mph at 38,000 feet. It will fly within a kilometer of the center of the moon's shadow, within 100 meters of its target vertical position, and within a 6-second time margin.
The moon's shadow, which is about 64 nautical miles across, moves at 2,200 nautical mph, or about 4-and-one-half times faster than the airplane. It will overtake the plane from behind.
"The moon's shadow will be projected down below us onto the cloud tops, so the snow and ice will be dark," Schneider said. "There will be no reflected sunlight coming back up. The sky will be black."
Scientists plan to make some unique light-scattering measurements on Earth's upper atmosphere during the flight, Schneider said. They will use the moon's shadow as an illumination probe to get information on particle distribution that they can=B9t get with remote sensing or LIDAR.
Schneider is an associate astronomer at the UA Steward Observatory. He also is the project instrument scientist for the NICMOS, the instrument that gives the Hubble Space Telescope its infrared vision.
Schneider describes himself as an "umbraphile," literally a "shadow lover," one who is "addicted to the glory and majesty of total solar eclipses." Umbraphillia "is not only an addiction, but an affliction, and a way of life, the real raison d'etre for many of us," Schneider said. Umbraphiles are commonly called "solar elipse chasers," people who once every 16 months or so "will drop whatever they are doing and trek by plane, ship, train, foot, and camel-back to gather along a narrow strip in some remote God-forsaken corner of the globe."
Because Schneider is willing to travel, he has seen 23 eclipses since 1970 and been clouded out only three times.
But travel often entails killer jet lag. The 14-hour eclipse flight returns to Melbourne at 3 p.m. local time. Schneider then will repack the cameras, gryo platform, computers, inverters, power supplies, etc. into shipping crates to catch an 8 a.m. flight the following morning -- the start of his 28-hour trip back to Tucson.
"I missed Thanksgiving last year because I was in the Australian outback for the last eclipse, and I promised my wife I'd be home for Thanksgiving this year," he said.
Macintosh users can download Schneider's software for photographing a solar eclipse, called "Umbraphile," from the Internet for free. Given the particulars of an eclipse, the program computes an exposure sequence table synced to Universal Time and automatically fires the camera at correct exposures. The software is online at:Seehttp://www.esa.int/export/esaSC/SEMNFTWLDMD_index_0.html for information about the solar flare.
See http://www.spaceweather.com for daily images and a gallery of photographs of auroras.
"This is the real thing," says John Kohl, a solar astrophysicist at the Harvard-Smithsonian Center for Astrophysics (CfA) and principal investigator for the Ultraviolet Coronagraph Spectrometer on board NASA's Solar and Heliospheric Observatory (SOHO) spacecraft. "The eruption was positioned perfectly. It's headed straight for us like a freight train, so a major geomagnetic storm is bound to happen when it reaches us on October 29th or 30th."
"Last week's CME hit the Earth with only a glancing blow," says Kohl, although it was sufficient to disrupt airline communications. "Today's eruption was pointed directly at us, and is expected to have major effects."
"This is the strongest flare we've seen in the past 30 years," says Leon Golub, CfA astrophysicist and author of "Nearest Star: The Surprising Science Of Our Sun." Today's solar flare was classified as an X18-category explosion, meaning that it can trigger planet-wide radio blackouts and long-lasting radiation storms.
"We are waiting for the prediction of the geomagnetic storm level from NOAA (the National Oceanic and Atmospheric Administration)," says Kohl. "What we know at this point is that the flare was nearly perfectly positioned near the center of the Sun, and that a halo coronal mass ejection has left the Sun and is heading toward the Earth. The geomagnetic storm is likely to be a strong one, and will last about 24 hours."
NOAA classifies geomagnetic storms on a scale from 1 to 5. Initial indications show that this has the potential to be a G5 storm - the top of the scale. The most benign effect of such a storm would be bright auroras visible from more southern latitudes than usual. However, the geomagnetic storm triggered by the CME also could interfere with satellite communications; disrupt power grids (as occurred in the 1989 Quebec blackout); even short out orbiting satellites, rendering them permanently inoperable.
"We've already had to shut down our SOHO instrument for safety reasons. It's getting blasted by high-energy particles from this solar flare," says Kohl. "Of more concern, geosynchronous communications satellites are likely to be affected." In California, where raging wildfires have damaged many microwave communication antennas on the ground, satellite communications have been crucial to emergency efforts. Emergency personnel should be prepared for potential disruptions and communication interference.
"There's no direct danger to people on the ground," Kohl adds, "and I'm sure that NASA is monitoring the situation for any potential effects on the space station crew, and that they are taking appropriate precautions."
According to NOAA, a G5-class geomagnetic storm can have the following effects:
Power systems: Widespread voltage control problems and protective system problems can occur, some grid systems may experience complete collapse or blackouts. Transformers may experience damage.
Spacecraft operations: May experience extensive surface charging, problems with orientation, uplink/downlink and tracking satellites.
Other systems: Pipeline currents can reach hundreds of amps, HF (high frequency) radio propagation may be impossible in many areas for one to two days, satellite navigation may be degraded for days, low-frequency radio navigation can be out for hours, and aurora has been seen as low as Florida and southern Texas (typically 40 degrees geomagnetic lat.).
Solar astronomers say to stay tuned. This eruption is coming our way!
JHUAPL Press Release, May 28, 2002
The online version of this release is available on the APL Web site:
NASA's TIMED (Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics)
spacecraft recently observed our atmosphere's response to a series of strong
solar storms, providing important new information on the final link in the
Sun-Earth Connection (SEC) chain of physical processes connecting the Sun
and Earth.
"Several NASA spacecraft measured this strong activity coming from the Sun.
Now TIMED provides the critical link between what happened on the Sun and
Earth's response," says Dr. Sam Yee, TIMED project scientist, from the
spacecraft's operations center at the Johns Hopkins University Applied
Physics Laboratory in Laurel, Md., and leader of the mission's science team.
"TIMED allows us to observe the global reaction of our upper atmosphere to
solar activity," says Dr. Mary Mellott, TIMED program scientist from NASA
Headquarters in Washington. "One of the current puzzles for the Sun-Earth
Connection community is determining why some solar activity has significant
geospace impact and some does not. Being able to monitor the impact so well
with TIMED should allow the scientific community to make significant
progress toward solving this SEC mystery."
Preliminary TIMED data will be featured in a special session at the Spring
2002 American Geophysical Union meeting, May 31, in Washington, D.C., which
is open to the media. Information about this session can be found at
www.agu.org/meetings/sm02Sessions.html#SA (item SA02).
Interested members of the press should
visit
www.agu.org/sci_soc/media.html for registration information.
Since TIMED's science mission began in January 2002, science team members
say it has made great strides in helping them learn more about one of
Earth's least understood atmospheric regions-the Mesosphere and Lower
Thermosphere/Ionosphere-a gateway between Earth's environment and space.
TIMED is the first of NASA's Solar Terrestrial Probes missions to globally
study the influences of the Sun and humans on the MLTI region, located
approximately 40-110 miles (60-180 kilometers) above the surface.
"TIMED's study of short-term events, such as the recent solar storms, will
help us gain a better understanding of the dynamics of this gateway region,"
says Dr. Yee. "But our main goal is to understand the region's overall
climate through a comprehensive set of global measurements we're collecting
using TIMED's 4-instrument suite. With the core data we've already
collected, we've taken the first step in assessing the region's global
characteristics and seasonal variations-information that will help us
establish a baseline for future studies."
Space weather in Earth's upper atmospheric regions can change as suddenly as
our weather patterns on the ground. It can affect satellite communications
and orbital tracking, spacecraft lifetimes and the reentry of piloted
vehicles. "When a change occurs in one region of our atmosphere, it affects
other regions," Dr. Yee says. "It's important that we better understand how
this gateway region responds to various solar inputs, which affect our
atmosphere's overall energy balance."
Images and videos of preliminary TIMED data can be downloaded from
The Solar Terrestrial Probes Program Office at NASA's Goddard Space Flight
Center, Greenbelt, Md., oversees the TIMED mission for the Office of Space
Science at NASA Headquarters in Washington, D.C. The Johns Hopkins
University Applied Physics Laboratory, in Laurel, Md., built and now
operates the spacecraft, leads the project's science effort and manages the
mission's Science Data Center for NASA.
ESA Press Release, May 21, 2002
For centuries, we have worshipped it and wondered at it, but it's
only now that we are getting a really good look at it. Although
you can't gaze at the Sun with the naked eye, thanks to modern
science, in particular ESA's solar fleet, we can view images of our
nearest star that confirm the fiery glory our ancestors could only
imagine.
Remarkable imagery from ESA's SOHO spacecraft is the inspiration
behind Sunsation - an exhibition that seeks to bring our vision of
the Sun up to date by combining the most stunning solar images from
space with other images from our everyday world.
Read more about this at:
and visit the Sunsation exhibition at:
Just in time for Sun-Earth Day, a new NASA spacecraft,
complete with a new name, made its debut by observing a huge
explosion in the atmosphere of the Sun. The blast, called a
solar flare, was equal to one million megatons of TNT and
gave off powerful bursts of X-rays.
The solar fireworks were captured by what is now known as the
Reuven Ramaty High-Energy Solar Spectroscopic Imager
spacecraft, or RHESSI. The spacecraft launched last month as
HESSI was recently renamed in honor of Dr. Reuven Ramaty, who
died in 2001 after a long and distinguished career in the
Laboratory for High Energy Astrophysics at the NASA Goddard
Space Flight Center, Greenbelt, Md. Ramaty was a pioneer in
the field of solar-flare physics, gamma-ray astronomy and
cosmic rays.
"We are thrilled to be making the first high-resolution
movies of flares using their high-energy radiation," said
Brian Dennis, the RHESSI mission scientist at Goddard. "We
want to understand how solar flares can explosively release
so much energy. RHESSI shows us the high-energy radiation
emitted by flares: their X-rays and gamma rays. This
radiation reveals the core of the flare -- the exact time and
place where the energy is released."
Scientists believe solar flares are powered by the violent
release of magnetic energy, but how this happens is unknown.
A new movie features one of the first flares recorded by
RHESSI, which occurred Feb. 20 in the southern hemisphere of
the Sun, an active region designated "AR 9830."
It was a moderately powerful flare, classified as M2.4 by the
National Oceanic and Atmospheric Administration (NOAA). The
most powerful flares, designated X-class by NOAA, can release
up to 1,000 times more energy.
During its planned two-year mission, RHESSI will study the
secrets of how solar flares are produced in the Sun's
atmosphere. Launched Feb. 5, RHESSI is now fully operational
after only six weeks in orbit. It is observing the Sun and
recording the high-energy radiation from solar flares as they
occur.
RHESSI is the first NASA Small Explorer mission being managed
in the "Principal Investigator" mode. The Principal
Investigator, Robert Lin of the University of California,
Berkeley, is responsible for most aspects of the mission,
including the science instrument, spacecraft integration and
environmental testing, and spacecraft operations and data
analysis.
The RHESSI scientific payload is a collaborative effort among
the University of California, Berkeley; Goddard; the Paul
Scherrer Institut in Switzerland; and the Lawrence Berkeley
National Laboratory in Berkeley. The mission also involves
additional scientific participation from France, Japan, The
Netherlands, Scotland and Switzerland.
A movie of the flare recorded by the RHESSI spacecraft is
available on the Internet at:
RHESSI data are now available online to the general public
at:
NASA'S High Energy Solar Spectroscopic Imager, or HESSI, lifted off
on February 5, 2002, from Cape Canaveral Air Force Station, Fla. at 2:29
p.m. EST. During its planned two-year mission HESSI will study the
secrets of how solar flares are produced in the Sun's atmosphere.
Tucked inside a Pegasus XL rocket, attached to the under belly of the
Orbital Stargazer L-1011 aircraft, the spacecraft was carried
approximately 113 nautical miles east-southeast of the Cape to an
altitude of about 39,000 feet. The Pegasus drop occurred at 3:56 p.m.
EST, and after a short powered sequence, delivered the 645-pound
HESSI spacecraft into a circular orbit 373 miles above the Earth,
inclined at 38 degrees to the equator.
"We're extremely thrilled to report the Pegasus drop went without a
hitch," said Frank Snow, HESSI Project Manager at NASA's Goddard
Space Flight Center, Greenbelt, Md.
HESSI will help unlock some of the secrets of these gigantic
explosions in the Sun's atmosphere, providing scientists with the
first high-fidelity color movies of solar flares in X-rays and gamma
rays, which is their highest energy emissions. Scientists hope to
capture hundreds of X-ray and gamma ray flares during the
spacecraft's planned two-year mission.
Science operations should begin in about three weeks, after germanium
detectors inside the X-ray/gamma-ray imaging spectrometer are cooled
to their operating temperature of minus 320 degrees Fahrenheit,
turned on and checked out.
HESSI is the first NASA Small Explorer mission being managed in the
'principal investigator' mode. Professor Robert Lin of the
University of California, Berkeley, is responsible for many aspects
of the mission, including the science instrument, spacecraft
integration and environmental testing, and spacecraft operations and
data analysis.
The HESSI scientific payload is a collaborative effort between the
University of California, Berkeley, NASA's Goddard Space Flight
Center, the Paul Scherrer Institut in Switzerland, and the Lawrence
Berkeley National Laboratory in Berkeley. The mission also involves
scientific participation from France, Japan, The Netherlands,
Scotland, and Switzerland.
The Explorers Program Office at Goddard manages the HESSI mission for
NASA's Office of Space Science in Washington, D.C. Spectrum Astro,
Inc. of Gilbert, Ariz., constructed the HESSI spacecraft and provided
integration support.
The HESSI mission cost, including the spacecraft, science instrument,
launch vehicle, and mission operations and data analysis, is
approximately $85 million.
For additional details about the mission, go to:
http://hesperia.gsfc.nasa.gov/hessi
NASA Press Release, December 11
A new NASA spacecraft that will study the effects of the sun and
human-induced activities on the least explored and understood region
of Earth's atmosphere soared into a clear early morning California
sky on December 7, 2001.
The TIMED (Thermosphere Ionosphere Mesosphere Energetics and
Dynamics) spacecraft lifted off from the Western Range of Vandenberg
Air Force Base, Calif., aboard a Delta II rocket at 10:07 a.m. EST.
Spacecraft separation from the Delta II rocket's second stage motor
occurred at 12:13 p.m. EST, inserting TIMED into a 388-mile
(625-kilometer) circular orbit around the Earth.
At 1:10 p.m. EST, controllers at the TIMED Mission Operations Center
of The Johns Hopkins University Applied Physics Laboratory (APL) in
Laurel, Md., made contact with TIMED as it passed over a ground
station in Kiruna, Sweden, confirming that solar arrays deployed,
providing power to the spacecraft.
"Three hours is a long time to hold your breath," said TIMED Project
Manager Bruce Campbell at NASA's Goddard Space Flight Center in
Greenbelt, Md., "and we're pleased with the way things look right
now."
Solar array deployment occurred immediately following spacecraft
separation. During the next 30 days or so, controllers will turn the
four instruments on and check them out prior to starting science
observations. TIMED should be ready to begin its global study of the
MLTI region in mid-January 2002.
"TIMED will provide a very important benchmark for future studies of
both natural and human-induced changes to the Earth's atmosphere,
said Sam Yee, TIMED project scientist at APL. "TIMED's measurements
will help scientists understand how the region's composition is
affected by contaminants that are released into Earth's atmosphere
and by solar energy entering this region."
The TIMED mission is sponsored by NASA's Office of Space Science in
Washington, D.C., and managed by the Solar Terrestrial Probes Program
Office at Goddard. APL designed, built and will operate the TIMED
spacecraft and lead the science effort for NASA.
More information about the TIMED mission is available on the
following web sites:
NASA Press Release 01-216, November 7
Scientists now have the first clear picture of what lies beneath
sunspots, enigmatic planet-sized dark areas on the Sun's surface, and
have peered inside the Sun to see swirling flows of electrified gas
or plasma that create a self-reinforcing cycle, which holds a sunspot
together.
The new research, gathered from the Michelson Doppler Imager (MDI)
onboard the Solar and Heliospheric Observatory (SOHO) spacecraft,
will deepen understanding of the stormy areas on the Sun in which
sunspots appear. Vast explosions associated with these active
magnetic regions occasionally affect high-technology systems.
Sunspots have fascinated people since Galileo's observations of them
contradicted the common belief that heavenly objects were flawless.
Sunspots remain mysterious because at first glance, it seems they
should rapidly disappear. Instead, they persist for weeks or more.
"They obey what is a fundamental finding of observational science:
Anything that does happen, can happen," said Philip Scherrer of
Stanford University, Palo Alto, Calif., Principal Investigator for
SOHO's MDI. "We now have a hint at 'how.'"
Astronomers know sunspots are regions where magnetic fields become
concentrated. Yet, anyone who played with magnets as a child has felt
how magnetic fields of like polarities repel each other. The strong
solar magnetic fields should naturally repel each other also, causing
the sunspot to dissipate. In fact, observations show that surface
material clearly flows out of the spots.
Alexander Kosovichev and Junwei Zhao of Stanford University and
Thomas Duvall of NASA's Goddard Space Flight Center, Greenbelt, Md.,
used MDI's unique ability to look just below the sunspot's surface
and clearly observed inward-flowing material for the first time. The
Astrophysical Journal published their research August 10.
"We discovered that the outflowing material was just a surface
feature," said Zhao. "If you can look a bit deeper, you find material
rushing inward, like a planet-sized whirlpool or hurricane. This
inflow pulls the magnetic fields together."
Solar astronomers have long known that the intense magnetic field
below a sunspot strangles the normal up-flow of energy from the hot
solar interior, leaving the spot cooler and therefore darker than its
surroundings. The suppression of the bubbling convective motions
forms a kind of plug that prevents some of the energy in the interior
from reaching the surface.
The material above the plug cools and becomes denser, causing it to
plunge downward at up to 3,000 miles per hour, according to the new
observations. That draws the surrounding plasma and magnetic field
inward toward the sunspot's center. The concentrated field promotes
further cooling, and as that cooling plasma sinks it draws in still
more plasma, thereby setting up a self-perpetuating cycle. As long as
the magnetic field remains strong, the cooling effect will maintain
an inflow that makes the structure stable. The superficial outflows
seen right at the surface are confined to a very narrow layer.
Since the magnetic plug prevents heat from reaching the solar
surface, the regions beneath the plug should become hotter. A June
1998 observation provided evidence for this also. "We were surprised
at how shallow sunspots are," said Kosovichev. Below 3,000 miles the
observed sound speed was higher, suggesting that the roots of the
sunspots were hotter than their surroundings, just the opposite of
the conditions at the surface. "The cool part of a sunspot has the
shape of a stack of two or three nickels," he added.
"The cool downward flows dissipate at the same depth where the hot
upward flows diverge," said Duvall. "With these data one cannot get a
sharp enough picture to really explain the details. Until now we've
looked down at the top of sunspots like we might look down at the
leaves in treetops. For the first time we're able to observe the
branches and trunk of the tree that give it structure. The roots of
the tree are still a mystery."
MDI explores beneath the surface of the Sun by analyzing
sound-generated ripples at its surface using a technique called
acoustic tomography -- a novel method similar to ultrasound
diagnostics in medicine that use sound waves to image structures
inside the human body. SOHO continues to mark an era of successful
partnership between the European Space Agency and NASA within the
Solar Terrestrial Science program.
Images and more information are available at:
Note that you should not look at the Sun directly to see the
sunspots. The sun is too bright to look at directly without using a
filter that cuts out 99.999% of the light.
The latest values of the solar constant as measured by the VIRGO
experiment on SOHO, along with past measurements from several
spacecraft, are available on line at
A new solar imaging service.
Goal: To provide a highly contiguous and high-cadence permanent daily
24-hour hydrogen alpha movie of the Sun.
We are presently collaborating with the National Solar
Observatory/Sacramento Peak at Sunspot, New Mexico, and the
Kanzelhohe Solar
Observatory of the Institute of Geophysics, Astrophysics and
Meteorology at
the University of Graz, Austria. These two observatories alone are
capable
of providing up to approximately 21 hours of coverage per day when
cloudless. In order to help ensure the most contiguous coverage
possible
during cloudy periods, we need imagery from other locations as
well. Our
server automatically selects and uses the best cloud-free images.
The latest H-alpha image from this service is available at the
URL:
All movies are 512x512 pixels.
At the end of each day, all of the images received during the
day are
processed into a single larger MPEG movie and permanently archived at: We should be able to keep
about
six months to one year of data on-line. The rest will be kept off-line
and
will be available by request. This will be a permanently available,
public-domain resource to the science community.
The Japanese/US Solar B spacecraft to be launched in 2005 will carry a
set of visible-light, extreme ultraviolet, and x-ray telescopes.
The San Fernando Observatory has recently reorganized its Web site. In particular,
daily updated photometric full-disk solar images in two wavelengths are available.
In the near future, we plan daily postings of sunspot number, area, and location,
and facular areas. A downloadable archive of SFO's twelve years' worth of photometric
full-disk solar images is being developed, and should be partially in place
by the end of 1998.
The site is located at http://davinci.csun.edu/~astro/sfo.html.
Eight radial-filter eclipse images from the National Center for Atmospheric
Research and a variety of coronal images from the Solar Maximum Mission are
viewable on the
Web and can be ordered as slides.
We are pleased to announce the launching of the first installment of a
prototype education/public outreach product, "Thursday's Classroom,"
produced by the NASA/Marshall Science Directorate.
The first installment deals with solar eclipses, and future episodes
of this
prototype will introduce other solar science topics, specifically,
sunspots,
the sun-earth connection, solar observing, and the solar cycle.
Our aim is to provide a lasting connection between NASA's latest
research
and the classroom environment. We welcome your feedback and invite you
to
explore our product at
http://thursdaysclassroom.com
Sincerely,
For space weather updated regularly, including images of the sun, see http://www.sec.noaa.gov/sec_home.html
and www.spaceweather.com.
www.timed.jhuapl.edu/press2/images.htm.
Sunsation from the European Space Agency
http://sci.esa.int/content/news/index.cfm?aid=1&cid=1&oid=29995
http://sunsation.esa.int/
Ramaty HESSI satellite studies solar flares
NASA Press Release, 3/20/02
http://www.gsfc.nasa.gov/topstory/20020320hessixray.html
http://hesperia.gsfc.nasa.gov/hessi/
HESSI Solar Spacecraft Reaches Orbit
NASA Press Release 02-030, February 5, 2002
NASA Satellite, Called "TIMED," Launched to Study Sun-Earth
Interaction
http://stp.gsfc.nasa.gov/missions/timed/timed.htm
www.timed.jhuapl.edu
The Sun's Dark Secret: How Sunspots Pull Themselves
Together
http://www.gsfc.nasa.gov/topstory/20010919sunspot.html
Largest Sunspot Group in a Decade
The largest sunspot group in a decade appeared on the Sun in late
March and early April, and led to giant solar flares and beautiful
aurorae. Images appear at
http://www.noao.edu/outreach/press/pr01/img0101.html
The Sun's Magnetic Pole has Flipped
The north and south magnetic poles of the sun have flipped, as they
do every solar maximum. So the solar maximum is really here. See the
sunspot diagram and a magnetic butterfly diagram.
spacescience.com/headlines/y2001/ast15feb_1.htm
Solar Constant On-Line
http://www.pmodwrc.ch/solar_const/solar_const.html
from the World Radiation Center in Davos, Switzerland.
The Sun On the Web, Minute by Minute
http://www.spacew.com/sunnow.
The web page is automatically updated with the latest image every
minute.
MPEG movies based on the last 60 received images are updated every 30
minutes and are available at:
http://www.spacew.com/sunnow/sunmovie.html
http://www.spacew.com/sunnow/archive/2000.Solar B Spacecraft for 2005
See
http://wwwssl.msfc.nasa.gov/ssl/pad/solar/solar-b.htm
San Fernando Observatory Web Site
Eclipse, Satellite Solar Slides
Solar Eclipse Educational NASA Web Site
Elizabeth Newton (NASA/Marshall)
Jim Miller (Univ. of AL in Huntsville)
Space Weather On Line
