Modern Solar MysteriesModern Solar Mysteries
Dr. David H. HathawayNASA/MSFC
National Space Science and Technology Center
Dr. David H. HathawayNASA/MSFC
National Space Science and Technology Center
As we learn more, and gain a deeper understanding of things, we uncover even deeper mysteries about he world we live in.As we learn more, and gain a deeper understanding of things, we uncover even deeper mysteries about he world we live in.
Ancient Solar MysteriesAncient Solar Mysteries
• Why does the sun move across the sky?• Where does the sun go at night?• When will the sun come north again
(and can we do something to help it)?• What evil have we done to cause the sun
to disappear in the middle of the day?
• Why does the sun move across the sky?• Where does the sun go at night?• When will the sun come north again
(and can we do something to help it)?• What evil have we done to cause the sun
to disappear in the middle of the day?
Recent Solar Mysteries(~100 years ago)
Recent Solar Mysteries(~100 years ago)
• What is the composition of the sun?• How old is the sun?• How does the sun produce its energy?• What are those spots?
• What is the composition of the sun?• How old is the sun?• How does the sun produce its energy?• What are those spots?
Sunspots and the Sunspot Cycle(Schwabe 1844)
The Latitude Drift of Sunspots(Carrington, 1858)
Solar Flares(First observed by Carrington in September 1859)
A Solar Flare at the Limb
Prominence Eruptions(The “Granddaddy”)
The Sun’s Hot Corona(Edlén 1939)
The Sun’s Hot Corona(Edlén 1939)
The surface of the sun is at 6000ºC (10,000ºF) while the corona reaches temperatures greater than 2,000,000ºC (3,000,000ºF).The surface of the sun is at 6000ºC (10,000ºF) while the corona reaches temperatures greater than 2,000,000ºC (3,000,000ºF).
The Solar Wind(Parker 1955)
Comet tails always point away from the sun. Sunlight itself cannot do this.The solar wind blows off of the sun at a speed of about 1,000,000 mph.
Coronal Mass Ejections(OSO 7 1973, Skylab 1974)
Three Major Mysteries1. What triggers solar flares, prominence eruptions, and coronal mass ejections?
2. What causes the 11-year cycle ofsunspots and solar activity?
3. How is the corona heated and thesolar wind accelerated?
Solar Magnetism:THE KEY TO UNDERSTANDING THE SUN
Solar Magnetic Fields Measuring Magnetic Fields
Modeling Magnetic Fields Predicting Magnetic Behavior
Measuring Magnetic Fields
The Solar Spectrum
The Zeeman Effect
Magnetic Field Measuring Instruments
The Marshall Space Flight Center Magnetograph Facility
Magnetograms and Solar Features
Solar Magnetic Fields
Sunspots Prominences/Filaments
Coronal Loops Coronal Streamers
Magnetic Fields in Sunspots
Coronal Loops
Coronal Loop Evolution
Post Flare Loops
Magnetic Fields and Solar Eruptions - Theory
Magnetic Fields and Solar Eruptions - Observations
Magnetic “Shear” and a Solar Flare
The Sun’s Magnetic Cycle
Hales’s Polarity Law
The Magnetic Butterfly Diagram
The Magnetic Dynamo1) Differential rotation stretches and
amplifies the magnetic field2) The rising magnetic flux tubes are
twisted by the Sun’s rotation
3) Surface flows redistribute the magnetic flux elements
Dynamo Modelling
In this model the 11-year period for the sunspot cycle is set by the speed of the meridional circulation.
Coronal Heating
Many small brightenings occurthroughout the lower corona
These brightening tend to occur whereopposite magnetic fields meet
Solar Wind Acceleration
The solar wind is heldto about half itsmaximum value in theequatorial regions wherecoronal streamers form.
Previous MissionsSkylab (1973) Solar Maximum Mission (1980-1989)
Spacelab 2 Mission (1985) Yohkoh (Japan/NASA 1991-2001)
Current MissionsUlysses (ESA/NASA – 1990) SOHO(ESA/NASA – 1995)
TRACE (NASA – 1998) RHESSI (NASA –2002)
Future MissionsSTEREO (NASA -2005/11)
Solar-B (Japan/US/UK –2005)
Solar Dynamics Observatory(NASA -2008/04)
The Bastille Day Event - TRACE
The Bastille Day Event -SOHO
For More Information See:
science.nasa.gov