2001 SPACE SCIENCE VIDEOTAPES |
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Tape Title | Record ID | Date Produced | TRT: |
Synopsis |
| REVEALING THE SUN'S DARKEST SECRETS | G01-066 | 11/06/01 | 00:12:33 | What lies beneath those dark sunspots? And, with opposing magnetic fields rising up from them, why and how do they stay intact for days or even weeks? Thanks to the MDI instrument aboard the SOHO spacecraft scientists were able to solve a long-standing mystery and peer inside to see swirling flows of electrified gas (plasma) that create a self-reinforcing cycle that holds it all together. This may also help explain the brutal cycle that sends storms toward Earth that threaten high-tech systems.
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TAPE CONTENTS: |
| ITEM (1): Anatomy of a Sunspot - Why are sunspots so much cooler than the solar surface (photosphere)? Thanks to a method similar to an ultrasound, scientists found much hotter temperatures below the spot that seem to get trapped by magnetic fields forming a virtual bottleneck, making the spot much cooler than the surface. In the visualization, completely created from data of a June 1998 sunspot; red is hottest, followed by yellow; purple is cold.
Courtesy: NASA
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| ITEM (2): Internal Ebb & Flow - How do sunspots remain intact with opposite magnetic fields repelling each other? For the first time, scientists were able to confirm theories that inward flows of material stabilize the structure. With the MDI instrument, scientists observed the flows, seen here in an animation based on the June 1998 sunspot.
Courtesy: MDI / SOHO
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| ITEM (3): What Is a Sunspot? - Sunspots appear dark because they are cooler than the solar surface due to a strong magnetic field that traps the core's heat from travelling to the surface. The average sunspot is about 4500 degrees C (8132 F), while the surroundings are about 6000 degrees C (about 10,000 F). Sunspots can last for weeks or more and can be as large as 80,000 km (over 6 planet Earths).
Courtesy: NASA/ESA
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| ITEM (4): Ground-Level Observations - Equally valuable to solar studies are ground-based telescope views. The first image is from the Swedish Vacuum Solar Telescope (SVST) resting atop a volcano on the island of La Palma in the Canary Islands. The remaining are from the Big Bear Solar Observatory located in the middle of Big Bear Lake, California.
Courtesy: Swedish Vacuum Solar Telescope/Lockheed Martin, Big Bear Solar Observatory / NJIT
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| ITEM (5): Glancing Above The Sunspot - What is happening above the sunspot? The Transition Region and Coronal Explorer (TRACE) spacecraft caught these coils of hot, electrified gas, known as coronal loops above active sunspots. The loops (some more than 300,000 miles high and capable of spanning 30 Earths) rise while flowing along the solar magnetic field, then cool and crash back to the surface at more than 60 miles per second (100 kilometers per second).
Courtesy: NASA / Stanford Lockheed Institute For Space Research
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| ITEM (6): Why Worry About Sunspots? - Hot material called plasma can interact with the sunspot's magnetic fields and create violent explosions called flares. Energetic particles and radiation from these flares often result in coronal mass ejections (CMEs) that bombard Earth and can affect everything from radio communication to satellites and astronauts in space.
Courtesy: NASA
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| ITEM (7): The Sun's Active Cycle - Like the Earth, the Sun has seasons; 2000/2001 is generally considered the high point, or "solar max". A two to three year period when the Sun's activity is most complex and turbulent, the solar max can be seen in the comparison of 1996 and 2000 solar images. Sunspots are more likely to form during solar max, although even after the absolute peak,
Courtesy: NASA/ESA
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| ITEM (8): Galileo's Sunspots - Galileo Galilei was one of the first Europeans to study and record sunspots in 1611. Contrary to other theories, he believed that sunspots were part of the Sun itself, like spots or clouds. This was controversial because popular sentiment, based on the likes of Greek philosopher Aristotle, was that the Sun and heavens were perfect and unblemished.
Courtesy: Galileo Project, Rice University / Owen Gingrich
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| ITEM (9): Listening For The Answers - Scientists were able to pursue the inner-workings of the sunspot by listening to it through "acoustic tomography." Similar to an ultrasound diagnostic in medicine that uses sound waves to image structures inside the human body, it is an offshoot of the science of 'helioseismology'. That soundtrack can be used to calculate everything from solar density to temperature.
Courtesy: NASA / ESA
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| ITEM (10): Who's Listening? - The Michelson Doppler Imager (MDI) onboard the Solar and Heliospheric Observatory (SOHO) spacecraft allowed scientists to peer inside the Sun by detecting subtle distortions the sound waves create on the Sun's surface. The data helps deduce the location of active regions and give information about density, temperatures, chemical makeup and motions.
Courtesy: NASA/ESA
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