SOLAR MAXIMUM IMAGES
OUR AMAZING CHANGING SUN
CAPTION:
The Sun is now believed to be at the peak of its eleven-year cycle of activity. Solar maximum is the two-to-three year period around that peak when the Sun's activity is most complex and turbulent, and the space around Earth is most disturbed. Notice the dramatic changes in the Sun's atmosphere from solar minimum in 1996 (left image) to solar maximum in 2000 (right image). These false color images were captured by the Solar and Heliosphereic Observatory's (SOHO) Extreme Ultraviolet Telescope (EIT) camera.
Credit: NASA/ESA
THE BASTILLE DAY STORM
The coordinated use of NASA and NOAA's tools were crucial to tracking and predicting the development of the most intense storm of the solar cycle, nicknamed the "Bastille Day event."
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CAPTION:
The "Bastille Day" storm began with a powerful x-class solar flare captured in this sequence by the Solar and Heliospheric Observatory (SOHO) Extreme Ultraviolet Telescope (EIT). The left image was taken just before the flare. Notice the rapid and intense variation in brightness associated with the flare (bright area in the middle image). The horizontal streak is just an effect in the EIT instrument caused by the intense brightness of the flare. The flare released streams of high-energy protons which peppered EIT's sensors just six minutes later (right image).
Credit: NASA/ESA
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CAPTION:
This sequence of images was taken just before, during, and right after a massive eruption from the Sun during the "Bastille Day" storm. The middle image shows a spectacular Coronal Mass Ejection (CME, an eruption of electrified gas from the surface of the Sun) billowing away from the Sun after the onset of the solar flare. The solid colored circle in the middle of each picture is the occulting disk of SOHO's LASCO camera. It blocks out the intense light of the Sun so that the tenuous corona is visible. "Halo events," are CMEs moving almost directly toward Earth. As they loom larger and larger they appear to envelope the Sun, forming a halo around our star. LASCO's cameras were peppered with high-energy protons (right image) associated with the earlier solar flare.
Credit: NASA/ESA
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CAPTION:
This closeup view of the "Bastille Day" flare was captured by NASA's Transition Region and Coronal Explorer (TRACE) spacecraft. The area in these images is about 186,000 miles across, large enough to span 23 Earths. The reference times for the three images (left to right, respectively) are 09:41, 10:23, and 12:31 UT, 14-Jul-2000. In the right image, we are looking down over a "slinky-like" formation of coronal loops, immense arches of hot, electrically charged gas that erupts from the Sun's surface and follows invisible lines of magnetic force in the solar atmosphere.
The image sequence shows a magnetic reconnection event that powered the flare. Magnetic reconnection occurs when oppositely directed lines of magnetic force become compressed and distorted in close proximity to each other. Much like a rubber band snaps suddenly if twisted too much, the distorted magnetic field lines break and reconnect to oppositely directed lines, releasing tremendous energy.
At the beginning, (left image) overlying, tenuous, very hot coronal loops (invisible in this picture) are holding down the slightly cooler, denser, stretched-out loops in the magnetically active region. When the stress reaches a high enough level, the overlying magnetic field reconnects to the stressed loops themselves, releasing the tension like a lid blowing off a pressure cooker. The original cool loops fly outward, and their energy is released as heat (flare in middle image). The heat both raises the temperature and also causes more material to "boil out" of the surface of the Sun to fill the newly formed, relaxed loops (right image).
The image is false color and shows radiation emitted by gas at about 2.7 million degrees Fahrenheit.
Credit: NASA / Lockheed Martin Solar and Astrophysics Laboratory
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CAPTION:
Thirty-one hours after the initial flare and Coronal Mass Ejection (an eruption of electrified gas, called plasma, from the Sun), the Earth was at the height of an intense geomagnetic storm. The plasma's magnetic field interacted with Earth's, allowing the solar wind energy to enter our magnetosphere and generate spectacular auroral displays. This sequence was captured by the Polar satellite at the height of the storm. The false colors show intensity, and blackish-red represents areas with the most intense auroral activity. Notice the large area over the United States, extending as far south as Florida. This is a result of an exceptionally strong geomagnetic storm; auroral activity is usually seen only at high latitudes.
Credit: NASA / University of Iowa