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On-line Articles, News Stories

  • Dec 9, 2005. Earth's Magnetic Pole Drifting Quickly. By ALICIA CHANG, AP Science Writer. Excerpt: SAN FRANCISCO - Earth's north magnetic pole is drifting away from North America and toward Siberia at such a clip that Alaska might lose its spectacular Northern Lights in the next 50 years, scientists said Thursday. ...The magnetic poles are part of the magnetic field generated by liquid iron in Earth's core and are different from the geographic poles, the surface points marking the axis of the planet's rotation. Scientists have long known that magnetic poles migrate and in rare cases, swap places. Exactly why this happens is a mystery. "This may be part of a normal oscillation and it will eventually migrate back toward Canada," Joseph Stoner, a paleomagnetist at Oregon State University, said Thursday at an American Geophysical Union meeting. Previous studies have shown that the strength of the Earth's magnetic shield has decreased 10 percent over the past 150 years. During the same period, the north magnetic pole wandered about 685 miles out into the Arctic, according to a new analysis by Stoner. ...At the present rate, the north magnetic pole could swing out of northern Canada into Siberia. ...
  • April 5, 2005. NASA RELEASE: 05-089. NASA Study Finds Earth's Auroras Are Not Mirror Image. Scientists looking at the Earth's northern and southern auroras were surprised to find they are not mirror images of each other, as was once thought. The main cause behind the differences appears to be the interaction between the Sun's outer atmosphere and the Earth's magnetic field. Analysis of the images from NASA's Polar spacecraft and the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) spacecraft showed how the auroras move and change, based on the "tilt" of the Earth's magnetic field toward the Sun and conditions in the solar wind. By knowing how auroras react to the solar wind, scientists can better determine the impacts of space weather in the future. The new discovery by scientists from NASA, the University of Iowa, Iowa City, and the University of California at Berkeley, shows that auroras may be more complicated than previously thought. The NASA-funded study appeared in a recent issue of Geophysical Research Letters. See also
    http://www.nasa.gov/vision/earth/lookingatearth/dueling_auroras.html
  • 1 Mar 2005. The Cosmologist and the Aurora - Essay by Dr. Sten Odenwald (NASA scientist) about the Northern Lights as he was observing them in Norway in winter of 2004.
  • February 16, 2005. Saturn's Auroras. Images of Saturn's polar aurora were taken by NASA's Hubble Space Telescope on Jan. 24, 26, and 28. ...The images were obtained during a joint campaign with NASA's Cassini spacecraft to measure the solar wind approaching Saturn and the Saturn kilometric radio emissions. The strong brightening of the aurora on January 26 corresponded with the recent arrival of a large disturbance in the solar wind.
  • Nov 8, 2004 Aurora Images:
    http://www.extremeinstability.com/04-11-8.htm
  • November, 2004. Aurora Gallery
    http://www.spaceweather.com/aurora/gallery_01nov04_page3.htm
  • Oct 2004. Aurora: Lights of Mystery. ...the aurora borealis, through the cameras of two extraordinary photographers, Hugh S. Rose and Patrick J. Endres, who live beneath these awesome northern lights. Collection of photos only available as an electronic download file: http://www.secondnaturecd.com/2nd/aurligofmyst.html
  • Jan 2, 2004. Auroras: Dancing in the Night, by Don Pettit. NASA Earth Observatory. If Iris, the goddess of the rainbow, had a sister she would be the goddess of Aurora. Glowing green ripples form arcs that constantly transform their shape into new glowing diaphanous forms: there is nothing static about aurora. It is always moving, always changing, and like snowflakes, each display is different from the last. http://earthobservatory.nasa.gov/Study/ISSAurora/
  • July 8, 2002 Auroras Underfoot -- A group of astronauts will never forget the day they flew right through a cloud of auroras.
  • October 25, 2001 EARTH'S AURORAS MAKE RARE JOINT APPEARANCE IN A FEATURE FILM Scientists using NASA's Polar spacecraft have captured the first-ever movie of auroras dancing simultaneously around both of Earth's polar regions. During a space weather storm on October 22, Polar's Visible Imaging System observed the aurora borealis and aurora australis (northern and southern lights) expanding and brightening in parallel at opposite ends of the world. The images confirm the three-century old theory that auroras in the northern and southern hemispheres are nearly mirror images - conjugates - of each other.
  • Nov. 19, 2001 IT'S ABOUT TIMED: NASA SPACECRAFT WILL
    USE LOFTY PERCH TO STUDY GATEWAY TO SPACE
    A NASA mission will soon reveal the well-kept secrets of a mysterious region situated 40 to 110 miles (about 60 to 180 kilometers) above the Earth called the Mesosphere and Lower Thermosphere/Ionosphere (MLTI), where electrical currents surge and auroras cast an eerie glow over the Northern and Southern hemispheres. RELEASE: 01-226 Mission site:
    http://stp.gsfc.nasa.gov/missions/timed/timed.htm
  • Nov 7, 2001. Aurora Lights up the Sky (Nov/01) -- Imelda Joson. The Sun's current sunspot cycle may be on the decline but our nearest star still continues to pack a lot of punch to the delight of aurora watchers worldwide. At 16:20 Universal Time on Sunday, November 4th, a powerful X-class flare unleashed a fast-moving coronal mass ejection.
  • Nov. 6, 2001 THE SUN'S DARK SECRET: HOW SUNSPOTS PULL THEMSELVES TOGETHER 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.RELEASE: 01-216
  • 25 July 2001 NASA's Wind spacecraft flies through Earth's magnetic tail and captures rare event in action
  • May 1, 2001, Space Weather on Mars [Science@NASA]
  • April 11, 2001 Hubble Spots Mysterious Flash of Light on Jupiter
    A brief but bright flash of light as big as Earth spotted near Jupiter's north pole by the Hubble Space Telescope has scientists stumped.
  • SUN UNLEASHES RECORD SUPERFLARE, EARTH DODGES SOLAR BULLET -- NASA RELEASE: 01-66
  • Apri 1, 2001 A massive coronal mass ejection afew days earlier resulted in unusual displays of aurora at lower latitudes. Wayne Narron, Northern Lights field tester, captured a photo from 30° north latitude.
  • March 27, 2001 COLLIDING SOLAR ERUPTIONS PACK
    POWERFUL MAGNETIC PUNCH -- RELEASE: 01-56
  • March 8, 2001 POSTCARDS FROM JUPITER: NEW AURORA DETAILS SEEN
  • December 15, 2000 Hubble sees satellite footprints in Jupiter aurora
  • 18 December 2000 Uncovering the mysteries of Jupiter's aurora
  • Dec 14, 2000 Satellite Footprints Seen in Jupiter Aurora
  • Nov 2000, Sky & Telescope magazine, review of Aurora Monitor software that predicts potential aurora activity. p. 72. http://solar.spacew.com/aurora/
  • Jupiter Auroral Campaign Dec. 2000
  • February 4, 1999 SOHO SPACECRAFT DETECTS SOURCE
    OF HIGH-SPEED SOLAR "WIND" -- RELEASE: 99-11

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More activities

  • Want More Sun? Planetarium Activity "Going Further" on the concept of Midnight Sun: Time the duration of daylight with wristwatches or stop watches at a sequence of locations from the equator north (or south). It is sufficient to time the Sun's travel from the meridian to sunset and double the result. The idea of this activity is in the Proceedings of the 35th Annual Conference of the Middle Atlantic planetarium Society (MAPS) May, 2000,by Sam Storch, Director of the Hubble Planetarium in Brooklyn, NY, and based on an idea by George Reed. Here are some locations to use:
    0° Equator; 10°N Port of Spain, Trinidad; 20°N Mexico City; 26°N Miami, FL; 28°N Cape Canaveral; 30°N New Orleans, LA; 34°N Los Angeles, CA; 38°N San Francisco, CA; 40°N NewYork; 42°N Boston; 45°N Montreal; 47°N Quebec; 60°N Leningrad, Russia; 65°N Fairbanks, AK; 70°N Point Barrow, AK.
  • For Colors of the Aurora activity, p. 45--online spectra: http://www.colorado.edu/physics/2000/quantumzone/

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Hard Copy Articles

  • Burtnyk, Kimberly, Anatome of an Aurora , Sky & Telescope magazine, March 2000. L Eather, Robert H., An Aurora Watcher's Guide, Sky & Telescope magazine, March 2000.
  • Frank, Adam, Blowin' in the Solar Wind, Astronomy magazine, Oct 1998, p. 60. Scientists are using the latest satellites and supercomputers to predict the onslaught of space storms.

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Books

  • Jago, Lucy, The Northern Lights, Alfred A. Knopf, New York, 2001. True story of Kristian Birkeland and his theories about the aurora borealis.
From Astronomy magazine, March 2000, p. 97:
Question: Earth's magnetic field has flip-flopped in the past. If this were to happen today, would it happen gradually or suddenly, and what would be the effect on life?
Charles Harrison, Rogersville, MO.

Answer from Eugene H. Levy, University of Arizona: Earth's magnetic field has changed polarity many times throughout our planet's history. The record of these geomagnetic reversals is preserved in layers of sediment, in rocks formed from lava, and in the magnetization of the seafloor crust.

Geomagnetic reversals occur at random intervals, ranging from a few tens of thousands of years to more than a million years. On the average, the field revereses about once every 200,000 years. From a geological perspective, a reversal event occurs very quickly, taking about 5,000 years. During a reversal, the magnetic field does not completely disappear. Instead, the field dimishes to about 20% of its usual strength and temporarily takes on a relatively disordered strurcture.

Earth's magnetic field provides some shielding from cosmic rays, so during a reversal the cosmic radiation striking Earth increases. Because the atmosphere provides our main shield against cosmic rays, the increase in cosmic radiation is not a cause for alarm. Thjere is likely to be some effect on climate during a field reveresal. But we do not yet understand the mechanisms well enough to predict the nature or magnitude of the effects.

Although there ar likely to be some minor effects on life, including possible small increases in mutation rates induced by the moderate increase in cosmic rays, there is not evidence that magnetic reversals have a significant negative effect on life. Organismsthat rely on magnetic orientation during migration might be disrutpted. But reversla events are so slow thaqt some adaptation is likely to occer.

The last major reversal occurred about 700,000 years ago, when human ancestors already were relatively advanced. During the 3 million years that have elapsed since the time that putative humanoid ancestors dwelled in Africa, Earth's magnetic field has reversed about a doaen times with no significant disturbance to life.

Earth's magnetic field changes slowly during a reversal event. Even in normal times, the intensity of Earth's magnetic field commonly varies by as much as 50 % over a few thousand years. In fact, while the magnetic field intensity has decreased a few percent over the past 100 years, there is no reason to believe that (and no way to tell if) Earth's magnetic field is entering a reversal phase. This decrease is probably just a reflection of normal "geomagnetic weather" and the intensity will likely increase in the future. But the pasts is a reliabloe guide to the future. It is virtually certain that Earth's magneticf field will reverse many times more in the future, with no cause for alarm.

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From Sky & Telescope magazine, March 2000 p. 24:
Ganymede Glows
Even if Galileo spacecraft hadn't discovered a magnetic field enveloping Ganymede, space physicists would still know that somthing odd was going on there. in recent years they have deduced that Jupiter's largest moon has a tenuous atmosphere of oxygen and ozone (O3) and a larger corona of atomic hydrogen. Spectroscopic observation by the Hubble Space Telescope in mid-1996 even revealed faint fluorescence from oxygen atoms at ultraviolet wavelengths. Their interest piqued by these prior discoveries, two research teams were recently surprised to find that the moon has a double glow: an ultraviolet emission at the poles and a distinctly red one around the equator.

A team led by Paul D. Feldman (Johns Hopkins University) and Melissa A. McGrath (Space Telescope Science Institute) used HST to image the faint ultraviolet auroras enveloping Ganymede's polar regions. the auroras result when electrons in Jupiter's magnetosphere flow along magnetic field lines leading tgoward the poles. There they break up oxygen molecules in Ganymede's tenuous atmosphere; the resulting excited oxygen atoms emit ultraviolet light at wavelengths of 1304 and 1356 angstroms.

Meanwhile, the wisps of gas surrounding Ganymede's midsection are fluorescing in red light bright enough to be seen by some future astronaut standing on the surface. Last Augusts, on two nights when Ganymede was in Jupiter's shadow, Michael E. Brown and Antonin Bouchez (Cal Tech) used the Keck I telescope to record the red light emitted by oxygen atoms at 6300 angstroms. Not an aurora in the usual sense, this emission is instead concentrated over the equator, a region protected by the moon's magnetic field from direct bombardment from the Jovian magnetosphere... 

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