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Aurora Science

  • Why Do We See Red in the Sky?
    Auroras get their color from the various elements in our atmosphere, like oxygen and nitrogen. When charged particles from the sun hit theses elements, they excite the atoms, causing them to give off light. Different atoms give off different colored light when they become excited, as this animation shows.
  • X-ray Images of the North Polar Region from the Chandra HRC-I Instrument
    Here are X-rays images (shown on the same brightness scale) of the north polar region obtained by Chandra HRC-I on different days, showing large variability in soft (0.1-10.0 keV) X-ray emissions from Earth s aurora. Note that the images are not snap shots, but are ~20-min scans of the northern auroral region in the HRC-I field-of-view. The brightness scale in Rayleighs (R) assumes an average effective area of 40 cm2. The day-night terminator at an altitude of 0 km is displayed with lighting. The day-night terminator at an altitude of 100 km is shown by the blue line.

Aurora from the Ground

  • THEMIS/ASI Nights - High Resolution

    A collection of ground-based All-Sky Imagers (ASI) makes an important component of the THEMIS mission in understanding the interaction of the magnetosphere and aurora. It is sometimes referred to as the sixth THEMIS satellite. Descriptions of the instruments are available on the THEMIS-Canada Home Page. Imagery from each camera is co-registered to the surface of the Earth and assembled into a view of the auroral events.

    This movie presents data from the first large auroral substorm since the THEMIS launch. The substorm reached its maximum between 6:00 and 7:00 UT.

    Note that the ASI data in this movie are assembled from significantly higher resolution datesets than the earlier version, THEMIS/ASI Nights. The higher resolution enables you to see much finer details in the aurora structure. In addition, one notices trees circling the horizon visible to the cameras located in western Canada.

  • Aurora Imagery from Poker Flats
    The northern lights were dancing across the sky over Alaska the night of Feb. 16 as seen from the Poker Flat Research Range north of Fairbanks. While skies were clear at Poker and the auroras were active, cloudy skies over downrange viewing sites prevented the launch of NASA sounding rockets carrying instruments to explore the Earth's magnetic environment and its impact on Earth’s upper atmosphere and ionosphere. Special ground-based instruments are located at the downrange sites for observing the aurora into which the rockets fly. The launch window for the four sounding rockets runs through March 3. Credit: NASA/Terry Zaperach

Aurora from Space

  • Auroral Substorm from Polar

    This movie is an auroral substorm event observed by the visible light camera aboard the Polar spacecraft.

    Because the visible light camera records in a single broad range of wavelengths, we do not have color imagery of the event. For this movie we will color the aurora green since that is the dominant color in most cases. The VIS camera is also low resolution so the fine aurora details visible from the ground are not apparent in this movie.

  • Polar Visible Aurora Animation: July 16, 2000
    An animation of the visible aurora in the northern hemisphere on July 16, 2000 as measured by Polar. Text on preview image reads, "Polar Visible Aurora
    July 16, 2000".
  • THEMIS Sees Magnetic Reconnection
    THEMIS observations confirm for the first time that magnetic reconnection in the magnetotail triggers the onset of substorms. Substorms are the sudden violent eruptions of space weather that release solar energy trapped in the Earth's magnetic field.