Stuart's Event, New Evidence

From: michael storch (chasidot@pobox.com)
Date: Tue Mar 04 2003 - 02:44:25 EST

  • Next message: Tony Beresford: "observations feb 27, March 4"

    {Something to inspire us all .....}
    
    The New York Times
    March 4, 2003
    A Flash From the Past: New Evidence Supports Moon Blast
    By HENRY FOUNTAIN
    
    Humans have gazed at the Moon in wonder since ancient times, but what Dr. 
    Leon Stuart observed one night in 1953 was more wonderful than what anyone 
    had seen before or since.
    
    Looking through his eight-inch telescope at his home near Tulsa, Okla., Dr. 
    Stuart, a radiologist by profession but an astronomer by avocation, saw and 
    photographed a bright flash on the Moon's surface.
    
    Dr. Stuart was certain that he had witnessed a small asteroid hitting the 
    Moon, the flash being the fireball from the event. An amateur astronomy 
    journal published his photograph and report, and it has remained a 
    curiosity over the years. While some scientists thought his explanation 
    plausible, others were convinced that he saw an optical aberration or a 
    much closer object, like a meteorite in Earth's atmosphere (or, 
    embarrassingly, an airplane passing overhead).
    
    Now new research shows that Dr. Stuart's flash on the Moon was no flash in 
    the pan. An astronomer at NASA's Jet Propulsion Laboratory, poring over 
    high-resolution lunar photographs, has found a fresh crater in the precise 
    area where Dr. Stuart saw his flash.
    
    "I think it's a very good candidate," Dr. Bonnie J. Buratti, an astronomer, 
    said of the crater, which is about 250 to 800 yards in diameter. Dr. 
    Buratti worked on the project with Lane Johnson, then a student at Pomona 
    College; the two have published their findings in latest issue of the 
    astronomical journal Icarus.
    
    At the Jet Propulsion Laboratory, Dr. Buratti served on the science team 
    for the Clementine spacecraft, which thoroughly photographed the Moon in 
    1994. As part of that work, she and others had looked for evidence of 
    transient phenomena like asteroid impacts and had found none. Just as they 
    were preparing a paper on their research, a colleague mentioned what is 
    known as Stuart's event.
    
    "I had never heard of it," Dr. Buratti said. But her curiosity was piqued, 
    so she found a 1953 copy of the amateur journal The Strolling Astronomer 
    and looked at the photo.
    
    She and Mr. Johnson were able to determine the approximate location of the 
    flash, a circular area with a radius of about 20 miles. From the brightness 
    of the event, they estimated the force of the impact to be about half a 
    megaton, equal to a small hydrogen bomb. Their best guess as to the size of 
    a feature created by such an impact, including a crater and its ejecta 
    blanket, the material thrown out around the sides, was 1.2 miles or less ? 
    too small to see from ground-based photographs.
    
    So first they looked at photographs taken by the lunar orbiters in the 
    1960's, which mapped areas of the Moon to prepare for the Apollo landings. 
    These photos were inconclusive, so they turned to the huge database of two 
    million images from Clementine. Many of these photographs were taken with 
    color filters, which can help in determining the age of a surface feature.
    
    On the Moon, material that is freshly exposed has a slight bluish tinge. 
    Over time, because of the constant bombardment of cosmic rays, other 
    high-energy particles and micrometeorites, the structure of the material 
    changes and iron particles tend to predominate, making the material 
    slightly red.
    
    In the Clementine photos, Dr. Buratti and Mr. Johnson found one small 
    crater that was "very, very blue and fresh appearing," Dr. Buratti said. It 
    also happened to be in the exact center of the area they were looking. And 
    it was the proper size ? slightly less than a mile across, including the 
    ejecta blanket. Dr. Buratti estimated the size of the asteroid at 20 yards 
    in diameter.
    
    She said that although there was a good deal of uncertainty in their study, 
    she was "about 90 percent" confident that the crater was the one created by 
    the fireball Dr. Stuart observed. "There's no other object that stands out 
    as a candidate," she said.
    
    Dr. Stuart, who died in the 1960's, was not one to make wild claims. "He 
    was very careful to eliminate all the other possibilities," she said. "At 
    the time, scientists didn't even agree that craters were caused by impacts. 
    So he was very conservative."
    
    If Dr. Stuart observed an asteroid impact, he saw something that was 
    extremely rare: a rock of that size hits the Moon only once or twice a 
    century, according to best estimates.
    
    But Dr. Buratti said she wasn't surprised there was a witness. "I would 
    contend that at any given time, some amateur or professional astronomer is 
    watching the Moon," she said. "With a blast of this sort, someone would be 
    likely to see it."
    
    Copyright 2003 The New York Times Company
    
    -30- Chasidot
    
    Ask not what your laptop can do for you,
    Ask what you can do with your necktop.
    
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