* Astronomy

In 1969, while looking back over Vela 4 data just prior to the launch of Vela 5 satellite, Ray Klebesadel and Roy Olsen found an event recorded by Vela 4a,b on July 2, 1967 which also triggered the still operational Vela 3 satellites. The event appeared to be a cosmic gamma-ray burst but at the time the constellation of satellites did not have sufficient timing resolution at the trigger to make a good determination of direction to the burst source. In retrospect, this event had a time history similar in appearance to the later recognized cosmic bursts. Klebesadel believes that this event represents the "first observed gamma-ray burst". The Vela 4 a and b data was used to construct a time history of this event which was published in Scientific American, Oct. 1976. No earlier observation of a similar event is known.
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