for National Geographic News
A powerful supernova hundreds of years ago sent light bouncing off neighboring dust clouds, and that "echoed light" is just now reaching Earth, providing clues to the spectacular event.
The massive blast took place 160,000 light-years away in the Large Magellanic Cloud galaxy.
New images of the light echoes, taken at Chile's Cerro Tololo Inter-American Observatory, provide the best look yet of a supernova explosion long after it was first visible from Earth.
In two recent studies, astronomers concluded that the supernova was visible from Earth around the year 1600 and was unusually bright and energetic.
(Read related story: "Brightest Known Supernova Detected" [October 15, 2007].)
What's puzzling scientists is why people apparently didn't see the original explosion 400 years ago.
In one of the studies, lead author Carles Badenes of Princeton and his colleagues note that European exploration of the Southern Hemisphere was well underway by that time, and navigators often studied the sky for guidance.
Several early scientists were even making star maps during this period. But no explorer, nor any of the colonized populations then established below the Equator, recorded seeing the blast, the researchers say.
"Such an event would be hard to miss by even the most inattentive observers," they write in the study.
"Even allowing for some incompleteness in the historical records, a spectacular astronomical event like a bright LMC supernova should have left some kind of trace if it happened at any time later than the beginning of the 17th century."
Both new studies on the supernova will be published in an upcoming issue of the Astrophysical Journal.
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