"We really don't know," said Nobel Prize-winning physicist Charles Townes. "It's a puzzle."
Betelgeuse, about 600 light-years away according to NASA, has lost in its radius a distance comparable to the orbit of Venus, according to Townes.
[. . .]
Over the past 15 years, Townes said, Betelgeuse has shrunk in diameter more rapidly each year. It is the first time, using a consistent measuring tool, that scientists have noticed a marked change in the size of the red supergiant, said Berkeley physicist Edward Wishnow, who has studied the star with Townes for three years.
I'm struck by the prospect of an ET civilization engaged in some unguessable act of astro-engineering . . .
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