What’s squeezing Betelgeuse?

National Geographic breaks the worrying news that Betelgeuse is shrinking:

Researchers at the University of California, Berkeley, first measured the star in 1993 with an infrared instrument on top of Southern California’s Mount Wilson. They estimated the star to be as big around as Jupiter’s orbit around the sun.

But measurements made since then using the same instrument show that Betelgeuse is now only about as wide as the orbit of Venus—a size reduction of about 15 percent in 15 years.

The cause of the star’s rapid contraction is a mystery. But the team noted that they had observed an unusual big red spot on the star three years ago.

They say it could go supernova at any time.

Poor giant star.