The ways in which we imagine one of the most well-known stars in the night sky are being called into question by a new simulation.
Sometimes not among the top 20 brightest stars, Betelgeuse is a red supergiant, the final stage of stellar evolution before a supernova.
Usually, stars are enormous plasma balls, but a recent simulation suggests that red supergiants are not.
Its radius is at least 640 times the solar radius and might reach 1,000 times if placed in the solar system, stretching past Jupiter's orbit.
A few hundred million suns would fit in that volume, but its mass of 15 suns shows exceptionally low outer layer density.
We can see characteristics on Betelgeuse's surface at 500 light-years away.
Those features could indicate the star's rapid rotation or surface change.
Both are feasible, but each needs more.