Astronomy Picture of the Day . ... Consider this "star in a box". Of course, the box is actually a computational box consisting of a three dimensional grid of points, and the star is a virtual one whose physical properties and internal dynamics are numerically simulated at the points on the grid. ... This picture is a movie frame from a recent numerical simulation of a supergiant star with properties intended to approximate the real star Betelgeuse . ... U. Based on Astronomy Picture Of the Day . ...