Betelgeuse observed with the Atacama Large Millimeter/submillimeter Array (ALMA). In the millimeter continuum the star is around 1400 times larger than our Sun. The overlaid annotation shows how large the star is compared to the Solar System [ALMA (ESO/NAOJ/NRAO)/E. O’Gorman/P. Kervella]

All About Betelgeuse. How Big Is It?

Thanks to interferometric observations made since 1920, we know the angular diameter of Betelgeuse with high precision. However, our knowledge of the linear diameter is less precise because our knowledge of Betelgeuse’s distance is uncertain. The most accurate estimates available today tell us that the diameter of the red supergiant is approximately 1.4 billion km

A 56-year-long suicide attempt

On page 23 of the first volume of a popular book of 1923 entitled Hutchinson’s Splendor of the Heavens, a curious drawing appears. There is a boy who shoots a shotgun and an older man who looks in the opposite direction and is about to be hit by the bullet after it has traveled the entire circumference of Betelgeuse. The caption inside the image says that if a 14-year-old fired a shotgun, he would have to wait until he was 70 years old for the bullet he fired to complete a full circle around the star [1].