As an early M-type supergiant, Betelgeuse is one of the largest, most luminous and yet one of the most ethereal stars known. A radius of 5.5 AU is roughly 7003118000000000000♠1180 times the radius of the Sun—able to contain over 2 quadrillion Earths (2.15 × 1015) or more than 1.6 billion (1.65 × 109) Suns.