Animation of a supernova of Betelgeuse brightening over several nights. The animation simulates a view from the same position over several nights, with an image recorded at the same time each night. Betelgeuse rises in the sky over this period, and increases dramatically in brightness. Betelgeuse Alpha Orionis is a red supergiant star in the constellation Orion. It is a massive star that is burning its nuclear fuel extremely quickly, and has already run out of hydrogen and so swollen to become an enormous red supergiant. Betelgeuse is thought to be more than 18 times the Sun磗 mass and nearly 1200 times as wide, and just ten million years old compared to the Sun磗 five billion years. It is expected to explode as a supernova at any time within the next million years. When it does it will be the brightest object in the sky, outshining the moon, casting shadows and being easily visible in daylight. It could stay at that brightness for several months before dimming gradually. Its radiation is also causing gas in the Orion Complex to glow red. This is a massive starbirth region that has produced many of the bright stars in the constellation. Betelgeuse is thought to be around 640 light years from Earth, so its explosive death will not pose a hazard to life.