Betelgeuse, the bright red supergiant star marking the shoulder of the constellation Orion, is nearing the end of its life. This enormous star, hundreds of times larger than our Sun, is destined to end in a spectacular explosion known as a supernova. When this happens, the night sky will be transformed, offering a profound visual change to one of the most recognizable constellations.
Understanding Betelgeuse and the Explosion Timeline
Betelgeuse is classified as a red supergiant, meaning it has exhausted the hydrogen fuel in its core and is now fusing helium into carbon and oxygen. Estimated to be around 642 light-years from Earth, this immense star is rapidly approaching its final evolutionary stages. For a star of this mass, the burning of heavier elements progresses quickly, with the final stage of silicon burning lasting only days before the core collapses.
The explosion, known as a core-collapse or Type II supernova, is Betelgeuse’s inevitable fate. However, the exact timing remains uncertain for astronomers. Current models suggest the star is likely to explode within the next 10,000 to 100,000 years, though there is a chance it could happen much sooner.
The distance of 642 light-years means the light we see today left the star centuries ago. If Betelgeuse were to explode tonight, the light from that event would not reach Earth for hundreds of years. The explosion could have already occurred, and we are simply waiting for the light to travel across space.
How Bright the Supernova Will Be
The Betelgeuse supernova will be a Type II-Plateau event, characterized by a rapid increase in brightness followed by a plateau phase that lasts for several months. When the light from the explosion finally reaches Earth, the star’s apparent magnitude will dramatically increase from its current variation of around +0.5 to a peak of approximately -10 to -13.
The supernova will likely rival the luminosity of the half-Moon, and possibly the full Moon, making it the second-brightest object in the night sky. The event will be easily visible during the day for several weeks, appearing as a brilliant, star-like point of light even against the Sun.
The color of the star will shift dramatically from its current reddish-orange hue to a brilliant, intense blue-white. This color change is due to the extreme heat of the supernova shockwave. The star’s peak brightness is expected to last for a few weeks before slowly fading over the next few months, forever changing the familiar shape of the Orion constellation.
What Happens After the Stellar Explosion
Concerns about the supernova causing harm to Earth are unfounded due to the star’s considerable distance. Betelgeuse is well outside the “lethal zone,” which is considered to be within 50 to 100 light-years for a supernova’s most dangerous radiation.
Although a burst of high-energy radiation, including gamma rays, will be released, the Earth’s atmosphere and the vast distance of over 600 light-years will harmlessly attenuate it. The initial blast of radiation and cosmic rays will be significantly reduced, posing no threat to life or the ozone layer.
The ultimate fate of Betelgeuse’s core will be a compact stellar remnant, most likely a neutron star that may spin rapidly as a pulsar. This dense object will be surrounded by the expanding cloud of gas and dust ejected during the explosion, forming a spectacular, colorful supernova remnant or nebula.
This nebula will remain visible in the sky for thousands of years, a permanent and beautiful memorial marking the spot where the star once shone. After the initial period of extreme brightness, the night sky will gain this new, slowly expanding cloud, enriching the galaxy with heavy elements.