The star Betelgeuse has captured the imagination of astronomers and science fiction fans for decades. Its appearance in the constellation Orion makes it one of the most recognizable stars in the night sky. But how long will Betelgeuse continue to shine on our celestial stage? Here we explore the lifespan of this red supergiant and when we can expect its final curtain call.
What is Betelgeuse?
Betelgeuse is a red supergiant star located approximately 642 light years from Earth in the constellation Orion. It is one of the largest and most luminous stars visible to the naked eye. Betelgeuse has about 20 times the mass of our sun and a radius over 1,000 times larger. If placed at the center of our solar system, Betelgeuse would extend past the orbit of Jupiter.
Betelgeuse is nearing the end of its life cycle. It is currently in the late stages of stellar evolution and has swollen into a red supergiant as its core hydrogen fuel supply has been exhausted. Nuclear fusion continues in shells around the inert helium core, causing the star to expand outward dramatically. Betelgeuse has cooled and reddened as it aged, resulting in its distinct orange-red color.
How Long Has Betelgeuse Been Around?
Betelgeuse is estimated to be around 8-8.5 million years old – quite young in cosmic terms. Compare that to our sun’s current age of 4.6 billion years and expected lifespan of around 10 billion years. Massive stars like Betelgeuse fuse their fuel very quickly, allowing them to only shine for a few million years before meeting their demise. Their huge mass leads to very high core temperatures and pressures that drive a rapid rate of nuclear fusion.
So while Betelgeuse ranks among the biggest and brightest stars in our galaxy, it’s just a newborn by stellar standards. Its life burning brightly is fleeting compared to lower mass stars like our sun.
When Will Betelgeuse Die?
Astronomers estimate that Betelgeuse will meet its end sometime in the next 100,000 years. Given its known mass, age and rate of fuel consumption, stellar physics calculations point to its core hydrogen being exhausted within 100,000 years. The fusion in its core will cease at that point, leading to a catastrophic gravitational collapse and a supernova explosion.
Of course, 100,000 years is a very short time for a star. Betelgeuse may only have a few tens of thousands of years left before it goes supernova. We are seeing its final act play out on the cosmic stage.
Will Betelgeuse Go Supernova or Hypernova?
When Betelgeuse does finally run out of fuel and collapse, it’s not entirely clear how violent the resulting supernova will be. Its mass likely places it on the borderline between supernova and hypernova categories.
If under about 20 solar masses, we can expect a relatively normal Type II supernova explosion. The star’s outer layers would be ejected at high speeds while the core collapses into a neutron star or black hole. This would result in a very bright supernova that could be visible in the daytime sky for weeks or months.
However, some models show Betelgeuse may be more massive, up to 25 solar masses. This places it in the range for a hypernova explosion. In this more extreme scenario, the shockwave and energy released would be 10 times greater, likely leaving behind a black hole. This could result in an even more spectacular show than a run-of-the-mill supernova.
Either way, the light from this explosion will be a stunning sight and significant astronomical event when it reaches Earth some 600 years later. Betelgeuse’s supernova will potentially be the most observed in human history.
When Will We Notice Betelgeuse is Gone?
Betelgeuse’s eventual supernova will not immediately remove it from the sky. This is because its distance of over 600 light years means we are still observing it as it was 600 years in the past. So it could in theory go supernova tonight, but we wouldn’t know it for another 600 years.
Astronomers predict we will start to notice Betelgeuse significantly fading a few weeks or months before the supernova light reaches us. As the star runs low on fuel and starts collapsing under its own weight in the lead-up to the explosion, it will get dimmer. It may drop enough in brightness to be noticeable to the naked eye.
So one day in the not-too-distant future, Orion will appear to be missing one of its bright shoulder stars. This could be the first warning that Betelgeuse has finally met its explosive demise, before the light from the supernova itself arrives.
Will Betelgeuse Become a Black Hole?
If Betelgeuse has enough mass when it goes supernova, it is likely to form a stellar mass black hole as the remnant. Current models show that stars with masses somewhere above 15-25 solar masses will form black holes when their core collapses.
Lower mass stars can form neutron stars, but a star as massive as Betelgeuse will almost certainly collapse into a black hole. This will produce a black hole around 10-15 times the mass of our sun. Material falling into the black hole could also generate x-ray radiation for millions of years as Betelgeuse transitions to this new degenerate form.
So not only will the explosion of Betelgeuse be visible, but its remnant in the Orion constellation will likely be the nearest black hole to Earth that we’ve detected.
Will Life on Earth be Impacted?
Fortunately, Betelgeuse’s supernova is not expected to cause any major issues for life on Earth. At its distance of over 600 light years, the explosion does not pose a radiation threat or risk of stellar debris impacting our planet.
The supernova may emit higher levels of gamma radiation andneutrinos. But overall Earth will be far enough away that nosignificant impact on our atmosphere or biology is expected. The lightshow in the sky will be the main observable effect.
However, there is a slim chance a nearby supernova in the next 100,000 years could have effects reaching Earth. But astronomers are now monitoring stars that may pose an explosion risk within that timespan. It seems Betelgeuse can explode whenever it wants with minimal impact to life here. We will be anxiously awaiting the stellar spectacle.
Conclusion
The red supergiant Betelgeuse is destined to end its life in a supernova explosion sometime in the next 100,000 years when its fuel is exhausted. Current estimates put its mass on the cusp between supernova and hypernova categorization. When it does explode, it will put on a phenomenal cosmic lightshow visible from Earth. One day Orion will be missing its red shoulder star, giving us a somber warning hundreds of years before the blast wave reaches us. But have no fear – Betelgeuse’s finale might be spectacular, but it poses little threat to life on our pale blue dot so far away. We will simply enjoy the show when this celebrity star ends its tenure on the galactic stage.