Here’s a fun idea: if you do a headstand tonight and look towards the east, you can see Betelgeuse (colloquially pronounced Beetlejuice, like the 1988 Tim Burton comedy-horror classic), the left shoulder of the Orion constellation. The star glows red, is fairly bright and if its recent behaviour is anything to go by, it might explode tonight... or in half a million years.
Over the past few months, this red star has been reducing in brightness to the point that avid stargazers can now notice it dimming with the naked eye, like a candle sizzling at the end of its wick. A lot of stars die a dramatic death in the form of a supernova, some of the most powerful explosions in the universe, and Betelgeuse might be well on its way to giving us a good light show.
At a hefty 15-times the mass of our sun, the “Juice” is the James Dean of stars: its excessive use of its fuel gives it a very short lifespan no more than 10 million years. Our sun, Sol, which is halfway through its 10-billion-year lifespan, is far more frugal with its fuel spend.
Stars resist death by cooking hydrogen and helium to produce a tug-of-war between gravity contracting it, and heat pressure expanding it. From earth we see only a warm glow or twinkle of a giant ball of flaming plasma.
Betelgeuse is also quite large, over a thousand times bigger than the Sun. It is a red supergiant that would almost engulf the orbit of Jupiter if it were ever transported to our solar system.
If it were to go supernova soon, as many hope, the resulting explosion would be the brightest object in the night sky. From the safety of earth, we would enjoy the spectacle as it becomes so bright at night that it would cast shadows much like the full moon, and still be visible during the day. And this beautiful sight would go on for several weeks, up to a few months, astronomers speculate.
But to dash the excitement for those of us who like a good detonation, the star is probably just dimming due to the weird physics of variable stars, which change their brightness periodically. In fact, variable stars are sometimes referred to as “standard candles” – the milestones used by astronomers to measure large distances in the universe.
To further drive the point home with the candle metaphor, it is as if Betelgeuse is a candle taking a little breather, with a flickering of the flame before the candle brightens up the room again.
This sudden dimming is a great opportunity to see astrophysics in action, processes that usually take hundreds of thousands of a typical human lifetime.
A similar explosion occurred in the year 1054 AD, which resulted in the formation of the Crab Nebula, a fantastic sight that you should look up in the Hubble Telescope images right now. The resulting explosion was not as spectacular for the people alive then, as astronomers expect Betelgeuse’s death will be for us or future stargazers.
While the Crab Nebula supernova occurred over 6,000 lightyears away, Betelgeuse is a mere 600 lightyears from Earth, which means if we see it explode tonight, it would have exploded over 600 years ago and took that time to reach us.
Even if Betelgeuse does not explode in our lifetimes, it is still an incredible sight, glowing red, expanding and contracting, flickering into dimness and flaring up in brightness.
No matter how long this tug-of-war between life and death continues, it is inevitable that Betelgeuse will go kaboom and when it does, I hope there will still be intelligent life on earth to see and appreciate it.
For now, our best hope of seeing it do its thing, is for us to look up, make a wish and say its name three times.
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