Step outside tonight after the sun sets and gaze toward the southwestern part of the sky. Do you spot Orion’s Belt? Those three luminous stars—Alnitak, Alnilam, and Mintaka—are hard to miss. Yet, there’s another star catching your eye just above them, the deep red supergiant known as Betelgeuse. A standout in the winter sky for those in the northern hemisphere, Betelgeuse holds the title of the nearest red supergiant star to our solar system.
Betelgeuse, positioned on Orion’s “shoulder,” boasts a surface that’s constantly churning. It’s ranked as the tenth brightest star in our sky. However, recent studies have shown a noticeable decrease in its brightness by 0.5 magnitude since the end of January, as reported by EarthSky and Sky & Telescope. This leads to the burning question: Is Betelgeuse on the brink of explosion?
The thought of Betelgeuse exploding into a supernova is thrilling, yet it’s not expected to occur immediately. Astronomers predict it will happen within the next 100,000 years, which, in the grand timeline of stars, is quite soon. The last time a supernova was observed in our Milky Way was in the 17th century, making the potential explosion of Betelgeuse a highly anticipated event for astronomers.
A study from 2023 suggests that Betelgeuse might run out of its carbon fuel in less than 300 years, leading to a core collapse and a supernova explosion possibly within a few decades. This makes any minor changes in its brightness particularly intriguing.
Betelgeuse, also known as Alpha Orionis, is a colossal star, 20 times the mass of our sun and 1,400 times its size, situated 650 light years away from us. This means any events we’re witnessing now actually took place 650 years ago. But there’s no cause for alarm, as Betelgeuse is well outside the 50 light-year range considered dangerous for a supernova impact.
The star made headlines in late 2019 and early 2020 for its “great dimming,” where it dimmed to about 40% of its usual brightness before eventually returning to normal. This period also saw Betelgeuse changing its shape.
Known as a variable star, Betelgeuse’s brightness typically fluctuates over cycles of about 400 days and six years. However, the “great dimming” was an unprecedented event.
Several theories were proposed for this dimming, including a cold spot caused by convection in its southern hemisphere, normal brightness variations, or dust ejections, which are common for red supergiant stars.
Images from the Hubble Space Telescope later confirmed that a significant “burp” from within Betelgeuse had released a mass of material, forming a dust cloud that partially obscured the star’s light from our view.
In December of the previous year, Betelgeuse caught attention again when it was briefly eclipsed by asteroid 319 Leona, causing a “ring of fire” annular eclipse for about 12 seconds—a rare celestial event.
Eventually, Betelgeuse will meet its end in a spectacular Type IIP supernova explosion, shining as brightly as the full moon for several months, leaving behind a neutron star. This event would be visible even during the day and would offer a breathtaking night-time spectacle. For the best view, we’d need Betelgeuse to explode between December and April, before it dips below the horizon and out of sight.
Here’s to hoping for clear skies and wide eyes to witness such a marvel.