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If you’ve ever looked up at the night sky and spotted a bright reddish star in the constellation Orion, chances are you’ve seen Betelgeuse. This glowing red star sits on Orion’s shoulder and has fascinated people for generations — not just because of how bright it is, but also because of how strange and unpredictable it can be.
So, What Exactly Is Betelgeuse?
Betelgeuse (pronounced “Beetle-juice”) is a red supergiant — a massive, aging star that’s coming to the end of its life. Even though it’s only about 10 million years old (compared to our Sun’s 5 billion years), it burns through its fuel so quickly that it’s already on its way out.
This star is huge. If Betelgeuse were to replace our Sun, its immense size would extend its outer edge all the way to Jupiter’s orbit! This colossal star is roughly 700 times larger in diameter than the Sun and radiates between 7,500 and 14,000 times more light. Yet despite all that brightness, Betelgeuse is actually cooler than the Sun, with a surface temperature around 6,000°F — the Sun’s is closer to 10,000°F.
Betelgeuse sits approximately 700 light-years away from Earth, so the glow we observe from it tonight began its journey through space around 700 years in the past!
A Star Full of History
Betelgeuse has been known and admired since ancient times. The Egyptians, Greeks, and even Indigenous Australian cultures included it in their sky stories. In modern astronomy, it was named Alpha Orionis by German astronomer Johann Bayer in 1603 because it was believed to be the brightest in the Orion constellation (though now we know Rigel is actually brighter).
Astronomers noticed long ago that Betelgeuse doesn’t shine at the same level all the time — it gets brighter and dimmer in a regular pattern. It usually has a brightness cycle of about 400 days, and a longer one that lasts about five years.
The Great Dimming Mystery
In late 2019, something strange happened. Betelgeuse started dimming a lot — far more than usual. By early 2020, it had lost about 60% of its brightness. This sudden change led many scientists (and skywatchers) to wonder: Is Betelgeuse about to explode?
But just as suddenly as it dimmed, Betelgeuse brightened back up again by April 2020. So what really happened?
Thanks to telescopes like NASA’s Hubble, scientists discovered that Betelgeuse had actually blown off a huge chunk of its surface. That material formed a dust cloud, which blocked the light from reaching Earth and caused the star to appear much dimmer.
This kind of eruption is similar to what our Sun does (called a coronal mass ejection), but Betelgeuse’s outburst was enormous — It unleashed hundreds of billions more mass than a standard solar flare—equivalent in weight to multiple Moons!
What’s Next for Betelgeuse?
Despite all the excitement, scientists don’t think Betelgeuse will explode any time soon. It still likely has about 100,000 years left before it goes supernova — which is when a star dies in a dramatic explosion. When Betelgeuse eventually reaches the end of its life, it might collapse into either a neutron star or possibly form a black hole.
For now, astronomers continue watching it closely using space telescopes, especially the Hubble, which can see in ultraviolet light and helps scientists study the outer layers of the star.
Even though Betelgeuse is unpredictable, it gives us a rare chance to study the life and death of giant stars up close. And for the rest of us? It remains a breathtaking testament to the incredible and unpredictable nature of our universe.
