Betelgeuse: The Great Dimming and When it Might Supernova

Rebecca Jean T.
7 min readFeb 20, 2024

Recently, Betelgeuse has captured the interests of scientists and the general public alike because it has been seemingly dropping hints that it might be nearing its extinction. Because Betelgeuse is so massive, it is expected to undergo a dramatic explosion known as a supernova when it eventually runs out of the fuel powering it. The star is just close enough and big enough that its supernova would not only be detectible, it would actually be visible without a telescope for months, even during the day.

The reddish orange circle of Betelgeuse with four diffraction points sits in the center of the image. A black background full of white, blue, and orange stars.
Composite image of Betelgeuse created from exposures taken from the European Space Agency’s Digitized Sky Survey 2 (DSS2). Credit: ESO/Digitized Sky Survey 2. Acknowledgment: Davide De Martin.

The Great Dimming and Recent Brightening

Betelgeuse has been a long-time favorite of astronomers to observe. Located in the Orion constellation, Betelgeuse is visible to the naked eye as a reddish star in clear conditions. Betelgeuse sits some 700 light-years away from Earth but appears so bright because it is a red supergiant star near the end of its lifespan (more on that later).

In late 2019, astronomers began to notice that Betelgeuse looked notably smaller in the night sky. Previous observations from over 200 years of data on the star indicated a relatively predictable 400-day cycle of pulsing. Many stars, especially those in the later stages of life, tend to experience periods of fluctuation like this as their gases expand outwards before being pulled back in by the…

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Rebecca Jean T.

Published author on NASA’s Radio Jove project. Researching science topics to deliver to you in bite-sized stories.