Betelgeuse, the bright, red star in the constellation Orion, has been behaving strangely lately. In late 2019 and 2020, it became much fainter than usual – almost 60% dimmer than its normal brightness.
This event, known as the “great dimming”, sparked speculation that the star might be about to explode as a supernova. But then Betelgeuse brightened again, and for a few days in 2021, it was even brighter than ever before. What is going on with this star? And what would the consequences be if it did explode?
Betelgeuse is one of the brightest stars in the night sky, and one of the largest and most luminous stars known. It is a red supergiant, a type of star that has exhausted its core hydrogen fuel and expanded to hundreds of times its original size.
Betelgeuse is so big that if it replaced the Sun in our solar system, it would engulf Mercury, Venus, Earth and Mars.
Red supergiants are also variable stars, meaning that they change their brightness over time. This is because they pulsate, expanding and contracting due to changes in their internal structure and temperature. Betelgeuse usually varies between being the seventh and tenth brightest star in the sky, but sometimes it can become even fainter or brighter.
The great dimming of Betelgeuse was caused by a combination of factors. First, the star was at its minimum brightness due to its natural pulsation cycle. Second, a large cloud of dust and gas that the star had ejected obscured part of its surface from our view. Images of Betelgeuse showed that half of it was missing. Third, a change in the star’s magnetic field may have affected its brightness.
The great brightening of Betelgeuse was also related to its pulsation cycle. The star reached its maximum brightness due to its natural variation, but this time it was even brighter than usual. This may have been because the dust cloud had dissipated or moved away from our line of sight, allowing us to see more of the star’s surface.
These events do not necessarily mean that Betelgeuse is about to explode. Red supergiants can live for millions of years before they die in a spectacular supernova explosion.
However, Betelgeuse is near the end of its life cycle, and astronomers estimate that it could explode anytime within the next 100,000 years.
If Betelgeuse did explode as a supernova, it would be an amazing sight from Earth. It would be as bright as the full moon, and visible even during the day.
It would remain visible for several months, gradually fading away. It would not harm us directly, as we are too far away from it to be affected by its radiation or shock wave. However, it would change the appearance of Orion forever, leaving a faint remnant in place of the red star.