Have you ever looked at the night sky and wondered about the stars? Some of them are bright and white, some are faint and blue, and some are big and red. One of the most famous red stars is Betelgeuse, a giant star that is so huge and bright that it can be seen from Earth with the naked eye. But Betelgeuse is not just a pretty sight. It is also a star that is about to die in a spectacular explosion. In this article, we will tell you everything you need to know about Betelgeuse, the red giant that might explode soon.

What is Betelgeuse?

Betelgeuse is a star in the constellation of Orion, the hunter. It is the second-brightest star in Orion, after Rigel, and it marks the right shoulder of the hunter (or the left shoulder, as seen from Earth). Betelgeuse is a red supergiant star, which means it is huge and cool compared to other stars. It is about 10 million years old, which is very young for a star. However, because it is so massive, about 15 to 20 times the mass of the Sun, it has burned through its fuel very quickly and is nearing the end of its life. Betelgeuse is expected to explode as a supernova within the next 100,000 years, making it one of the brightest objects in the sky for several months.

Betelgeuse is also a variable star, which means its brightness changes over time. It has a regular cycle of about 420 days, during which it varies from magnitude +0.0 to +1.6. However, it also has irregular fluctuations that can make it much brighter or dimmer than usual. For example, in late 2019 and early 2020, Betelgeuse dimmed by more than 50%, reaching its lowest brightness in recorded history. This sparked speculation that it might be about to go supernova, but it turned out to be a normal variation caused by dust and pulsations on the star’s surface.

How big is Betelgeuse?

Betelgeuse is one of the largest stars ever discovered. It has a radius of about 700 to 1,000 times that of the Sun, which means it would engulf the orbits of Mercury, Venus, Earth, and Mars if it were placed at the center of our solar system. Betelgeuse is so big that it is not a perfect sphere, but rather a distorted shape that bulges and shrinks due to its rotation and convection.

To get a sense of how big Betelgeuse is, here is a table that compares its size to some familiar objects:

As you can see, Betelgeuse is enormous, and it would take a long time to travel around it. For comparison, it takes about 8 minutes for light to travel from the Sun to the Earth, but it would take about 4 hours for light to travel around Betelgeuse.

What will happen when Betelgeuse explodes?

Betelgeuse is a candidate for a supernova explosion, which is the most powerful and spectacular event in the universe. A supernova occurs when a massive star runs out of fuel and collapses under its gravity, releasing a huge amount of energy and matter into space. The resulting shockwave and radiation can outshine an entire galaxy for a brief period, and create new elements and cosmic dust that enrich the interstellar medium.

Betelgeuse is likely to explode as a Type II supernova, which is the type that occurs when a star has a core of iron. When the iron core reaches a critical mass, it can no longer support the weight of the outer layers, and it implodes in a fraction of a second. This triggers a nuclear fusion reaction that produces heavier elements, such as nickel and cobalt and releases a burst of neutrinos. The neutrinos carry away most of the energy, but they also heat the surrounding material, causing it to rebound and explode outward. The explosion ejects the outer layers of the star at speeds of up to 10% of the speed of light, creating a bright and expanding shell of gas and dust called a supernova remnant.

When Betelgeuse goes supernova, it will be visible from Earth even during the day, and it will be as bright as the half-Moon at night. It will remain visible for several months, gradually fading and changing color as the supernova remnant cools and expands. It will also emit various types of radiation, such as gamma rays, X-rays, ultraviolet, visible, infrared, and radio waves, providing valuable information to astronomers about the star and its environment.

However, there is no need to worry about the effects of Betelgeuse’s supernova on Earth. Even though Betelgeuse is relatively close to us, it is still far enough that the radiation and shockwaves will not harm us or our planet. The only impact will be a spectacular light show in the sky, and a new opportunity to learn more about the life and death of stars.

Who discovered Betelgeuse?

Betelgeuse has been known to humans for a long time, as it is one of the most prominent stars in the night sky. It was named by the Arabs, who called it يد الجوزاء (yad al-jawzāʾ), meaning “the hand of the giant”. The name was later corrupted into Betelgeuse by the Europeans, who also gave it the Bayer designation of Alpha Orionis, meaning the brightest star in Orion.

The first person to record the variability of Betelgeuse was the astronomer John Herschel, who observed it in 1836. He noticed that Betelgeuse changed its brightness by about one magnitude throughout 5.7 to 6.4 years. Later, other astronomers confirmed that Betelgeuse was a variable star, and measured its different cycles and fluctuations.

The first person to measure the size of Betelgeuse was the astronomer Michelson, who used an interferometer in 1920. He found that Betelgeuse had a diameter of about 0.047 arcseconds, which corresponds to about 300 times the diameter of the Sun. Later, other astronomers refined the measurements of Betelgeuse’s size, shape, and surface features, using more advanced techniques and instruments.

The first person to predict the supernova of Betelgeuse was the astronomer Baade, who suggested in 1952 that Betelgeuse was a red supergiant that would end its life in a massive explosion. Later, other astronomers confirmed that Betelgeuse was indeed a supernova candidate, and estimated its mass, age, and distance.

Conclusion

Betelgeuse is a fascinating star that has captivated the imagination of humans for centuries. It is a red supergiant that is very large, bright, and variable. It is also a star that is about to die in a spectacular explosion that will light up the sky. Betelgeuse is a star that we can learn a lot from, and a star that we can enjoy watching. Betelgeuse is a star that might explode soon.