The Fate of a Dying Star

Tala Momin
Jul 16
4 min read

Education for All

By: Nouf Aldamer _______

A star lives a long, beautiful life, illuminating our night sky and carrying with it countless stories from cultures around the world. But at the end of its long, tiring life, after shining brightly for countless years, never once dimming its twinkle, it is granted one final flare. It gets a chance to flourish one last time, and its fate is written in the weight it carried all its life. What happens next is one of the universe’s most fascinating transformations, so come with me as I walk you through the different types of stars and how they end up.

Low-mass Stars:

Low-mass stars are stars between 0.6-1.4 solar masses. A solar mass is the mass of our Sun, and scientists use it to easily compare how big or heavy other stars are (1 solar mass = 1 sun). Low-mass stars are usually less than about 8 times the mass of the Sun, which means that the Sun is a typical low-mass star. These stars spend most of their lifetime fusing hydrogen into helium, and when the hydrogen runs out, the star gets kind of dramatic and in a fit of rage it swells up into a red giant and throws off its outer layer into space. What's left is a white dwarf that’s so dense, one tablespoon of white dwarf material equals about five tons!

White dwarfs are small, about as small as the Earth, but with a hundred times the weight of Earth. Think of it like that saying, “would you rather have one kilogram of feathers, or one kilogram of bricks”– a big star being the feathers, and a white dwarf being the bricks; they all weigh the same of course, one kilogram, but one is big and has a lot of room for the weight to distribute, and the other is small, and doesn't have much room for the weight to distribute– which makes it dense.

White dwarfs don’t produce new energy; instead, they use the remaining energy they had as a star to glow. But when the energy runs out, over trillions of years, it cools down and loses all light. It’s scientifically called a black dwarf at that stage, but only in theory, because the universe isn’t old enough for one to form.

Medium to high-mass stars:

These are classified as any star that is between 8-20 solar masses, and these stars burn through fuel way faster than smaller stars because they require more energy to glow. That's because they are heavier and their core’s pressure and temperature are much higher. These stars die fast; they only live a few million years, and in space that's very little! You could say they ‘live fast and die young’. Once the core collapses in on itself, the star doesn't just fade away– oh no, the outer layers blast off in a huge dramatic supernova explosion, it leaves with a bang so big it shakes the galaxy! It’s the star’s final act, and it makes sure everyone notices. And if the leftover core isn’t too massive, that bang leaves behind a tiny but mighty object: a neutron star, space’s densest drama queen.

Extremely massive stars:

When a star is really huge, like 20+ solar masses– it doesn't just leave a small dense core. It makes all the other types of stars look foolish compared to it. The core collapses so much that it dies as a black hole. It becomes a region in space with so much gravity, not even light can escape, like a Jedi turned Sith.

Black holes are the universe’s biggest mystery, no light escapes them, no signal comes out, and yet… They have scientists’ hooked. In 2019, Dr. Katie Bouman helped lead the team that captured the first ever image of a black hole’s shadow. A glowing ring of light fifty-five million light years away, using the Event Horizon Telescope (aka the coolest telescope ever!).

And before that, in 2015, Dr. Kip Thorne, Rainer Weiss, and Barry Barish detected gravitational waves from two black holes merging for the first time using LIGO. That discovery won them the 2017 Nobel Prize in Physics.

Black holes are a whole huge topic all on their own, and a discovery in the way they function takes years– even decades to find. They don't just break the rules of physics, they rewrite them, forever confusing people for all of time.

So, whether a star becomes a calm white dwarf, a spinning neutron star, or a scary black hole depends all on one thing: its mass. The bigger it is, the faster it burns, the louder it ends, and the wider its legacy. Stars really do go out with style; some with sparkle, some with a bang, and some collapse into the universe's biggest mystery.

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