Contrary to popular belief, stars like our sun are not infinite. They don’t live forever. Instead, they go through various life cycles. Once it reaches its final stage, it’s referred to as a White Dwarf. To better understand what a White Dwarf is, you need to get a good grasp of how a star changes throughout its life.
When A Star Is Born
Stars are first created when clouds of dust and gas are affected by gravity. The forces of gravity cause the elements to group together. As this happens, even more gases and dust are drawn in. It’s a snowball effect, as the star’s gravitational pull becomes stronger the bigger it gets. Eventually, that star will start to burn. This produces the light that we see. In the case of our solar system’s star, the sun, it’s what produces heat for us to survive on Earth.
Over billions of years, the star will continue to burn using nuclear fuel. Some stars, like our sun, will continue to swell up and become a red giant. Once the star reaches that red giant phase, it’s getting close to the end of its nuclear burning stage. Basically, the outer layers of the star will start to shed and expel materials, creating a planetary nebula. After all of those outer materials are gone, the only thing that’s left behind is the core of the sun. This is the White Dwarf.
White Dwarves get very hot as they are burning off the last of their nuclear fuel. Many White Dwarf stars reach temperatures over 1,000 degrees Kelvin. To put that into perspective, our own star burns at about 5,778 degrees Kelvin. Despite all that power and heat, White Dwarf stars will run out of fuel eventually. Depending on the conditions, most White Dwarves will then cool off over the next billion years or so until they are nothing more than a dark celestial body.
The cool thing about a White Dwarf is that they are incredibly dense. They’re about 200,000 times as dense as Earth. All of the star’s electrons are compacted by very powerful forces of gravity. A White Dwarf is so dense that it reaches the limits of quantum mechanics. The electrons become so tightly compacted that the star is unable to collapse in on itself. It’s held together by the power of gravity, even long after the nuclear fuel has run out.
Scientists believe that White Dwarf stars develop a modest crust. Below that, it’s hypothesized that there’s a crystalline structure of oxygen and carbon atoms. Essentially, it’s a layer of diamond.
While White Dwarfs are the last stage of a star’s life, it doesn’t mean that its the end of the celestial body. Sure, it’s the remnants of a dead star’s core, but the White Dwarf can gain new life elsewhere. It’s not uncommon for White Dwarves to orbit another star or planet, essentially serving as a moon. Sometimes, they can even cause explosions with other orbiting objects and merge with another White Dwarf to create new stars.