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From the January 2025 problem
Our white dwarf Solar will cool for billions upon billions of years, slowly fading away as a darkish, strong carbon-oxygen ball.
In 2019, astronomers introduced they’d discovered direct proof of white dwarfs solidifying into oxygen-carbon crystals, as depicted on this artist’s illustration. After the white dwarf turns into fully frozen, it cools off and fades because it stops producing mild. Credit score: College of Warwick/Mark Garlick
After our Solar turns into a white dwarf and cools fully, what might be left?
Richard LivitskiSeal Seaside, California
Our Solar will develop into a white dwarf in about 7 billion years. At that time, it can now not produce vitality by means of nuclear fusion, having exhausted its gasoline (hydrogen and helium). Similar to the embers of an deserted campfire can solely calm down with time, the white dwarf Solar will regularly develop into dimmer and cooler because it radiates its warmth away into house.
The inside of one of these star is extremely dense. To place this in perspective, a quantity of white dwarf materials equal to a teaspoon would weigh a number of tons! In such a condensed state, charged particles (oxygen and carbon nuclei) work together strongly because of the highly effective electrostatic forces at play. Initially, these charged particles don’t “feel” this drive an excessive amount of as a result of they’re shifting rapidly in all instructions, because of the star’s very excessive temperature.
However because the white dwarf Solar cools, the particles in its inside decelerate. Ultimately, they develop into so sluggish that they’ll’t overcome the electrostatic interactions squeezing them from all sides — they develop into trapped. The inside of the white dwarf Solar will actually develop into a strong carbon-oxygen crystal. This freezing course of, referred to as crystallization, is predicted to start out roughly 3 billion years after our Solar turns into a white dwarf, or about 10 billion years from now.
Since diamonds are a strong type of carbon, it’s typically stated that white dwarfs flip into diamonds. Nevertheless, this isn’t correct — the matter inside a white dwarf may be very completely different from a diamond. The inside of a white dwarf will not be solely a lot denser than something discovered on Earth but additionally a lot hotter, even by the point the star freezes.
As soon as fully frozen, our white dwarf Solar will proceed cooling for billions upon billions of years, slowly fading away as a darkish, strong carbon-oxygen ball.
Simon BlouinCanadian Institute of Theoretical Astrophysics Nationwide Fellow in Astrophysics, College of Victoria, Victoria, British Columbia, Canada
