In the depths of our Milky Way galaxy, there exists a celestial gem that is not just a metaphorical diamond but quite literally a cosmic jewel on a grand scale. This diamond in the sky is actually a crystallized white dwarf star, often referred to as BPM 37093, located about 50 light-years away in the constellation Centaurus. It has earned the nickname 'Lucy', after The Beatles’ song "Lucy in the Sky with Diamonds." What makes Lucy so fascinating is not just its composition but its size—it's larger than Earth and weighs approximately 5 million trillion trillion pounds.
White dwarfs like Lucy are the remnants of stars that have burned through their nuclear fuel. As these stars cool over billions of years, their carbon and oxygen nuclei can crystallize, forming a giant diamond. More than 90% of all stars will eventually end up as white dwarfs, but not all will turn into diamonds.
Lucy is exceptionally significant because scientists believe that it consists mostly of crystalline carbon. Observations and studies suggest that up to 90% of its mass could be crystalline, making Lucy the largest diamond ever discovered. This structure forms under the immense pressure and temperature inside the white dwarf, a process not unlike how diamonds are formed on Earth—albeit on a vastly more colossal scale.
The discovery and study of Lucy provide a unique window into understanding the life cycles of stars, particularly those transitioning into white dwarfs. It also offers insights into the cosmic distribution of carbon, a fundamental building block of life. Moreover, as the crystallization process releases latent heat, it can tell astrophysicists a great deal about the cooling rates and the thermal history of white dwarfs.
The idea of a giant diamond floating in space captures the imagination and stretches our understanding of where and how complex elements can form throughout the universe. While the massive cosmic diamond is not something we could ever mine or harness for practical use, its mere existence is a vivid reminder of the universe’s beauty and mysteries. As scientists continue to explore these remnants of stars, each discovery like Lucy helps to piece together the broader cosmic puzzle of our galaxy's intricate and magnificent lifecycle.
