What happens when a star dies?
Fifty light years — that’s about 300,000,000,000,000 (300 quadrillion) miles — away from Earth is Lucy, a former star whose proverbial bulb has burned out. And Lucy’s core has turned into a diamond. In this case, the diamond is huge — the largest in the galaxy. At 10 billion trillion trillion carats — 1 followed by 34 zeroes! — it’s, well, huge beyond imagination. The largest terrestrial diamond, the Golden Jubilee Diamond, is about 500 carats — a 5, followed by two lonely zeroes.
How’d this happen?
When a star consumes all of its fuel, it burns out, leaving behind a white dwarf — a hot, crystalizing core. For years, scientists have believed that the core, made mostly of carbon, turns into a diamond, but we have had no evidence supporting that thesis. That all changed in 2004, when astronomers were able to use gong-like pulsations emanating from Lucy to determine that its core was a really big diamond and developed the model pictured above. (Scientists use a similar method terrestrially, measuring the Earth’s seismic activity to answer questions about the makeup of the Earth’s core.)
And why “Lucy”? The white dwarf’s official name is BPM 37038 — a nomenclature without meaning to lay people. Lucy received her informal name upon the discovery of her diamond core — as a tribute to the Beatles.
From the Archives: Pale Blue Dot: There’s a lot of stuff out there, and very very little of it is us.