The Galaxy's Largest Diamond

Found on Harvard-Smithsonian Center for Astrophysics on Friday, 13 February 2004
Browse Astronomy

When choosing a Valentine's Day gift for a wife or girlfriend, you can't go wrong with diamonds. If you really want to impress your favorite lady this Valentine's Day, get her the galaxy's largest diamond. But you'd better carry a deep wallet, because this 10 billion trillion trillion carat monster has a cost that's literally astronomical!

The newly discovered cosmic diamond is a chunk of crystallized carbon 50 light-years from the Earth in the constellation Centaurus. (A light-year is the distance light travels in a year, or about 6 trillion miles.) It is 2,500 miles across and weighs 5 million trillion trillion pounds, which translates to approximately 10 billion trillion trillion carats, or a one followed by 34 zeros.

The huge cosmic gem (technically known as BPM 37093) is actually a crystallized white dwarf. A white dwarf is the hot core of a star, left over after the star uses up its nuclear fuel and dies. It is made mostly of carbon and is coated by a thin layer of hydrogen and helium gases.

Now that would really be a gift. But then, what could you do with it? You cannot wear it as a ring or necklace. I don't even want to start thinking about the price...