The third coin in the series "Space the Final Frontier".  The coin was struck from 3 ounces of pure silver. A special "black proof" stamp created the perfect base for the colourful image of the Milky Way. The high relief additionally brings the view of the galaxy to life. Limited edition - only 333 pieces worldwide.  A black hole is a region of space-time which, due to the influence of gravity, nothing - including light and information - can leave. According to the General Theory of Relativity, it requires the accumulation of a sufficiently large mass in a sufficiently small volume in order to form. The black hole is surrounded by a mathematically defined surface called the event horizon, which marks the boundary of no return. It is called "black" because it completely absorbs light hitting the horizon, reflecting nothing.