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Niue Island SUPERMASSIVE BLACK HOLE $2 Silver Coin 2017 Antique and Proof finish Concave depth 1 oz


Product Code: MA-S-HOL-17-1
Availability: IN STOCK
Name of series
Unique Shapes > CLICK TO VIEW
Metal Silver
Mintage 999
Fineness (% purity) 99.9%
Content (Troy OZ) 1
Denomination (NZD) $2
Weight (g) 31.10
Diameter (mm) 38.61
Year of Issue 2017
Country Niue Island
Edge Reeded
Quality Antique and Proof finishes (selective Proof finish on swirling space debris)
Exterior Decoration Concave depth; Selective Proof finish on swirling space debris
Package Yes
Certificate of Authenticity Yes
Serial number Yes
If Your order has had a customs charge applied in Your country we will refund You a VAT or TAX
Free Shipping Local & International
✔ One of the unexplored topic of the space - Black Hole
✔ Selective Proof finish on swirling space debris
Conсave depth
Antique and Proof finishes
✔ Pure 99.9% silver 1 ounce
✔ Mintage 999 coins in the world
✔ Special box
Legal tender of Niue Island (New Zealand Dollar)
Certificate of Authenticity

Donald Lynden-Bell and Martin Rees hypothesized in 1971 that the center of the Milky Way galaxy would contain a supermassive black hole. Sagittarius A* was discovered and named on February 13 and 15, 1974, by astronomers Bruce Balick and Robert Brown using the baseline interferometer of the National Radio Astronomy Observatory. They discovered a radio source that emits synchrotron radiation; it was found to be dense and immobile because of its gravitation. This was, therefore, the first indication that a supermassive black hole exists in the center of the Milky Way.
A supermassive black hole (SMBH) is the largest type of black hole, on the order of hundreds of thousands to billions of solar masses (M☉), and is found in the centre of almost all currently known massive galaxies. In the case of the Milky Way, the SMBH corresponds with the location of Sagittarius A*.
Supermassive black holes have properties that distinguish them from lower-mass classifications. First, the average density of a SMBH (defined as the mass of the black hole divided by the volume within its Schwarzschild radius) can be less than the density of water in the case of some SMBHs. This is because the Schwarzschild radius is directly proportional to mass, while density is inversely proportional to the volume. Since the volume of a spherical object (such as the event horizon of a non-rotating black hole) is directly proportional to the cube of the radius, the minimum density of a black hole is inversely proportional to the square of the mass, and thus higher mass black holes have lower average density. In addition, the tidal forces in the vicinity of the event horizon are significantly weaker for massive black holes. As with density, the tidal force on a body at the event horizon is inversely proportional to the square of the mass: a person on the surface of the Earth and one at the event horizon of a 10 million M☉ black hole experience about the same tidal force between their head and feet. Unlike with stellar mass black holes, one would not experience significant tidal force until very deep into the black hole.
Your benefits:
• Extremely high international collectible demand
• Highly appreciated in an investing in collectible low mintage coins
• Present this beautiful coin to your loved one for any occasions or a great business gift
月亮島超大質量黑洞$ 2銀幣2017古董和證明完成凸深1盎司


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