A dark star is a theoretical object compatible with Newtonian mechanics that, due to its large mass, has a surface escape velocity that equals or exceeds the speed of light. Whether light is affected by gravity under Newtonian mechanics is questionable but if it were accelerated the same way as projectiles, any light emitted at the surface of a dark star would be trapped by the star's gravity, rendering it dark, hence the name.
During 1783 geologist John Michell wrote a letter to Henry Cavendish outlining the expected properties of dark stars, published by The Royal Society in their 1784 volume. Michell calculated that when the escape velocity at the surface of a star was equal to or greater than lightspeed, the generated light would be gravitationally trapped, so that the star would not be visible to a distant astronomer.
This assumes that light is influenced by gravity in the same way as massive objects.
Michell's idea for calculating the number of such "invisible" stars anticipated 20th century astronomers' work: he suggested that since a certain proportion of double-star systems might be expected to contain at least one "dark" star, we could search for and catalogue as many double-star systems as possible, and identify cases where only a single circling star was visible. This would then provide a statistical baseline for calculating the amount of other unseen stellar matter that might exist in addition to the visible stars.
Dark Star or Darkstar may refer to:
James T. Struck BA, BS, AA, MLIS argued for Dark Stars as a type of star that generates no or insignicant light even with heat production. He argued for these new stars like purple stars (which were observed historically), green stars (which can be seen) and low energy stars.
A dark star is a type of star that may have existed early in the universe before conventional stars were able to form. The stars would be composed mostly of normal matter, like modern stars, but a high concentration of neutralino dark matter within them would generate heat via annihilation reactions between the dark-matter particles. This heat would prevent such stars from collapsing into the relatively compact sizes of modern stars and therefore prevent nuclear fusion among the normal matter atoms from being initiated.
Under this model, a dark star is predicted to be an enormous cloud of hydrogen and helium ranging between 4 and 2000 astronomical units in diameter and with a surface temperature low enough that the emitted radiation would be invisible to the naked eye.
In the unlikely event that dark stars have endured to the modern era, they could be detectable by their emissions of gamma rays, neutrinos, and antimatter and would be associated with clouds of cold molecular hydrogen gas that normally wouldn’t harbor such energetic particles.
Dark Star is a brewery in currently located in Partridge Green, in the county of West Sussex, England.
Dark Star was originally the name of a porter developed by Rob Jones when he was employed by the Pitfield Brewery. The name comes from the Grateful Dead song Dark Star. It was highly successful, being voted Champion Beer of Britain in 1987. He took the recipe with him when he moved to the brewery based at the Evening Star. The beer itself is now known as Dark Star Original.
The Dark Star Brewery Company started, in 1994, as a small plant squeezed into a corner of the cellar of The Evening Star Pub, in Brighton. The company was founded by entrepreneur Peter Halliday, publican Peter Skinner, and brewer Rob Jones. At that time it was known as Skinner's brewery, but there was another Skinner's brewery in Cornwall, so the name was changed to Dark Star, after Jones's successful recipe for porter.(The resemblance between the names "Dark Star" and "Evening Star" is coincidental). It soon became apparent before long that the brewery could not keep up with the growing demand from the Evening Star’s drinkers, let alone the demand for its beers from other pubs.