Definitions for black dwarf
black dwarf

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1. black dwarfnoun

   a hypothesized white dwarf that has cooled down and no longer emits visible light

WikipediaRate this definition:0.0 / 0 votes

1. Black dwarf

   A black dwarf is a theoretical stellar remnant, specifically a white dwarf that has cooled sufficiently to no longer emit significant heat or light. Because the time required for a white dwarf to reach this state is calculated to be longer than the current age of the universe (13.8 billion years), no black dwarfs are expected to exist in the universe at the present time. The temperature of the coolest white dwarfs is one observational limit on the universe's age.The name "black dwarf" has also been applied to hypothetical late-stage cooled brown dwarfs – substellar objects with insufficient mass (less than approximately 0.07 M☉) to maintain hydrogen-burning nuclear fusion.

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1. Black dwarf

   A black dwarf is a hypothetical stellar remnant, created when a white dwarf becomes sufficiently cool enough to no longer emit significant heat or light. Since the time required for a white dwarf to reach this state is calculated to be longer than the current age of the universe, no black dwarfs are expected to exist in the universe yet, and the temperature of the coolest white dwarfs is one observational limit on the age of the universe. A white dwarf is what remains of a main sequence star of low or medium mass, after it has either expelled or fused all the elements which it has sufficient temperature to fuse. What is left is then a dense ball of electron-degenerate matter which cools slowly by thermal radiation, eventually becoming a black dwarf. If black dwarfs were to exist, they would be extremely difficult to detect, since, by definition, they would emit very little radiation. They would, however be detectable through their gravitational influence. Since the far-future evolution of white dwarfs depends on physical questions, such as the nature of dark matter and the possibility and rate of proton decay, which are poorly understood, it is not known precisely how long it will take white dwarfs to cool to blackness, § IIIE, IVA. Barrow and Tipler estimate that it would take 1015 years for a white dwarf to cool to 5 K; however, if weakly interacting massive particles exist, it is possible that interactions with these particles will keep some white dwarfs much warmer than this for approximately 1025 years, § IIIE. If protons are not stable, white dwarfs will also be kept warm by energy released from proton decay. For a hypothetical proton lifetime of 1037 years, Adams and Laughlin calculate that proton decay will raise the effective surface temperature of an old one-solar mass white dwarf to approximately 0.06 K. Although cold, this is thought to be hotter than the temperature that the cosmic background radiation will have 1037 years in the future, §IVB.

How to pronounce black dwarf?

1. Alex

   US English

   David

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   Mark

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   Daniel

   British

   Libby

   British

   Mia

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   Karen

   Australian

   Hayley

   Australian

   Natasha

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   Indian

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   Neerja

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   Oliver

   British

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   South African

How to say black dwarf in sign language?

Numerology

1. Chaldean Numerology

   The numerical value of black dwarf in Chaldean Numerology is: 5

2. Pythagorean Numerology

   The numerical value of black dwarf in Pythagorean Numerology is: 9

References

1. ^ Wiktionary
   https://en.wiktionary.org/wiki/Black_Dwarf
2. ^ Wikipedia
   https://en.wikipedia.org/wiki/Black_Dwarf
3. ^ Wikidata
   https://www.wikidata.org/w/index.php?search=black dwarf