A black dwarf is a hypothetical astronomical object: a white dwarf so old that it has cooled down so that it no longer emits significant heat or light. None are expected to exist yet, since the time required for a white dwarf to cool down is calculated to be longer than the current age of the universe. To meet Wikipedias quality standards, this article or section may require cleanup. ... Image of Sirius A and Sirius B taken by the Hubble Space Telescope. ... The age of the universe, according to the Big Bang theory, is defined as the largest possible value of proper time integrated along a time-like curve from the Earth at the present epoch back to the Big Bang. The time that has elapsed on a hypothetical clock which has...

Evolution

A white dwarf star is what remains of a Sun-sized star after it has fused virtually all of its original hydrogen and helium fuel to heavier elements such as carbon, oxygen, and nitrogen and is unable to carry on any further fusion of the byproducts. It then begins to cool down by simple thermal radiation. Image of Sirius A and Sirius B taken by the Hubble Space Telescope. ... The Sun is the star at the center of the Solar System. ... This article is about the astronomical object. ...

Even if black dwarfs did exist, they would be extremely difficult to detect, since by definition they would emit very little radiation (if any), or at most their radiation would be a temperature not much above that of the cosmic microwave background radiation. They may be detectable through their gravitational influence. WMAP image of the CMB anisotropy,Cosmic microwave background radiation(June 2003) The cosmic microwave background radiation (CMB) is a form of electromagnetic radiation that fills the whole of the universe. ... Gravity is a force of attraction that acts between bodies that have mass. ...

Both black dwarfs and white dwarfs are degenerate dwarfs. A Degenerate dwarf is type of star, an alternative name for what is commonly called a White dwarf (see this reference for a more complete article). ...

Black dwarfs should not be confused with the unrelated brown dwarfs, which are formed when gas contracts to form a star, but does not possess enough mass to initiate and sustain hydrogen nuclear fusion. "Brown dwarfs" were at times called "black dwarfs" in the 1960s. Neither should black dwarfs be confused with black holes or neutron stars, as neither is the result of the cooling of a white dwarf. This brown dwarf (smaller object) orbits the star Gliese 229, which is located in the constellation Lepus about 19 light years from Earth. ... This article is about the chemistry of hydrogen. ... The deuterium-tritium (D-T) fusion reaction is considered the most promising for producing fusion power. ... The 1960s decade refers to the years from January 1, 1960 to December 31, 1969, inclusive. ... A black hole is an object predicted by general relativity,[1] with a gravitational field so powerful that even electromagnetic radiation (such as light) cannot escape its pull. ... A neutron star is one of the few possible endpoints of stellar evolution. ...

A white dwarf is the leftovers from a star that has burned out of fuel.

References

• Richmond, Michael. Late stages of evolution for low-mass stars (English). Rochester Institute of Technology. Retrieved on 2006-08-04.