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  2. Black hole - Wikipedia

    en.wikipedia.org/wiki/Black_hole

    A black hole with the mass of a car would have a diameter of about 10 −24 m and take a nanosecond to evaporate, during which time it would briefly have a luminosity of more than 200 times that of the Sun. Lower-mass black holes are expected to evaporate even faster; for example, a black hole of mass 1 TeV/c 2 would take less than 10 −88 ...

  3. Black hole thermodynamics - Wikipedia

    en.wikipedia.org/wiki/Black_hole_thermodynamics

    In physics, black hole thermodynamics [1] is the area of study that seeks to reconcile the laws of thermodynamics with the existence of black hole event horizons.As the study of the statistical mechanics of black-body radiation led to the development of the theory of quantum mechanics, the effort to understand the statistical mechanics of black holes has had a deep impact upon the ...

  4. Density of air - Wikipedia

    en.wikipedia.org/wiki/Density_of_air

    At IUPAC standard temperature and pressure (0 °C and 100 kPa), dry air has a density of approximately 1.2754 kg/m 3. At 20 °C and 101.325 kPa, dry air has a density of 1.2041 kg/m 3. At 70 °F and 14.696 psi, dry air has a density of 0.074887 lb/ft 3.

  5. Sagittarius A* - Wikipedia

    en.wikipedia.org/wiki/Sagittarius_A*

    Sagittarius A*, abbreviated as Sgr A* (/ ˈ s æ dʒ ˈ eɪ s t ɑːr / SADGE-AY-star [3]), is the supermassive black hole [4] [5] [6] at the Galactic Center of the Milky Way.Viewed from Earth, it is located near the border of the constellations Sagittarius and Scorpius, about 5.6° south of the ecliptic, [7] visually close to the Butterfly Cluster (M6) and Lambda Scorpii.

  6. Schwarzschild radius - Wikipedia

    en.wikipedia.org/wiki/Schwarzschild_radius

    (Supermassive black holes up to 21 billion (2.1 × 10 10) M ☉ have been detected, such as NGC 4889.) [17] Unlike stellar mass black holes, supermassive black holes have comparatively low average densities. (Note that a (non-rotating) black hole is a spherical region in space that surrounds the singularity at its center; it is not the ...

  7. Supermassive black hole - Wikipedia

    en.wikipedia.org/wiki/Supermassive_black_hole

    Some astronomers refer to black holes of greater than 5 billion M ☉ as ultramassive black holes (UMBHs or UBHs), [19] but the term is not broadly used. Possible examples include the black holes at the cores of TON 618 , NGC 6166 , ESO 444-46 and NGC 4889 , [ 20 ] which are among the most massive black holes known.

  8. List of most massive black holes - Wikipedia

    en.wikipedia.org/wiki/List_of_most_massive_black...

    The supermassive black hole at the core of Messier 87, here shown by an image by the Event Horizon Telescope, is among the black holes in this list.. This is an ordered list of the most massive black holes so far discovered (and probable candidates), measured in units of solar masses (M ☉), approximately 2 × 10 30 kilograms.

  9. Energy density - Wikipedia

    en.wikipedia.org/wiki/Energy_density

    A 1 inch tall uranium fuel pellet is equivalent to about 1 ton of coal, 120 gallons of crude oil, or 17,000 cubic feet of natural gas. [15] In light-water reactors , 1 kg of natural uranium – following a corresponding enrichment and used for power generation– is equivalent to the energy content of nearly 10,000 kg of mineral oil or 14,000 ...