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Black hole

Black hole
A black hole is defined as a region of spacetime from which gravity prevents anything, including light, from escaping.[1] The theory of general relativity predicts that a sufficiently compact mass will deform spacetime to form a black hole.[2] Around a black hole, there is a mathematically defined surface called an event horizon that marks the point of no return. The hole is called "black" because it absorbs all the light that hits the horizon, reflecting nothing, just like a perfect black body in thermodynamics.[3][4] Quantum field theory in curved spacetime predicts that event horizons emit radiation like a black body with a finite temperature. This temperature is inversely proportional to the mass of the black hole, making it difficult to observe this radiation for black holes of stellar mass or greater. Objects whose gravity fields are too strong for light to escape were first considered in the 18th century by John Michell and Pierre-Simon Laplace. History General relativity

http://en.wikipedia.org/wiki/Black_hole

Related:  outer space

Interstellar nitrogen monohydride Nitrogen monohydride (NH) is a simple compound that has been detected in interstellar space. History[edit] One of the earliest papers on the NH molecule was in 1976 by Richard M. Crutcher and William D. Watson. They were still trying to pinpoint the absorption line for NH. Apollo 11 Broadcast on live TV to a world-wide audience, Armstrong stepped onto the lunar surface and described the event as "one small step for [a] man, one giant leap for mankind." Apollo 11 effectively ended the Space Race and fulfilled a national goal proposed in 1961 by the late U.S. President John F. Kennedy in a speech before the U.S. Congress: "before this decade is out, of landing a man on the Moon and returning him safely to the Earth.

Galaxy Galaxies contain varying numbers of planets, star systems, star clusters and types of interstellar clouds. In between these objects is a sparse interstellar medium of gas, dust, and cosmic rays. Supermassive black holes reside at the center of most galaxies. Aurora (astronomy) Images of the aurora australis and aurora borealis from around the world, including those with rarer red and blue lights Overview[edit] Auroras are classified as diffuse and discrete.

Inflation (Wikipedia) In physical cosmology, cosmic inflation, cosmological inflation, or just inflation is a theory of exponential expansion of space in the early universe. The inflationary epoch lasted from 10−36 seconds after the Big Bang to sometime between 10−33 and 10−32 seconds. Following the inflationary period, the Universe continues to expand, but at a less rapid rate.[1] Astrophysics Astrophysics (from Greek astron, ἄστρον "star", and physis, φύσις "nature") is the branch of astronomy that deals with the physics of the universe, especially with "the nature of the heavenly bodies, rather than their positions or motions in space."[1][2] Among the objects studied are galaxies, stars, planets, extrasolar planets, the interstellar medium and the cosmic microwave background.[3][4] Their emissions are examined across all parts of the electromagnetic spectrum, and the properties examined include luminosity, density, temperature, and chemical composition. Because astrophysics is a very broad subject, astrophysicists typically apply many disciplines of physics, including mechanics, electromagnetism, statistical mechanics, thermodynamics, quantum mechanics, relativity, nuclear and particle physics, and atomic and molecular physics.

Moon landing Clickable imagemap of the locations of all successful soft landings on the Moon to date. Dates are landing dates in UTC. Still frame from a video transmission, taken moments before Neil Armstrong became the first human to step onto the surface of the Moon, at 02:56 UTC on 21 July 1969. An estimated 500 million people worldwide watched this event, the largest television audience for a live broadcast at that time.[1][2] Luna 2, the first object made on Earth to reach the surface of the Moon.

Nebula Portion of the Carina nebula A nebula (from Latin: "cloud";[1] pl. nebulae or nebulæ, with ligature, or nebulas) is an interstellar cloud of dust, hydrogen, helium and other ionized gases. Originally, nebula was a name for any diffuse astronomical object, including galaxies beyond the Milky Way. The Andromeda Galaxy, for instance, was referred to as the Andromeda Nebula (and spiral galaxies in general as "spiral nebulae") before the true nature of galaxies was confirmed in the early 20th century by Vesto Slipher, Edwin Hubble and others. Nebulae are often star-forming regions, such as in the Eagle Nebula. This nebula is depicted in one of NASA's most famous images, the "Pillars of Creation".

Related:  Black HoleSpacespace