Monday, February 14, 2011

nomograph, weather satellite&black hole


A nomogram, nomograph, or abac is a graphical calculating device, a two-dimensional diagram designed to allow the approximate graphical computation of a function: it uses a coordinate system other than Cartesian coordinates. Defining alternatively, a nomogram is a (two-dimensionally) plotted function with n parameters, from which, knowing n-1 parameters, the unknown one can be read, or fixing some parameters, the relationship between the unfixed ones can be studied. Like a slide rule, it is a graphical analog computation device; and, like the slide rule, its accuracy is limited by the precision with which physical markings can be drawn, reproduced, viewed, and aligned. Most nomograms are used in applications where an approximate answer is appropriate and useful. Otherwise, the nomogram may be used to check an answer obtained from an exact calculation method.

The slide rule is intended to be a general-purpose device. Nomograms are usually designed to perform a specific calculation, with tables of values effectively built in to the construction of the scales.


The weather satellite is a type of satellite that is primarily used to monitor the weather and climate of the Earth. Satellites can be either polar orbiting, seeing the same swath of the Earth every 12 hours, or geostationary, hovering over the same spot on Earth by orbiting over the equator while moving at the speed of the Earth's rotation.[1] These meteorological satellites, however, see more than clouds and cloud systems. City lights, fires, effects of pollution, auroras, sand and dust storms, snow cover, ice mapping, boundaries of ocean currents, energy flows, etc., and other types of environmental information are collected using weather satellites. Weather satellite images helped in monitoring the volcanic ash cloud from Mount St. Helens and activity from other volcanoes such as Mount Etna.[2] Smoke from fires in the western United States such as Colorado and Utah have also been monitored.

weather satellite using NASA's Chandra X-ray Observatory have found evidence of the youngest black hole  known to exist in our cosmic neighborhood. The 30-year-old black hole provides a unique opportunity to watch this type of object develop from infancy.

Not even light can escape a black hole's grip, but gas falling into a black hole can heat up and become an intense source of X-rays, at temperatures up to 1,000 times hotter than the sun. Astronomers use the Chandra X-Ray Observatory -- a NASA satellite -- to map these X-ray sources and study their properties

Scientists have found evidence that a giant black hole has been jerked around twice, causing its spin axis to point in a different direction from before. This discovery, made with new data from NASA's Chandra X-ray Observatory, might explain several mysterious-looking objects found throughout the Universe.

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