Definition of Quasar
QUASAR
One of a class of blue celestial objects having the appearance of stars when viewed through a telescope and currently believed to be the most distant and most luminous objects in the universe; the name is shortened from quasi-stellar radio source (QSR). Quasars were discovered as the visible counterparts of certain discrete celestial sources of radio waves (see radio astronomy). Similar star like objects that do not emit radio waves were subsequently discovered and named quasi-stellar objects (QSOs). Although their visible light is faint, the quasars are optically brighter than the galaxies with which radio sources had been identified before 1963. Before their spectra were studied carefully, it was believed that the quasars were stars in our galaxy. However, the lines in their spectra have enormous red shifts that seem to imply that they are receding from the Milky Way with speeds as great as 95% of the speed of light. Only shifts toward the red end of the spectrum have been observed for quasars; blue-shifted ones that would indicate a quasar approaching our galaxy have not yet been found. If quasars were simply objects being ejected from nearby galaxies at high speeds, and not the distant objects they appear to be, then some would have blue shifts. If Hubble's law for the expansion of the universe is extrapolated to include the quasars, they would be many billion light-years away and consequently as luminous intrinsically as 1,000 galaxies combined. To account for such brilliant light, astronomers believe that quasars are supermassive black holes in galactic nuclei, releasing energy by the accretion of matter through a rotating viscous disk (see cosmology).
Wednesday, September 22, 2010
Where does the name "MILKY WAY" came from?
On a clear moonless night,far from city lights,you can see a plate band of light spangle with stars stretching across the sky.The Ancient Hindus though this shimmering river of life in the heavens was the source of the sacred river Ganges. To the Ancient Greeks this dim celestial glow looked like milk split across the night sky, and so they called it the milky way. In the 17th Century, Galileo showed that the milky way is millions of stars too dim to be seen as individual points of lights. Now, in the 20th Century we know that these stars, along with our sun, form a huge, slowly revolving disk-our galaxy. The word "galaxy" itself comes from the ancient Greeks and their word for "milk"-galactos. Thus "milky way" is both the name of the bond of life across the night sky and also the name of our galaxy.
On a clear moonless night,far from city lights,you can see a plate band of light spangle with stars stretching across the sky.The Ancient Hindus though this shimmering river of life in the heavens was the source of the sacred river Ganges. To the Ancient Greeks this dim celestial glow looked like milk split across the night sky, and so they called it the milky way. In the 17th Century, Galileo showed that the milky way is millions of stars too dim to be seen as individual points of lights. Now, in the 20th Century we know that these stars, along with our sun, form a huge, slowly revolving disk-our galaxy. The word "galaxy" itself comes from the ancient Greeks and their word for "milk"-galactos. Thus "milky way" is both the name of the bond of life across the night sky and also the name of our galaxy.
Friday, September 10, 2010
Who among the contributors, has a major-major impact to you?Explain
-Now a days, people discover a lot of things which helps the individual to do certain things in easiest and fastest way. One of the contributor that has a great impact to me is none other than CHARLES BABAGES who discover the computer on a year 1980. Computer is a programmable electronic device that can store, retrieve, and process data. Usually computer show or gives us detailed data or information to have an accurate meaning or information according to our needs.
Bakit sa tingin n yo nag-boom ang science sa RENAISSANCE PERIOD?
-I think the reason behind,it is because the scientist began to think about more complex invention or discoveries in which people can widely used. And also I think they want to widen their horizon that leads to do scientific studies of certain things. Scientist in this period has an opportunity to share their ideas to other scientist compare with the other period they nomadic lifestyle affects their communication.
-Now a days, people discover a lot of things which helps the individual to do certain things in easiest and fastest way. One of the contributor that has a great impact to me is none other than CHARLES BABAGES who discover the computer on a year 1980. Computer is a programmable electronic device that can store, retrieve, and process data. Usually computer show or gives us detailed data or information to have an accurate meaning or information according to our needs.
Bakit sa tingin n yo nag-boom ang science sa RENAISSANCE PERIOD?
-I think the reason behind,it is because the scientist began to think about more complex invention or discoveries in which people can widely used. And also I think they want to widen their horizon that leads to do scientific studies of certain things. Scientist in this period has an opportunity to share their ideas to other scientist compare with the other period they nomadic lifestyle affects their communication.
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