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Welcome to the stars page. Here you will find information about our Sun, the stars, novas and quasars.
The Sun
The sun is actually a star of medium size. The distance from the Earth to the sun varies from 91,377,000mi (147,053,000km) at perihelion to 94,537,OOOmi (152,138,OOOkm) at aphelion. This is taken as the astronomical unit ( A. U. ) of distance used for measuring distances within the solar system. A fusion reaction is what "powers" the sun. In this reaction, hydrogen atoms are fused to other hydrogen atoms, making helium. This produces energy. The sun's gravity is almost 28 times that of the Earth. Regions of magnetic activity produce sunspots. They are approximately 1000 K below the average temperature of 6000 K (on the surface). Stars differ widely in mass, size, temperature, and total energy output, or luminosity. More than 90% of all stars have masses between one tenth and fifty times that of the sun. the most luminous stars, known as red giants, are about a million times more powerful than that of the sun. At the opposite extreme, white dwarfs are no larger than the Earth, and neutron stars are only a few kilometers in radius.
A Star
A star is the same thing as our sun. They vary in size, density and distance form the Earth. The closest star is 4.2 light years away. Stars can be classified by their spectra (Bright Super-giant, Super-giant, Bright Giant, Giant, Sub-Giant, Main Sequence). They are created in a nebula
Supernova and Nova
A nova is when a star suddenly brightens by several thousand times. In a period of days or hours, it can flare to several thousand times its original brightness. The star is thought to be a white dwarf in a two star system (binary). Approximately a dozen novas occur each year in the Milky Way.
A supernova is more explosive and destructive than the nova. It occurs when the nuclear fusion reaction that "powers" the star is insufficient to overcome the "weight" of the star. The resulting explosion can temporarily outshine the galaxy. Supernovas contribute to the formation of new stars by adding material.
A Quasar
A quasar is one 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. Quasars were discovered as the visible counterparts of certain discrete celestial sources of radio waves. Although their visible light is faint, the quasars are optically brighter than the galaxies with which radio sources had been identified before 1963.Before the spectra were studied carefully, it was believed that quasars were stars in our galaxy. However, the lines in their spectra imply that they are receding from the Milky Way with speeds as great as 95% of the speed of light (see red shift). To account for their brilliant light, astronomers believed that quasars are supermassive black holes in galactic nuclei, releasing energy by the accretion of matter through a rotating viscous disk.
