Back to category: Science Limited version - please login or register to view the entire paper. Astronomy Stars A star is a luminous globe of gas consisting of mainly hydrogen and helium which produces its own heat by nuclear reaction, stars shine for many billions of years although they have been found to have changed in appearance and size. We can see stars from earth because they are bright and glowing, it is a luminous globe of gas, the temperature rises as dust grains radiate much of the heat, but as it grows denser less of the heat generated can escape and it warms up. When the star is about 10 million degrees Celsius the temperature is very hot, high enough for a nuclear reaction to begin, vast amounts of energy are released, contraction stops and the star shines. Constellations As seen from the Earth, all the historic planets are conspicuous naked-eye objects moving in looped ... Posted by: Gina Allred Limited version - please login or register to view the entire paper. |
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