Monday, July 21, 2014

Evolution of the Gray Wolf

Science has shown that all dog breeds derive from the gray wolf. The dog genome is completely sequenced allowing comparisons between dogs and gray wolves or between dog breeds. The genetic underpinnings of artificial selection at a genome-wide level reflect Darwin's ideas that populations contain significant diversity, and that artificial selection can act on that diversity over time to promote the reproduction of certain variants over others to shift average characteristics of a population. The evidence suggests that natural selection acts in essentially the same way as artificial selection favoring the reproduction of certain variants over others are Darwin's parallels between artificial and natural selection. 

Moon causes waves

The gravitational force of attraction between two massive bodies is larger for larger masses and increases as the distance between them decreases. Tides result from the difference in the moon's gravitational force between two opposite sides of the earth. The side nearer to the moon is pulled with greater force than the center of the earth while the side farther from it is pulled with less force. When the centrifugal force, which is equal and opposite of the gravitational force on the center, is subtracted, the result is two forces pulling away from the center. This mostly affects the oceans which are fluid and therefore easily deformed by this tidal effect resulting in two bulges on opposite sides of the earth in line with the moon. 

Friday, July 4, 2014

Evolution of the Sun

Evolution of a star depends on its mass which determines the amount of fuel available and the maximum central temperature attainable for its fusion reaction. Stars lose mass into space as they burn. The Sun releases proton and electrons generating a solar wind. This wind of energetic particles causes the auroras called the northern and southern lights, which are the result of solar flares that intensify the solar wind. As the hydrogen fusion ends, the fate of a star depends on its mass. 

All stars contradict the Aristotelian view of the eternal eighth sphere of the heavens that contains fixed and immutable stars. The Sun is a low mass star with a final stage of helium fusion that starts 5B years from now and will cause the sun luminosity to increase by a factor of 1000. In 1B years a 10% increase will cause water vapor on earth to be lost into space. As the luminosity increases it will cause the oceans to evaporate and scorch the earth. 

As a star gets older it becomes larger, cooler, and redder; increasing its energy output. The hydrogen fusion stag ends and it morphs to a red giant. Stars eight times larger than the Sun or smaller don't have the mass to explode into a supernova. Therefore the Sun will fade away.

There is hundreds of possible nuclear reaction occurring in stars at different stages in their evolution as well as the aftermath of a supernova explosion. These provided the answer to the profound question of the origin of the elements. The oxygen and nitrogen we breathe, the carbon in our bodies, the metals such as aluminum, silver, gold and platinum were all made from stellar processes. Without the life and death of stars the world could not exist, without the source of energy from the Sun, life could not have developed.