The Big Bang was an explosion of energy. Energy and matter can be converted into the other form and are interchangeable under certain conditions. The Big Bang was an explosion of energy. Soon after the explosion conditions were such that the energy was able to transform into matter. Some energy remained and can be detected in the universe today. The evidence of the Big Bang Theory are, we are reasonably certain that the universe had a beginning, Galaxies appear to be moving away from us at speeds proportional to their distance, If the universe was initially very, very hot as the Big Bang suggests, we should be able to find some remnant of this heat, The abundance of the "light elements" Hydrogen and Helium found in the observable universe are thought to support the Big Bang model of origins. Edwin Hubble was born on November 20, 1889. He graduated from the University of Chicago and served in WWI before settling down to lead research in the field of astrophysics at Mount Wilson Observatory in California. Hubble's revolutionary work includes finding a constant relationship between galaxies' redshift and distance, which helped to eventually prove that the universe is expanding. Additionally, a classification system that he created for galaxies has been used by other researchers for decades.
The heliocentric model is a theory that places the Sun as the center of the Universe, and the planets orbiting around it. The heliocentric model replaced geocentrism, which is the belief that the Earth is the center of the universe. The geocentric model was the prevailing theory in Ancient Greece, throughout Europe, and other parts of the world for centuries. It was not until the 16th century that the heliocentric model began to gain popularity because technology progressed enough to gain more evidence in its favor. Although heliocentrism did not gain popularity until the 1500′s, the idea had existed for centuries throughout the world. The geocentric system was the first model of our solar system-dating back to the times of Aristotle and is best known as the Ptolemaic system after the Greek philosopher Ptolemy. This model predicted an earth-centered system hence geocentric and it was the most favorable until about the late 15 hundreds if my memory is serving me well. however some astronomers were not concurring to the geocentric model, in the light of that a guy known as Nicolaus Copernicus devised a secret(this was against the teachings of the church and it was death punishable) heliocentric system with the sun at the center of our solar system. Planets, Comets, Meteors, and Asteroids are all similar and different in many ways. The similarities are all of them orbit Sun and so members of Solar system. All planets are similar in that they have spherical bodies. They lie more or less in the same Ecliptic plane with very a little inclination. Inner planets are small, rocky and with thin atmospheres. Outer planets are gas giants with no evidence supplied by them about the possibility of an inner solid core unlike the 'crusty' inner planets. Comets are minute in comparison. Also their composition of ice and hydrocarbons differs from the others. The hydrocarbons and water vapor impart them that distinct luminous tails that distinguish them from the others. Their very small masses and sizes subject them to gravitational pulls shaping the orbits in weird forms. There are many Mars grazers and Jupiter grazers. Even some Earth grazers are there. Much of the inner planetary space is dusty with grains of sand of all types even to the size of boulders and kilometer-across sizes. All these can be called Meteors. But only those that are sucked into Earth's gravitational field, passing through its 300 km thick atmosphere to get burnt to cinders on friction with the atmospheric gases, are called Meteors. The ashes get dropped as dust settling on the ground and cinders if found are called Meteorites.