For thousands of years, astronomers have had trouble with questions about the age, geometry, and size of the universe. Does the universe extend continuously, or does it have an ending point somewhere? Was the universe created at a certain time or was it here from the beginning? In 1929, astronomer Edwin Hubble, made a breakthrough discovery that led to the scientific answers for the questions above; he discovered that the universe is expanding. First, I will briefly explain some of the cosmological theories natural philosophers and astronomers were able to come up with before Hubble established that the universe is not static, but actually expanding. Ancient Greek philosopher Aristotle proposed that the universe was an eternal, static universe …show more content…
In the 1920s, a Belgian priest named Georges Lemaitre introduced the theory that the universe began from a single atom introducing the Big Bang theory. Unfortunately due to the limitations of the laws of science, no one is able to make guesses about the instant the universe was born, but we can look at the period immediately after the universe was created. The earliest we can go back to is 10-43 seconds. The study of these early moments is referred to as quantum cosmology. At 10-43 seconds, the universe was a very small, dense, and hot point. Then from 10-35 to 10-33 it goes through a process called inflation causing a massive expansion of space with energy. After the inflation at 10-6 seconds, the universe is expanding at a slower rate and becomes cooler and less dense. Basic forces such as gravity, strong force, and electromagnetic forces are distinguishable and the universe is filled with electrons, quarks and other particles. As the cosmos is cooling down, the quarks combine together to form into protons and neutrons. Still too hot to form into atoms, charged electrons and protons prevent light from shining thus the universe is a extremely hot fog. Three seconds after the Big Bang, electrons, protons, and neutrons are able to form into atoms of hydrogen and helium. After 10,000 years, energy is in the form of radiation giving faint glows of light across the universe. 300,000 years later, gravity combines hydrogen and helium gas to form the giant clouds that will become galaxies; smaller clumps of gas collapse to form the first star. Around 300 million years after the Big bang, galaxies cluster together under gravity, the first stars formed die and disperse into heavy elements that will turn into new stars and planets. Hubble’s law and his discovery of the expansion of space is cornerstone of the Big Bang theory, however there was a another discovery that helped in proving