Week 16: Big Bang, Galaxies, Black Holes, Chances of Life.

The universe originated from a singularity, a single point in space, in which matter and time expanded outward. Matter came together, as gravity pulled them inward due to the unbalance and imperfection of nature. Most of the matter was hydrogen and as the matter came together in a web-like structure, other elements were formed due to the the density of the mass. Heavier elements, such as helium were formed and as they compressed, nuclear fusion occured and other heavier elements were produced. Iron, oxygen and other elements were formed and are essential to the formation of life. Luckily, by some chance, the early stars in our galaxy exploded in a supernova as they grew old, and those matters and elements were recycled in a nebula of gas that later formed our solar system.
Scientist explains that life occurred due to a miracle. Our solar system happen to have the right material to form life. The sun was the right size to burn for billion of years and for life to evolve. The earth is the right size and contain the right material to form life... iron in the core to have a protective magnetic field. The distance between the earth and sun is perfect. Any inches closer and life would not exist.
Now lets understand black holes. The term black hole is used because light cannot escape the black hole's immense gravity and in general relativity, black holes have infinite density because of its immense gravity, and therefore, stretches the fabric of time and space inward. Black holes are in the center of most galaxies and not everything gets pulled in. There are escape velocity in which an object reaches a terminal point, and escapes the inward-pull. If it was true that black holes "sucks" in everything, then there would be nothing in space. Quasars are new galaxies in which black holes pulls in too much matter and have to force the matter out in a jet-like stream that burns at millions of degree. Sometimes galaxies even collide with one another due to the attraction of the black hole's gravitational pull. Objects near the black holes rotate at a tremendous rate at a couple million of miles an hour and that may include stars, not just gases or other materials.