The Cosmic Events discussed here are a few of those major events that shape the universe…”the movers and shakers” of the universe. They are not the comets that occasionally pass our way, nor the asteroids that threaten our life…although those are the issues that have the greatest direct impact on us. The ‘movers and shakers” of this universe are those events which define the path for the development of this universe.
The following major events are discussed herein. Click on the hyperlink to learn more.
- The Big Bang – the start of the universe.
- Star life – the initial formation of stars to the death of stars, which allowed many other events to take place, like the formation of planets and Black Holes.
- Quasars – Black Holes
- and finally, Colliding Galaxies.
Of course there are many other cosmic events which have important effects on the universe but the above seem to have a common thread between them which fundamentally defines how our universe has developed.
Some background physics (you can skip this if you like)
It is interesting to note that there are three fundamental concepts from physics that I like to think of as instrumental to the development of the universe as we know it….gravity, conservation of angular momentum, and temperature:
Gravity. We are well aware of the effects of gravity. It is the universal attraction between all objects…always has been, always will be (except, of course, for love). The force of gravity exists between all objects and is proportional to the objects mass….the more mass the higher the force of gravity. In the early stages of the formation of the universe gravity was very weak. As particles begin to form there was little mass and therefore little gravitational force to attract them. But there was some force, and this force, as small as it was, begin to attrack small particles until the mass accumulated, gravity became stronger, and things begin to come together. The process was slow and took millions of years. Of course the first particles were hydrogen and as these came together in sufficient numbers, stars were born and so the process for formation of the elements began. See Life of a Star.
Conservation of Angular Momentum. You may have noticed that everything in the universe is rotating…Moons around planets, planets around suns, suns around galaxies, galaxies around other galaxies. Even asteroids and comets rotate around suns. How does that happen? Conservation of angular momentum! …..in the beginning, when gravity first had that little tug of one particle to another, there was a slight hint of rotation or a slight differential of the velocity component perpendicular to the line of gravity. No matter how slight it was, there was that small, insignificant velocity component. As more and more particles and, later, clumps of matter were attracted the resultant momentum had a definite angular component. That component of angular momentum is conserved as the particles are drawn closer through the action of gravitational force…as the distance gets smaller, the rotation gets faster. Remember the well known example of the spinning ice skater….begin a spin with outstretched arms and the rotation will increase to a blazing fast spin as the arms and legs are brought into the body. From this law of physics we end up today with a host of spinning structures….and it is because of that we don’t go flying off into oblivion, or, crashing into the sun.
Temperature. It is also interesting to note that temperature plays an essential role in the occurrence of these Cosmic events. Consider this sequence of events:
At the moment of the Big Bang the temperature of the universe was large, 10 Octillion°C ! After 3 minutes it had dropped to a billion degrees, and has been decreasing ever since. From the moment of the Big Bang the universe has been expanding and, in this expansion, it has been cooling. Currently it is -270°C (or 3K, just 3 degrees Celsius above absolute zero)…. very cold. How do we know this? The initial temperature was calculated, based on theoretical ideas of what happened at the time. The current temperature has actually been measured and confirms the temperature predicted, based on the theories for the initial temperature.
In any event, the Big Bang occurred at some ungodly high temperature, as it cooled it allowed atoms to form, and, as it cooled further, it allowed gravity to take effect and stars to form.
The subsequent death of massive stars results in the formation of Black Holes. Black Holes, while consuming huge quantities of material, oddly enough pump enormous amounts of energy into the surrounding space and, by so doing. raise the temperature of local gas clouds millions of degrees.
Since star formation requires cool gas clouds for condensation of the gas as well as to allow gravity to exert its influence, this heating of the gas clouds by Black Holes effectively stops, or a least slows down, the formation of stars in the vicinity.
All of this is dependent on the temperature of the material.