The End of the Universe
There are many theories predicting how the universe will end. These theories are based on one four basic principles. The first principle being that the universe continues in an endless cycle. The next is that the universe will stay at its current size. The third is the universe will continue to expand endlessly. The final principle, states that the universe will collapse on itself.
The first theory is based on the fact that the universe is oscillating. The universe currently is expanding outward. This expansion is being slowed down by gravity. While this is happening almost all of the stars in the universe will have died and become cold. At this time the gravitational pull will stop the expansion of the universe. The universe will then reverse its direction and begin to collapse on it? self. When it collapses the gravitational pull will become stronger until all the mass of the universe collapses into a black hole. The black hole will produce singularity similar to the one that produced the big bang. The singularity will then explode and produce another big bang restarting the cycle that will continue on forever.
This next theory is also based on the oscillating universe principle. Galaxies are moving further and further away from each other, but that rate is slowed by the force of gravity. Each galaxy will begin to collapse into a black hole in the future until the universe is made up of black holes. As these black holes continue to move apart the gravitational constant will be lowered. The black holes will begin to expand until they are nothing but a massive cloud of gas, gravel, and dust. This cloud will begin to condense until it forms a ultra dense body of matter. While it is condensing it will gain a massive amount of heat energy. This superheated ball of matter will then explode in a second big bang restarting the cycle.
This is the final oscillating universe theory. As the universe expands all of the galaxies move further and further apart. The gravitational force of the universe will pull them all back towards a central point. As all the galaxies come racing back towards one another they miss collision and continue to race past each other. After they miss each other they continue to expand outward again. They will continue to repeat this cycle. Since there is no collapse in the theory the stars will continue to lose their energy and the universe will become cold and dark. The universe will continue in this cycle and life as we know it will not be able to exist.
One of the most unlikely theories is that the universe will reach a maximum size and remain at that size. The currently expanding universe must have a certain density that is dependent on the expansion velocity. The force of gravity would slow down the expansion of the universe the exact same amount as the expansion reduces the pull of the gravity. Both of these would near zero but never quite reach it. As both forces approach zero the universe would attain its maximum size; neither contracting nor expanding. This theory is highly unlikely because it requires the perfect velocity and the perfect gravitational force.
A more interesting and less dismal theory is that the universe will continue to expand. As the universe continues to expand matter is formed from energy at a very small undetectable rate. This matter condenses and forms new galaxies in between existing galaxies. The universe will continue to grow indefinitely with galaxies at all stages of growth as new galaxies spring up in between old ones. The galaxies in the universe may have the outward velocities needed to overcome the gravitational force in the universe. As the galaxies expand stars will collapse and form black holes. These black holes will combine until the universe consists of black holes all moving apart. As these black holes continue to move apart the gravitational constant will be lowered. The black holes will begin to expand until they become a large, thin cloud of dust and gas. This cloud will continue to expand endlessly.
Another theory states that the universe will continue expanding. Most stars will die and fade until they come cold chucks of rock. Matter would collide with antimatter and become radiation energy or fall into black holes. Any remaining matter would begin to decay as gravity is diminished by the reduction of matter. Atoms would fall apart and form radiation. The only matter left would be left in black holes and this too will give off energy and lose all its matter. IN the end all that would be left is an expanding sea of radiation energy.
A final theory predicts the collapse of the universe. Currently the universe is expanding outward. It is thought that even though there isn?t enough visible matter to pull the universe back in, there may be enough mass in undetectable dark matter. If this is true the force of gravity will be strong enough to pull the universe back together. In the time that this takes to happen many starts will have collapsed and some will produce black holes. As the universe collapses more and more matter will be pulled into these black holes. Black holes will collide and combine. Eventually all the matter will be drawn into one universal black hole from which it can?t escape.
There are many different theories on the end of the universe. At this point we can only theorize as to what will happen because of limited amount of data. There are two important factors, which are needed to help marrow the number of theories. The first is the mass of the universe, which will help determine the force of gravity. The second is the velocity at which the universe is expanding. After knowing these two factors we will be closer to determining whether the universe will continue to expand or whether it will collapse. Only time will tell which of these proves to be true. Fortunately for us this time is billions of years and we all will not be around to find out what the outcome will be.