Great discoveries were made by great thinkers of their time like Galileo, Michellangello, and Capernicus which made signifigant contributions to modern thought. At their time it was believed that the earth was the centre of the universe and the sun rotated around it. They began to cast doubts on these beliefs with discoveries they made in their, by today's standards, simplistic telescopes but paid a heavy price as exile, isolation, ridicule, and even death. How could they even begin to imagine that our own galaxy is only a small frction or percentage of the universe. The Inca empire had the forsight to use the star movements to cordinate their agricultural practices. The Greeks, Chinese, and Arab civilzations used astronomical data for a variety of purposes including mathematics, future predictions. and the logging of time itself.
Today scientists can analyze we have billions of stars in the Milky Way galaxy which in turn has billions of other galaxies surrouding it. According to the Big Bang Theory our universe started at a point and has since expanded over billions of years and is still expanding, but in billions of years yet it will stop expanding. We appear to be in the centre of all this activity about this planet because looking out into the stars gives man a centralized perspective.
Hundreds of planets have been discovered, but we are the only known source to have life or evidence of its existance. They are still not sure if water has ever been available on Mars either present or past, or even some moons of Jupiter indicate traces of the possibilty of water. The conditions on our planet are perfect to create life as we know it and these conditions can not be found to be duplicated. To know that the human race is in a universe with billions of galaxies each with billions of stars should make mankind and womankind wonder their place in the world is.
Conditions in the universe are constantly fluctuating. Powerful telescopic images indicate some stars have exploded to form super novas. Our own sun has millions if not billions of years of existence still. Other images show the existance of black holes which are still a puzzle to explain even for leading astronomers. One very large black hole has been identified still quite a distance but is swallowing entire galaxies and everything in its path.
Our planet is also constantly changing in geography, plant and animal life, and even human life is evolving at an alarming rate. Plate techtonics causes portions of the earth to constantly shift, creating mountains where they meet and plains and valleys where they are seperating. At one time all the land on this planet was joined to form one large land mass and over millions of years they have seperated to create seven continents: North and South America, Asia, Europe, Africa, Australia, and Antartica. But these continents will inevitably over millions of years again join to form one huge super continent. They move centimeters a year but will merge to form even higher mountains than the Himalayan Mountains. Charles Darwin proved to us that life is constantly changing to better adopt to its environment. On the bottom of the oceans where geysers spew with fissures from the earth's mantle are seeping into the bottom. New forms of life appear to be developing unknown to mankind with adifferent physical makeup from what we know, are thriving in these areas. Polar icecaps are predicted to change by their calculations and the north and south poles will reverse over time. This happens every few million years. This has already happened and predictions necessitate it can happen again.
With these constant changes on our planet and the universe, mankind can only feel that they have barely touched the tip of the iceberg towards exsplaining if other life exists.... or are we alone in the universe?