We truly live in a very beautiful world, and that world is located in an even more charming universe. For anyone who has had the luck of gazing out towards the heavens on a dark night in a desert, you will surely agree that the view is more than majestic. While some think that all they see at night are just stars, there are actually some structures in the universe that are far grander than the stars. These are the galaxies, and they are also visible as points of light. But as stated, they are not just stars, but a bewildering collection of an uncountable number of stars, stellar dust and dark matter, all pulled together by the force of gravity.
These amazing structures have been studied for years, but up to this moment, scientists still cannot explain precisely how these galaxies were born. All that we know is that after the eventful Big Bang, what we now know as space was composed primarily of two gases – helium and hydrogen. Some scientists suggest that gravitational force held stellar dust and gas together and this led to the formation of stars and that this process continued until the galaxies were formed.
However, some other scientists have a different view as to how galaxies were established. They suggest that the body of galaxies were already formed before the stars were then sucked in. Till this very moment, scientists are still researching and trying to reach a provable consensus on precisely how the galaxies were created.
As at the beginning of the 20th century, scientists generally believed that all of the universe was confined into the Milky Way which is our own galaxy. But in 1924, an explosive discovery by Edwin Hubble showed convincingly that a lot more was existing beyond our own galaxy. Hubble made further discoveries that were so groundbreaking that our understanding of galaxies changed totally, and his works still greatly influence the field of astronomy until today.
Talking of how galaxies are determined, there are several properties that have been outlined by scientists. For example, a galaxy has a black hole at the centre, and these holes are incredibly powerful, so powerful that they emit waves that we can detect light years away. What this means is that galaxies are unbelievably active and vibrant. Another way to determine galaxies is to look at their shapes. There are those called spiral galaxies, and as the name states, they have arms that spiral from inside outwards. A vast majority of the galaxies that are visible to the astronomers are actually spiral galaxies, and it often looks like they are spinning. Galaxies are not individual in nature but form collections that are called clusters.