Astronomy’s 5 Big Questions
The article by David J. Eicher in the Astronomy magazine tries to answer 5 questions about the universe. The first problem is the Big Bang and how did it happen. It is rather difficult to be sure what was there before the Big Bang but it is possible to describe what happened after that. According to Eicher a powerful explosion of space-time sent matter and energy reeling outward into nothingness. At first it took a fracture of a second while the universe kept expanding but during hundreds of thousands of years, it has slowed down but it is still expanding. The second question that rises when studying the universe is “why don’t the galaxies fly apart when the stars circle around it?” Due to the fact that scientists were unable to explain this, they thought that a mysterious force must be holding the galaxies together. That mysterious force is called the Dark Matter. The third thing that fascinates scientists’ minds is how did the galaxies form? The first theory states that the galaxies collapse as single objects out of gas clouds. More and more gas falls in the galaxy because of the gravity and it starts spinning. The other theory is that galaxies of gas gravitate together and form a new galaxy. During a long time, a lot of galaxies are formed together like this. Despite the fact that we really don’t know what exactly happened, some kind of merging took place. The main question is that do gas-galaxies that merged together, had stars in them or they came into being within the galaxy. The third theory is that black holes brought the galaxies together because they are in the centre of almost all the galaxies. The stars evolving around the black hole were the lucky ones that weren’t sucked in by the black hole. The age of the universe has also been in question since the universe was discovered by mankind. Scientists are calculating its age by examining how fast the universe is expanding and how its speed is decreasing. For them...
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