The topic I’m going to discuss is ‘How old is Everything?’ and by saying ‘Everything’ I mean the ‘Universe’.
No one is sure of the age of the Universe, for no one knows how it began. Some say it’s the ‘Big Bang’ and some say it is the ‘Steady State’. In fact there are many more theories put forward to explain the origin of the Universe. But there is no proof for any of the theories but Big Bang has more evidences. The only way to find out when the Universe originated is by moving back in time. We are slowly going to move back in time and see if the Universe existed at that point of time. So let’s get to it.
Universe certainly existed 4000 years ago as we do have some proof of human civilizations in Earth. The best example is Indus Valley Civilization and Egyptian Civilization. But no one knows what had been before that. Discovery of Jurassic bones helped us move a little further. These bones were tested and they were found to have lived about 2000 million years ago. And so we can certainly say that Earth did exist 2000 million years ago.
Some of the rocks on this planet were tested by scientists and they found some of the oldest rocks on the surface of the Earth. These rocks were found to be billions of years old. The oldest rock ever found was nearly 4.5 billion years old. That could be the time when Earth had formed or much before that. We could not find anything older than that and so we assume that Earth is actually 4.5 billion years old. Some scientists believe that the Earth was formed along with the other members of the solar system including the Sun. And so they think that our Solar System is also 4.5 billion years old.
We have some how estimated the age of the Earth but what about the Universe? How can we find out the age of the Universe? We can not take any samples from other stars to tests its age. It is merely impossible to reach other stars. Are there any other methods to find the age of the stars without reaching it?
The age of some of the stars can be found by testing the magnitude or intensity or the brightness of the star. By calculating the magnitude of the star, the amount of Hydrogen that has been burnt in the star can be estimated. With the help of this we can estimate the time when the star will die and also when it was born. Using this method the scientists have found that Sun has a life span of 10 billion years will die in another 5 billion years. This is very close to our assumption of the age of the Earth. So the solar system must be around the age to 4.5 to 5 billion years. The magnitude of the stars from some of the Globular Clusters were calculated. A Globular Cluster is a collection of stars which are bound by gravity. Most of the stars in a globular cluster are old. The above picture shows the Globular Cluster M13 found in the constellation of Hercules. The age of the stars in various clusters was estimated and it was found that the oldest globular cluster was around 11 to 18 billion years old. This is the lowest limit of the age of the Universe we could ever estimate from the stars. Scientists are still trying out various experiments to extend this limit. As of now the age of the Universe is 11 to 18 billion years old.
This information has been acquired from the net. If you have any further doubt or any questions about this topic you can with pleasure mail me via email. You can also visit this website for further details.
http://map.gsfc.nasa.gov/m_uni/uni_101age.html
