Expansion of Universe

The fact that the universe is expanding was established using the Doppler shift of light from different galaxies. Light emitted by star falls in continuous spectrum and as it passes through different stars the continuous spectrum is lost. Edwin Hubble, an American astronomer confirmed the existence of many galaxies other than Milkyway. He concluded that the galaxies are moving away from the earth and farther away the galaxy is from us, more is the speed. This can be established using a three dimensional coordinate system considering that the earth is at origin while the other coordinates represent various galaxies. Since universe is expanding, it is clear that the distance between galaxies and earth is also increasing. This increase is at a constant ratio k for a particular time t. Thus, it is clear that more the distance of the galaxy from earth more is its speed as compared to the galaxy nearby to it. This can be clearly explained by giving a simple example of inflating a football. If we mark different points on the football and inflate it with air, each point will find the other points moving away from it, and farther the point is, greater is the separation.


By: MOLLA RAMIZUR RAHMAN

Superstring Theory: The Excitement

        With the change in physics we are witnessing the better understanding of space, time and origin of the universe. The atoms were earlier considered to be the fundamental particles of the universe but with this theory in place, strings were placed as the fundamental particles of the universe. The birth of string theory has revolutionized the world of physics. Some people claim it to be the final theory - Theory of Everything (TOE). It is interesting to know that the whole of  information about the universe which has been collected over thousands of years can now be derived from this single theory as expected by the supporting physicists. German physicists have compiled the whole of physics in an encyclopedia. This new theory has been compared to the transition of man from real to complex numbers in mathematics. The theory with its elegant mathematics and beauty provides answer to many of the baffling questions which were not answered by the previous theories such as the existence of diversity of substances and billions of combinations. Only time will prove its accuracy, but for now we have a new theory with promising features.