COSMIC RAYS

Although the universe has been expanding since the initial Big Bang, inflation refers to the hypothesis that, for a very short time, the universe expanded at a sharply increasing rate, rather than at the decreasing rate it followed before inflation and has followed since. By some calculations, inflation increased the size of the universe by a factor of around 1026during that tiny fraction (far less than a trillionth) of a second, expanding it from smaller than the size of a proton to about the size of a grapefruit. Technically, the expansion during this period of inflation (and even the somewhat slower expansion which succeeded it) proceeded faster than the speed of light. To explain how this is possible (the speed of light being supposedly the maximum speed it is possible to travel), an analogy may help. If two airplanes are flying directly away from each other at their maximum speed of, say, 500 kilometres per hour, they are actually flying apart at 1,000 kilometres per hour even though neither individual plane is exceeding 500km per hour. Thus, “expansion”, in terms of the expanding universe, is not the same thing as “travel”. Cosmic inflation was first hypothesized by American physicist Alan Guth. He was trying to answer the question why distant parts of the universe were similar even though they couldn’t have shared a common history. In 1980, he proposed a radical solution. He theorized that 10-36 seconds after the Big Bang happened, all matter and radiation was uniformly packed into a volume the size of a proton. By the time it was 10-33 seconds old, its volume had increased by 1078 times — a period called the inflationary epoch. After this event, the universe was almost as big as an orange, expanding to this day but at a slower pace. While this theory was poised to resolve many cosmological issues, it was difficult to prove.  In March, 2014 Harvard-Smithsonian Centre for Astrophysics published the first pieces of evidence that cosmic inflation is right. This has significant implications for the field of cosmology. Astrophysics used the BICEP2 telescope from 2010 to 2012. It was equipped with a lens of aperture 26 cm, scanning an effective area of two to 10 times the width of the Moon. The results by Harvard-Smithsonian Centre for Astrophysics also highlight a deep connection between the theories of relativity and quantum mechanics. This has been the subject of a century-old quest in physics.

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