Cosmic inflation

Our July talk was on “Inflation and the origin of cosmic structure”. Our speaker patiently presented a non-mathematical description of how in the early stages of the Universe (a fraction of a second only), it grew at an incredible rate before reaching the size of a pea and has since then has just been expanding (the term used for the more gradual increase after the inflation stage). Becoming the size of a pea might not sound that impressive but it does represent many orders of magnitude from its origin. The driving force seemed to be vacuum energy and negative pressure. This left most of us baffled, bewildered, sceptical or possible all three. How can a vacuum have energy ? And if it is nothing, then how can it exert a negative pressure? I couldn’t really get past the fact that I had eaten a helping of peas with my supper. The image of the Universe inside one of them was too much for me !

Other crazy ideas in science

It does all sound like a crazy idea but let’s rewind the clock and see some of the other crazy ideas Science has come up with. How would we have reacted to them? In 1633, Galileo was tried for heresy and threatened with the death sentence for his views on the heliocentric model of the Solar System. Seems so obvious now but what would we have thought then ? Where would we have stood on the famous Oxford debate about Darwin’s theory of evolution? That really shook the foundations of long-held established ideas . How about continental drift ? Continental drift ! Crazy, continents cannot drift. Poor Wegener never received any recognition for his ideas within his lifetime but once the mechanism of plate tectonics was established, it could be seen that he was right all along. Father and son, J. J. Thomson and George Thomson both received the Nobel Prize for apparently contradictory work – Thomson senior in 1906 for his work on the electron as a particle and Thomson junior in 1937 for his work on electron diffraction. Physics had been living with wave-particle duality ever since Einstein’s use of photons to explain the photoelectric effect so this pair of awards did not seem that strange. So perhaps in a few decades, vacuum energy and negative pressure will follow evolution, continental drift and wave-particle duality onto school and college syllabuses and nobody will think it odd at all. On the other hand… maybe a better explanation will come along and they will go the way of the ether, phlogiston, the flat earth theory and alchemy.

Talk on cosmic inflation given by David Wands of Institute of Cosmology and Gravitation, Portsmouth

Post written by Katherine Rusbridge

July 2013